60. Tagung der Arbeitsgemeinschaft der Institute für Bienenforschung e.V.

19., 20. und 21. März 2013

Universität Würzburg

Lehrstuhl für Tierökologie und Tropenbiologie

2

Inhalt Willkommen ........................................................................................ 3

Programm ........................................................................................... 4

Hauptvorträge ................................................................................... 10

Symposia ........................................................................................... 11

1. Honig- & Wildbienenökologie ................................... 11

2. Pflanzenschutz & Bestäubung ................................... 14

3. Physiologie & Verhalten ........................................... 18

4. Bienenpathologie ..................................................... 23

5. Bienenprodukte & Sonstiges .................................... 29

6. Genetik & Zucht ........................................................ 33

Posterpräsentationen ........................................................................ 37

1. Honig- & Wildbienenökologie ................................... 37

2. Pflanzenschutz & Bestäubung ................................... 43

3. Physiologie & Verhalten ........................................... 46

4. Bienenpathologie ..................................................... 56

5. Bienenprodukte & Sonstiges .................................... 65

6. Genetik & Zucht ........................................................ 71

Lageplan: Campus Am Hubland ......................................................... 76

3

Willkommen

Liebe Kolleginnen und Kollegen,

es ist uns ein besonderes Vergnügen die diesjährige 60. Jahrestagung der Arbeitsgemeinschaft der Institute für Bienenforschung hier an der Universität Würzburg zu organisieren. Bienenforschung hat in Würzburg eine lange Tradition und ist nach wie vor ein wichtiger Bestandteil in Lehre und Forschung. In dem neuen SFB “Insect timing: mechanisms, plasticity and interactions” beschreiten wir am Biozentrum neue Wege in der Kooperation zwischen Ökologen, Neurobiologen und Verhaltensphysiologen mit der Honigbiene als wichtigem Modellorganismus.

In diesem Jahr wird ein Schwerpunkt der Tagung, entsprechend unserer Ausrichtung, auf der Ökologie von Honig- und Wildbienen liegen. Für die Hauptvorträge konnten wir Prof. Dr. Alexandra-Maria Klein, Leuphana Universität Lüneburg, sowie Prof. Dr. Koos Biesmeijer, Naturalis Biodiversity Center Leiden, gewinnen. Ihre Vorträge werden sich mit den Ursachen für den Rückgang von Honig– und Wildbienen sowie den Konsequenzen für die Bestäubung von Kulturpflanzen durch Bienen befassen.

Als Veranstalter der 60. Jahrestagung möchten wir Sie herzlich in Würzburg begrüßen. Wir hoffen auf einen angenehmen Aufenthalt und eine wissenschaftlich und persönlich bereichernde Tagung. Bitte genießen Sie neben den spannenden Vorträgen und Postern die fränkische Kultur, sei es das UNESO Weltkulturerbe Residenz Würzburg oder ein guter Tropfen Wein. Wir freuen uns auf eine interessante und informative Tagung, lebhafte Diskussionen und den persönlichen Austausch mit Ihnen. Würzburg, im März 2013

Ingolf Steffan-Dewenter Stephan Härtel

4

Programm Dienstag, 19.03.2013

13.00h Begrüßung

14.00h Hauptvortrag: Bienenvielfalt für die Bestäubung von Kulturpflanzen Alexandra-Maria Klein (Leuphana Universität Lüneburg)

Session 1: Honig- & Wildbienenökologie (Chair: Rob Paxton)

15.00h SB Impact of mass flowering oilseed rape on pollen foraging of honey bees - Einfluss der Massentracht Raps auf das Pollensammelverhalten von Honigbienen Nadja Danner, S. Härtel, I. Steffan-Dewenter (Würzburg, ZOO III)

15.15h SB The influence of oilseed rape on pollinators and the pollination of wildplants on seminatural grassland - Der Einfluss von Raps auf Bestäuber und die Bestäubung von Wildpflanzen auf Magerrasen Daniela Carstens, V. Riedinger, I. Steffan-Dewenter, A. Holzschuh (Würzburg, ZOO III)

15.30h SB Sown flower strips as measure to enhance pollinators in agricultural landscapes. Blühstreifen als Maßnahme zur Förderung von Bestäubern in Agrarlandschaften Béatrice Portail, V. Riedinger, I. Steffan-Dewenter, A. Holzschuh (Würzburg, ZOO III)

15.45h Wild bees must be considered in the case of project and management plans in habitats – a case study - Wildbienen müssen Berücksichtigung auch bei Eingriffen und Pflegemaßnahmen in Lebensräume finden – ein Fallbeispiel Otto Boecking, M. Schreiber (Celle)

16.00h Kaffeepause

Session 2: Pflanzenschutz & Bestäubung (Chair: Klaus Wallner)

16.30h SB BICOPOLL - Targeted precision biocontrol and pollination enhancement in organic cropping systems - Flying doctors zur Grauschimmelbekämpfung und als Bestäuber im ökologischen Erdbeeranbau – erste Untersuchungsergebnisse im BICOPOLL Projekt Victoria Kreipe, O. Boecking (Celle)

16.45h An interim report of a field study of bee colonies chronically fed with 200 or 2000ppb of thiacloprid - Zwischenergebnisse eines Langzeitfeldversuchs mit Bienenvölkern, die mit 200 oder 2000ppb Thiacloprid haltigem Zuckersirup gefüttert wurden Reinhold Siede, L. Faust, C. Maus, M. Meixner, B. Grünewald, R. Büchler (Kirchhain, Oberursel)

5

17.00h SB Neonicotinoids interfere with navigation in honeybees - Neonicotinoide beeinflussen die Navigation von Honigbienen Johannes Fischer, T. Müller, A.-K. Spatz, U. Greggers, B. Grünewald, R. Menzel (FU Berlin; Oberursel)

17.15h SB Effects of the neurotoxic insecticide thiacloprid on the flight behavior of honeybees - Effekte des neurotoxischen Insektizides Thiacloprid auf das Flugverhalten von Honigbienen Lena Faust, J. Hahn, B. Grünewald (Oberursel)

17.30h Interactions between microsporidia, viruses and pesticides in larvae and adult honey bees - Interaktionen zwischen Mikrosporidien, Viren und Pestizide bei ihrem Einfluss auf Larven und erwachsenen Honigbienen Vincent Doublet, M. Labarussias, M.E. Natsopoulou, J. Steinberg, A. Miertsch, J.R. de Miranda, R.J. Paxton (Halle, Allg. Zool.; Uppsala)

17.45h SB Synergistic effects of Nosema ceranae and sublethal doses of Thiacloprid, τ-Fluvalinate and Clothianidin on bees (Apis mellifera L.) in mating hives Synergistische Effekte von Nosema ceranae und subletalen Dosen von Thiacloprid, τ-Fluvalinat und Clothianidin auf Bienenvölker (Apis mellifera L.) im Kieler Begattungskästchen Richard Odemer, T. Stahl, P. Rosenkranz (Hohenheim)

18.00h Wein- und Sektempfang mit freundlicher Unterstützung der LWG Veitshöchheim und dem Fränkischen Weinbauverband e.V.

19.00h Mitgliederversammlung (nicht öffentlich, Raum 2.013)

Mittwoch, 20.03.2013

08.30h Bericht der Mitgliederversammlung

09.00h Hauptvortrag: Pollinator declines in Europe: patterns and drivers Koos Biesmeijer (Leiden, The Netherlands)

Session 3: Physiologie & Verhalten (Chair: Michael Lattorff)

10.00h SB Trans-generational immune priming in honeybees – Generationsübergreifende Immunisierung bei Honigbienen Javier Hernández-López, W. Schuehly, U. Riessberger-Gallé, K. Crailsheim (Graz)

10.15h SB Dose-dependent effects of transgenic pollen on honey bee larvae - Dosisabhängige Auswirkungen transgener Pollen auf Honigbienenlarven Karin Steijven, I. Steffan-Dewenter, S. Härtel (Würzburg, ZOO III)

10.30h Kaffeepause

6

11.00h SB Experiments on the choice of water foraging honeybees (Apis mellifera L.) under semi-field conditions - Versuche zum Wahlverhalten von Wasser sammelnden Bienen (Apis mellifera L.) im Halbfreiland Jana Reetz, K. Wallner (Hohenheim)

11.15h Proteins of royal jelly: evolution and function in social insects - Proteine des Weiselfuttersaftes: Evolution und Funktion bei den sozialen Insekten Stefan Albert, J. Spaethe, K. Grübel, W. Rössler (Würzburg, ZOO II)

11.30hSB Fertility of honeybee workers is mediated by Epidermal Growth Factor Receptor (EGFR) - Die Fruchtbarkeit von Honigbienenarbeiterinnen wird durch EGFR (Epidermaler Wachstumsfaktor Rezeptor) vermittelt E.M. Formesyn, D. Cardoen, Ulli Ernst, E. Danneels, M. Van Vaerenbergh, D. De Koker, P. Verleyen, T. Wenseleers, L. Schoofs, D.C. de Graaf (Ghent, Leuven)

11.45h Conditioning of honeybee colony on TNT and DNT scent - Konditionierung von Honigbienen Völkern auf TNT und DNT Duft Nikola Kezić, M. Janeš, J. Filipi, M. Dražić, K. Crailsheim, Y. Leconte, N. Pavković (Zagreb, Knin, Graz, Avignon)

12.00h SB The upper lethal temperature of Apis mellifera carnica and A. m. ligustica Die obere Lethaltemperatur von Apis mellifera carnica und A. m. ligustica Helmut Kovac, A. Stabentheiner, C. Costa (Graz, Bologna)

12.15h Advances in the cryopreservation of honey bee drone semen Fortschritte bei der Kryokonservierung von Drohnensperma Jakob Wegener, T. May, G. Kamp, K. Bienefeld (Hohen Neuendorf, Mainz)

12:30h Mittagspause

14.-16:00h Poster Session mit Kaffee

16.15h Bus Abfahrt zur Residenzführung

16:45h Residenzführung

18:15h Weinprobe: Bürgerspital Weinstuben

19.00h Gesellschaftsabend: Bürgerspital Weinstuben

Donnerstag, 21.03.2013

Session 4: Bienenpathologie (Chair: Marc Schäfer)

09.00h Coordinated treatment of Varroa destructor to reduce reinvasion - Koordinierte Bekämpfung von Varroa destructor zur Reduktion der Reinvasion Jochen Pflugfelder (Liebefeld)

7

09:15h Function and efficacy of the Varroa-Gate, a device in the hive entrance for the control of Varroa destructor infestations in honey bees. - Funktion und Wirkungsweise des Varroa-Gates, einer Fluglochapplikation zur Kontrolle von Varroa destructor Infestationen bei Honigbienen G. Koeniger, Nikolaus Koeniger, B. Grünewald, K. Krieger (Oberursel, BAYER/Monheim)

09:30h Do not fight against Varroa - get rid of it! - Warum Varroa bekämpfen, wenn Bienenhaltung ohne Varroa möglich ist? Heikki M.T. Hokkanen, I Menzler-Hokkanen (Helsinki)

09.45h SB DWV/VDV-1 and overwinter colony losses in Germany - DWV/VDV-1 und Winterverluste bei Honigbienenkolonien in Deutschland Myrsini E. Natsopoulou, D.P. McMahon, V. Doublet, V. Maibach, E. Frey, P. Rosenkranz, R.J. Paxton (Halle, Allg. Zool.; Hohenheim)

10.00h SB Comparison of colony health in wild and managed honeybees Vergleich des Virenbefalls zwischen wilden Honigbienen und Imkerbienen Matthias Y. Mueller, B.F. Kraus, R.F.A. Moritz (Halle, Mol. Ökol.)

10.15h Comparison of the efficacy of Formic Acid 60% and 85% as Varroa treatment applied in two different evaporation systems. - Vergleich der Wirksamkeit von Ameisensäure 60% und 85% zur Varroabekämpfung in zwei verschiedenen Verdunstungssystemen. Peter Rosenkranz, P. Aumeier, S. Berg, O. Boecking, R. Büchler, W. Kirchner, T. Kustermann, C. Otten, A. Reichart, W. von der Ohe (Bochum, Celle, Hohenheim, Kirchhain, Mayen, Veitshöchheim)

10.30h Kaffeepause

11.00h SB Infestation of midgut epithelium in Nosema tolerant and susceptible honey bee strains towards N. ceranae infections - Infestation des Mitteldarm Epitheliums in Nosema toleranten und anfälligen Honigbienen Stämmen bei N. ceranae Infektionen Q. Huang, Christoph Kurze, R.F.A. Moritz (Halle, Mol. Ökol.)

11.15h Winter mortality, varroa control, viruses, Nosema spp., a retrospective study 2010-2012 in the Netherlands – Winter-Mortalität, Varroa Kontrolle, Viren und Nosema – eine retrospektive Studie 2010-2012 in den Niederlanden Sjef van der Steen, B. Cornelissen, C Hokahin (Wageningen)

11.30h SB Different strategies of Paenibacillus larvae to evade the immune response of honey bee larvae - Verschiedene Strategien von Paenibacillus larvae die immune Reaktion der Honigbienenlarve zu umgehen Gillian Hertlein, L. Poppinga, E. Garcia-Gonzalez, A. Fünfhaus, K. Hedtke, E. Genersch (Hohen Neuendorf)

8

11.45h SB Annotation of genes encoding G-protein-coupled receptors for biogenic amines in the parasitic mite Varroa destructor - Annotation von Genen für G-Protein-gekoppelte Rezeptoren für biogene Amine in der parasitischen Milbe Varroa destructor Sebastian Wernig, W. Blenau (Oberursel)

12.00h Mittagspause

Session 5: Bienenprodukte & Sonstiges (Chair: Ingrid Illies)

13.15 Comparison of new computer methods for honeybee colony assessment – Ein Vergleich neuer Bildverarbeitungsmethoden zur Abschätzung der Koloniegröße von Honigbienen Markus Wang, L. Brewer (Heidelberg)

13.30h The same procedure as every year? Comparison between the years 2011 and 2012 of FitBee Module 5 - Gleiche Ergebnisse bei gleicher Vorgehensweise? Vergleich 2011 & 2012 des FitBee Moduls 5 W. von der Ohe, Dorothee J. Lüken (Celle)

13.45h Is drone brood removal an efficient treatment against Varroa? - Ist die Entnahme von Drohnenbrut eine Effiziente Methode gegen Varroa? Manuel Tritschler (Monheim)

14.00h The pollinator discussion in Brazil - consequences for us Die Bestäuber-Diskussion in Brasilien – Konsequenzen für uns Wolf Engels (Tübingen, São Paulo)

14.15h SB Effective harvesting methods for propolis in Germany: A field-trial Effektive Propolisernte in Deutschland: Ein Praxistest Nadine Kunz, A. Schroeder (Hohenheim)

14.30h Project „Healthy Colonies“ – How may an improved consultation of beekeepers look like? - Projekt „Gesunde Bienenvölker“ – Wie kann eine verbesserte Beratung von Imkern aussehen? Gefion Brunnemann-Stubbe, V. Poker, R. Büchler (Kirchhain)

Session 6: Genetik & Zucht (Chair: Helge Schlüns)

14.45h SB Spatial and temporal expression patterns of serotonin receptor subtypes in the honeybee, Apis mellifera - Räumliche und zeitliche Expressionsmuster von Serotonin-Rezeptor-Subtypen der Honigbiene, Apis mellifera Daniel Rolke, M. Thamm, W. Blenau (Oberursel, Potsdam)

15.00h SB Colony performance, behavior and disease susceptibility of two genotypes from Apis mellifera macedonica population in the Republic of Macedonia - Leistung, Verhalten und Krankheitsanfälligkeit zwei verschiedener Apis mellifera macedonica Genotypen in der Republik Mazedonien Aleksandar Uzunov, R. Büchler (Skopje, Kirchhain)

9

15.15h Adaptive Evolution of RNAi Genes in Bumblebees - Adaptive Evolution von RNAi Genen bei Hummeln H. Michael G. Lattorff, S. Helbing (Halle, Physiol., Halle, Mol. Ökol.)

15.30h Using DNA pools for genotyping colonies of the honeybee Apis mellifera with microsatellite DNA. - Nutzung von DNA-pools zur Genotypisierung von Honig- bienenkolonien, Apis mellifera, mit Microsatellite DNA. Nadège Forfert, E.A. Schlüns, O.R. Paniti-Teleky, E.M. Furdui, D.S. Dezmirean, R.F.A. Moritz (Cluj-Napoca, Osnabrück, Halle, Mol. Ökol.)

15.45h Evenius-Preisverleihung und Verabschiedung

10

Hauptvorträge Wir freuen uns Ihnen zwei interessante Hauptvorträge ankündigen zu können: Bienenvielfalt für die Bestäubung von Kulturpflanzen

Prof. Dr. Alexandra Klein, Institut für Ökologie, Leuphana Universität Lüneburg

Der Rückgang der Imkerei und die Zunahme an Völkerverlusten in vielen Regionen der Welt führen zu allgemeinen Befürchtungen über Bestäubungsdefizite für landwirtschaftliche Kulturen. In meinem Vortrag werde ich zeigen, wie sich die Produktion von bestäubungsabhängigen Kulturen regional und global entwickelt und die Bedeutung der Bestäubung im Hinblick zu anderen produktionssteigernden Maßnahmen betrachten. Weiter werde ich zeigen, welche Insektengruppen zur Bestäubung beitragen und wie die Bestäubungsmechanismen aussehen. Dabei werde ich auch auf die Gefährdungsursachen von Bienen und anderen bestäubenden Insekten eingehen. Anhand verschiedener Beispiele zur Kulturpflanzenbestäubung werde ich verdeutlichen, warum nicht nur die Europäische Honigbiene, sondern auch Wildbienen und andere Insekten, benötigt werden, um die Bestäubungsleistung in landwirtschaftlichen Kulturen zu sichern. Der Hauptfokus wird dabei auf neuen Ergebnissen zur Mandelbestäubung in Kalifornien liegen, aber auch andere Kulturpflanzen und deren Bestäuber-Lebensgemeinschaften aus den Tropen und gemäßigten Breiten werden angesprochen und globale Muster zu Bestäubungsdefiziten und deren Ursachen aufgezeigt. Der Vortrag richtet sich an ein breites Publikum verschiedener Interessensgruppen (u.a. Studenten, Wissenschaftler und Imker), mit dem Ziel, die Bedeutung der Honigbiene und Wildbienen für die Kulturpflanzenbestäubung besser zu verstehen.

Pollinator declines in Europe: patterns and drivers

Dr. Koos Biesmeijer, Naturalis Biodiversity Center Leiden There is some evidence for declines or at least shifts in wild pollinators and managed honeybees in Europe. However, reports are often very local and always very clear. We have gathered data from the last 60yrs and three countries to see how wild bees have changed in W-Europe. Analyzing the causes of these changes is even more difficult, but with an active European research community and good collaboration we manage step-by-step to get better understanding of how and why pollinators are changing in Europe. This knowledge is needed to be able to design management measures that can help to maintain bees in our landscapes that can continue to provide their important pollination services in the future.

11

Symposia

1. Honig- & Wildbienenökologie 1.1 Impact of mass flowering oilseed rape on pollen foraging of honey bees - Einfluss der Massentracht Raps auf das Pollen-Sammelverhalten von Honigbienen Nadja Dannerˢ, S. Härtel, I. Steffan-Dewenter (Würzburg, ZOO III)

Pollen traps or honey are often used for determining the spectrum of bee visited plant species. However, important aspects of honey bee ecology such as foraging distances of colonies and exact locations of visited flower sources cannot be addressed by these methods. Data on foraging distances are essential to assess the potential exposure of honey bee colonies to threats related to intensively managed mass flowering crop fields. Decoding the waggle dance provides a unique possibility to systematically analyze honey bee resource use at a landscape scale because the vast majority of forager trips are guided through this unique behavior. While mass flowering oilseed rape is known to be an attractive nectar and pollen source, there is no information about possible differences in pollen foraging distances and the relative attractiveness of oilseed rape compared to wild flower sources available. We chose 16 landscapes in the surrounding of Würzburg, Germany, with independent gradients according to area of oilseed rape and semi-natural habitat in a 2 km radius. In the centre of each landscape observation hives were placed and regularly rotated among sites during and after bloom of oilseed rape. Waggle dances of pollen foragers were observed for 90 minutes per colony within one observation cycle during several consecutive days, followed by rotation of all hives and the next observation cycle (8 in total). By using this experimental approach on a landscape scale, we answer the following questions: how does oilseed rape cover influence pollen foraging distances and used pollen diversity of honey bee colonies? How important are semi-natural habitats concerning pollen foraging and is there a difference between seasons? Our results will give first insights of how a mass flowering crop influences honey bee pollen foraging ecology. We further discuss the potential exposure of honey bee colonies to crop pollen contaminated by pesticides in intensively used agricultural landscapes.

1.2 The influence of oilseed rape on pollinators and the pollination of wildplants on seminatural grassland - Der Einfluss von Raps auf Bestäuber und die Bestäubung von Wildpflanzen auf Magerrasen

Daniela Carstensˢ, V. Riedinger, I. Steffan-Dewenter, A. Holzschuh (Würzburg, ZOO III) Bienen spielen eine wichtige Rolle für die Bestäubung von Wild- und Kulturpflanzen. Dabei kann es zur Konkurrenz zwischen den Massentrachten in der Agrarlandschaft und Wildpflanzen in naturnahen Habitaten um Bestäuber kommen. Im Rahmen des EU-Projektes STEP wurde der Einfluss der Rapsanbaufläche auf die

12

Blütenbesuchergemeinschaften und den Samenansatz der beiden Wildpflanzen Hippocrepis comosa und Thymus praecox auf 16 Magerrasen im Raum Würzburg untersucht. Mit Bestäuberausschluss-Experimenten wurde zunächst die Abhängigkeit der Pflanzen von Insektenbestäubung überprüft. Des Weiteren wurden bei Transektgängen (150 m²) die Abundanz von solitären Wildbienen, Hummeln und Honigbienen auf den Fokuspflanzen erfasst. Für H. comosa wurden die Aufnahmen während und nach der Rapsblüte durchgeführt, für T. praecox erst nach der Rapsblüte. Zusätzlich wurde der Anteil an Raps in 1 km Radius um die Versuchsflächen bestimmt. Es konnte bestätigt werden, dass H. comosa allein von Insektenbestäubung abhängt, da unter Bestäuberausschluss keine Früchte gebildet wurden. Bei T. praecox führte der Bestäuberausschluss zu niedrigeren Samenzahlen pro Blütenkelch im Vergleich zu offen bestäubten Pflanzen. Mit zunehmendem Rapsanteil in der Landschaft nahm die Abundanz der Wildbienen auf H. comosa unabhängig vom Zeitpunkt ab. Bei den Hummeln spielte der Zeitpunkt der Beobachtung eine Rolle. Während der Rapsblüte nahm die Abundanz der Hummeln mit dem Rapsanteil ab, nach der Rapsblüte führte ein höherer Rapsanteil zu einer höheren Abundanz auf H. comosa. Die Abundanz der Bienen auf T. praecox wurde nicht durch den Rapsanteil in der Landschaft beeinflusst. Folglich kann ein erhöhter Rapsanteil dazu führen, dass Bestäuber den Magerrasen fern bleiben und vermehrt die Massentracht nutzen. Die Auswirkungen dieser möglichen Konkurrenz um Bestäuber auf den Samenansatz und damit die Fitness von Wildpflanzen muss noch näher untersucht werden. 1.3 Sown flower strips as measure to enhance pollinators in agricultural landscapes - Blühstreifen als Maßnahme zur Förderung von Bestäubern in Agrarlandschaften

Béatrice Portailˢ, V. Riedinger, I. Steffan-Dewenter, A. Holzschuh (Würzburg, ZOO III )

Die Intensivierung der Landwirtschaft führt zum Verlust von Bestäubern in Agrarlandschaften. Agrarumweltmaßnahmen, beispielsweise die Anlage von Blühstreifen, soll dem entgegen wirken. Die Bedeutung von ausgesäten Blühstreifen im Vergleich zu Ackerrandstreifen für Bienen ist dabei nur unzureichend bekannt. Auch die umgebende Landschaft kann die Effektivität von Blühstreifen beeinflussen. Um diese Fragestellungen zu untersuchen wurden 2011 im Rahmen des EU-Projektes STEP (Status and Trends of European Pollinators) acht 300 m² große Blühstreifen im Raum Würzburg ausgesät. In jeder der acht Untersuchungsgebiete wurde 2012 die Abundanz und Artenvielfalt von Honigbienen, Hummeln und solitären Wildbienen auf dem angelegten Blühstreifen und als Kontrolle auf Ackerrandstreifen bei Transektbegehungen erfasst. Als zusätzliche Kontrolle wurde in acht weiteren Landschaften ohne angelegte Blühstreifen jeweils ein Ackerrandstreifen untersucht. Außerdem wurde der Anteil von naturnahen Habitaten und Rapsfeldern in 1 km Radius um die Untersuchungsflächen berechnet. Es wurden signifikant mehr solitäre Wildbienen auf den Blühstreifen im Vergleich zu den Ackerrandstreifen erfasst. Unabhängig vom untersuchten Habitat wurden nach dem Verblühen des Rapses mehr Hummeln in Landschaften gezählt, die eine hohe Rapsanbaufläche aufwiesen. Mit zunehmendem Anteil an naturnahen Habitaten nahm

13

die Gesamtzahl der Bestäuber auf den verschiedenen Habitaten ab. Dies zeigt, dass angelegte Blühstreifen sowie ungenutzte Ackerrandstreifen attraktiver werden, wenn der Anteil an naturnahen Lebensräumen abnimmt. Bei der Etablierung von Blühstreifen sollte deshalb die umgebende Landschaft berücksichtigt werden. 1.4 Wild bees must be considered in the case of project and management plans in habitats – a case study - Wildbienen müssen Berücksichtigung auch bei Eingriffen und Pflegemaßnahmen in Lebensräume finden – ein Fallbeispiel Otto Boecking, M. Schreiber (Celle)

Wildbienen sind aufgrund ihrer oft sehr engen Bindung an bestimmte Pflanzen und spezifischen Nistplatzwahl besonders für die Bewertung von Lebensräumen geeignet. Oligolektische Arten, wie Colletes succinctus und Andrena fuscipes, die ihren Pollen zur Versorgung ihrer Larven ausschließlich an Heidekrautgewächsen und hier insbesondere an Caluna vulgaris sammeln, übernehmen für Heiden als charakteristische Arten und als Bestäuber eine besondere Schlüsselfunktion. Am Beispiel einer geplanten Pflegemaßnahme an einer isoliert gelegenen Heidefläche, die den negativen Einfluss von atmogenen Nährstoffeinträgen reduzieren soll, wird gezeigt, dass die Belange der Wildbienen berücksichtigt werden müssen. Eine Erfassung der Wildbienen während der Heideblüte entlang eines zuvor festgelegten Linientransektes zeigte, dass beide für Heiden charakteristischen Wildbienenarten angetroffen wurden. Ebenso deren Kuckucksbienen Epeolus cruciger und Nomada rufipes. Insgesamt waren jedoch nur sehr geringe Individuenzahlen nachweisbar und das Wirt-Parasit Verhältnis zu Gunsten der Parasiten verschoben. Pflegemaßnahmen, die für Heideflächen in der Beweidung, Mahd, oberflächlichem Abbrennen oder Schoppern und Abplaggen bestehen können, stellen für die charakteristischen Tierarten der Heiden gleichzeitig einen massiven Eingriff und fundamentale Veränderungen bzw. Zerstörung ihres Lebensraumes über Jahre hinweg dar. Die Ansprüche der lokalen Wildbienenpopulationen müssten bei der Planung jeglicher zukünftiger Pflegemaßnahme der Heidefläche mitberücksichtigt werden, wie es an diesem Fallbeispiel belegen ist. Ansonsten würden der Rest der lokalen Wildbienenpopulationen womöglich ausgelöscht werden.

14

2. Pflanzenschutz & Bestäubung 2.1 BICOPOLL - Targeted precision biocontrol and pollination enhancement in organic cropping systems - Flying doctors zur Grauschimmelbekämpfung und als Bestäuber im ökologischen Erdbeeranbau – erste Untersuchungsergebnisse im BICOPOLL Projekt

Victoria Kreipeˢ, O. Boecking (Celle)

Organic berry and fruit production suffers heavily from the lack of effective disease and pest management tools, and from inadequate insect pollination at times. As a consequence, the expanding demand on organic berries cannot be filled today. BICOPOLL expects to change this, and to significantly improve the yield and quality of organic fruit and berry production and thus, farm economics. We will use bees to (i) target deliver biological control agents to the flowers of the target crops to provide control of problem diseases, and to (ii) improve the pollination of organic horticultural crops. We will provide a pan-European case study on protecting organic strawberry from its most important disease, the grey mould. We will improve the efficiency of the entomovector technology via innovative research on bee management, manipulation of bee behavior, components of the cropping system, and on the plant-pathogen-vector-antagonist–system, and will investigate possibilities of expanding the use of the concept into other organic berry and fruit growing systems. This is a highly innovative approach to solving some of the most difficult disease and pest problems in organic berry and fruit production, offering solutions in areas where no solutions as yet exist.

2.2 An interim report of a field study of bee colonies chronically fed with 200 or 2000ppb of thiacloprid - Zwischenergebnisse eines Langzeitfeldversuchs mit Bienenvölkern, die mit 200 oder 2000ppb Thiacloprid haltigem Zuckersirup gefüttert wurden.

Reinhold Siede, L. Faust, C. Maus, M. Meixner, B. Grünewald, R. Büchler (Kirchhain, Oberursel)

Some neonicotinoides are highly toxic to honeybees. However, cyano-substituted compounds as thiacloprid are intrinsically less toxic. Laboratory assays have shown that bees can effectively detoxify thiacloprid. However, there are concerns about potential long-term effects on the colonies under field conditions. To identify potential hazards colonies were chronically fed with sublethal concentrations of thiacloprid and observed for 10 months. We report results from the first 2 years from a planned period of 3 years. In July 2011 and July 2012, respectively, 30 colonies were started from shook swarms, divided into three groups with ten colonies each, and migrated to an experimental yard. Five times per autumn they were provided with sugar syrup containing either 200 ppb or 2000 ppb thiacloprid or syrup alone (control). Every 3 weeks the colonies were weighed,

15

their brood area measured and their strengths estimated. Dead bees were counted in entrance traps. Honey and bee bread were sampled two times per year for analyzing residues of thiacloprid using LC-MS/MS. At the end of the feeding periods differences between groups in number of bees and brood per colony were low (means from 2011: control: 13,200 bees; 3,462 brood cells; 200ppb: 11,980; 3,503; 2000ppb: 11,133; 2,543; means from 2012: control: 8,590; 2,403; 200ppb: 9,175; 1,792; 2000ppb: 8,075; 2,243). The data will be statistically analyzed with linear mixed models. Residues of thiacloprid in honey did not significantly correlate with the number of bees, of brood and dead bees (spearman rang correlation, p≥0.09, 90 observations). No winter loss occurred. So far our study does not indicate that colony vitality parameters are affected by a long-term feeding with 200 or 2000ppb thiacloprid. This study is part of the FITBEE-project supported by funds of the German Federal Ministry of Food, Agriculture and Consumer Protection (BMELV) via the Federal Office for Agriculture and Food (BLE) under the innovation support program.

2.3 Neonicotinoids interfere with navigation in honeybees - Neonicotinoide beeinflussen die Navigation von Honigbienen

Johannes FischerS, T. Müller, A.-K. Spatz, U. Greggers, B. Grünewald, R. Menzel (Oberursel, Berlin)

Honeybees may encounter a variety of harmful chemicals during foraging. Among them are the neonicotinoid insecticides that are widely used in agriculture. They act as agonists of the insect acetylcholine receptor and are supposed to have only minor effects on the mammalian central nervous system, and are, thus, regarded harmless to humans and farm animals. Bees that were exposed to non-lethal doses of different neonicotinoids show various influences on behavior or motor activity, depending on the encountered substance. We investigated the influences of the neonicotinoids clothianidin, imidacloprid and thiacloprid on the ability of honeybee foragers to orientate during homing flights. Individual bees were equipped with a transponder and their flight trajectories tracked with harmonic radar. The bees were trained to an artificial feeder, then caught and fed with sugar water containing one of the neonicotinoids. Subsequently they were displaced and released about 300m from the hive. We recorded the flight traces from the release site back to the hive and expectedly observed that bees rely initially on vector-orientation confirming earlier findings. All bees headed first into a direction in which they expected to find their hive, if they would have returned from the feeder. The influence of the different treatments became apparent during the following part, which we called the homing flight, i. E., the way from the expected hive site to the real hive. Thiacloprid (0.1mM, 50µl) and imidacloprid (0.6µM, 50µl) treatments led to a temporary inability to find the hive, resulting in a significant reduced number of bees that returned to the hive in the observation period(thiacloprid 27.4%, imidacloprid 42.7%, control 88%). Bees rely on both landmark- and vector-orientation during normal orientation, e. g., while performing a foraging flight. Our data suggest that neonicotinoids may influence especially landmark-orientation orientation in bees.

16

2.4 Effects of the neurotoxic insecticide thiacloprid on the flight behavior of honeybees - Effekte des neurotoxischen Insektizides Thiacloprid auf das Flugverhalten von Honigbienen

Lena FaustS, J. Hahn, B. Grünewald (Oberursel) While foraging, honeybees may get in contact with the insecticide thiacloprid that is known for its relative low toxicity to bees, though sublethal effects are not studied very well yet. By using the RFID technique, we examine the influences of sublethal doses of thiacloprid on the flight behavior of honeybees. To study the effects of chronic feeding of larvae with thiacloprid, we simulated the consumption of thiacloprid via nectar by feeding colonies with sugar syrup containing 5000 ppb thiacloprid in the hive, respectively with pure sugar syrup for control. After eclosion of the first generation of experimental bees they were labeled with RFID microchips to record them leaving or returning to the hive. To estimate the date of death for each marked bee, the day of the last registration was noted. Bees of colonies fed with sugar syrup containing 5000 ppb thiacloprid started significantly later for their first flight and lived significantly longer than bees fed with pure sugar syrup. No referable differences in the time spent outside of the hive and the number of flights were observed. We investigated secondly whether and how an acute uptake of 250 ng thiacloprid per bee influences the homing flight behavior of honeybees. Adult bees were caught upon leaving the hive, chipped with RFID microchips and brought to release sites at distances between 200 and 900 meters from the hive. They were fed with 10 µl of diluted honey either with thiacloprid added or without and then were allowed to imbibe pure diluted honey ad libitum. Immediately they were released and the duration they required to get back to the hive was evaluated. The duration of homing flight did not differ significantly between the groups, though acute uptake of 250 ppb thiacloprid resulted in a significant higher percentage of bees that did not return to the hive. Concluded, sublethal doses of the neonicotinoid thiacloprid appear to delay the behavioral development of honeybees and may interfere with their navigational capacities.

17

2.5 Interactions between microsporidia, viruses and pesticides in larvae and adult honey bees - Interaktionen zwischen Mikrosporidien, Viren und Pestizide bei ihrem Einfluss auf Larven und erwachsenen Honigbienen

Vincent Doublet, M. Labarussias, M. E. Natsopoulou, J. Steinberg, A. Miertsch, J. R. de Miranda, R. J. Paxton (Halle, Allg. Zool., Uppsala)

There are many factors that can precipitate the decline and death of honeybee colonies. What is less-well known is how these factors affect each other. In recent studies, focus has been placed on the interactions among several potential ‘stressors’, and particularly on the interaction between disease-causing microorganisms and sub-lethal doses of pesticides. Our research investigated how the interactions among pathogens and pesticides affect individual honey bees. We studied these interactions both in adults, with cage experiments, and in larvae using in vitro rearing techniques, using the microsporidian Nosema ceranae, a common virus (black queen cell virus - BQCV) and a widely used insecticide (Thiacloprid), fed to larvae and adults at sub-lethal doses. We detected multiple interactions during our experiments. In larvae, we observed an interaction between the BQCV and Thiacloprid that affected both survivorship and development (pupation). In adults, interactions between the virus and the insecticide were also observed, but to a lesser extent than between N. ceranae and Thiacloprid, suggesting that these two pathogens interact differently with the pesticide or induce a different response in the honey bee. The interaction that led to the greatest impact on honey bee mortality was that between BQCV and N. ceranae. Co-infected adult bees had a much higher mortality than all other treatments, suggesting a synergistic interaction between these two pathogens. These observations support the idea that co-infection by multiple pathogens could be a significant factor of honey bee decline. However, the causal mechanisms of the interaction between them are still unclear. We acknowledge support of the EU (project: Bee Doc) and the BMELV/BLE (project: Fit Bee).

2.6 Synergistic effects of Nosema ceranae and sublethal doses of Thiacloprid, τ-Fluvalinate and Clothianidin on bees (Apis mellifera L.) in mating hives - Synergistische Effekte von Nosema ceranae und subletalen Dosen von Thiacloprid, τ-Fluvalinat und Clothianidin auf Bienenvölker (Apis mellifera L.) im Kieler Begattungskästchen

Richard OdemerS, T. Stahl, P. Rosenkranz (Hohenheim)

Interactions between bee diseases, varroacides and pesticides are considered a crucial driver of colony losses. In our experimental approach we used mating nucs containing 700 - 1,000 honeybees in order to examine synergistic long-term effects on the colony level. Freshly hatched and individually marked bees were treated with the neonicotinoids Thiacloprid and Clothianidin and the synthetic pyrethroid τ-Fluvalinate, either as single

18

applications or as combination of all components. Additionally, some of the insecticide treated bee groups were infected artificially with Nosema ceranae. Twenty four hours after the treatment, the bees (n=80 bees per group) were introduced into small colonies (n=6). The numbers of marked bees were counted daily for a period of four weeks. Additionally, the flight activity of marked bees was recorded several times per day. The application of sublethal dosages of insecticides did not reveal clear significant effects on the longevity and flight activity of the bees. However, N. ceranae infected bees showed higher mortality rates and a somewhat higher flight activity. Synergistic effects of Nosemosis in combination with pesticide application could not be verified. Our results confirm studies from previous years of our working group and of cooperation partners in Bern (Switzerland), but disagree with some recent publications. The possible reasons for this discordancy are discussed.

Supported by the EU project "BEE DOC" (244,956 CP-FP)

3. Physiologie & Verhalten 3.1 Trans-generational immune priming in honeybees - Generationsübergreifende Immunisierung bei Honigbienen

Javier Hernández-LópezS, W. Schuehly, U. Riessberger-Gallé, K. Crailsheim (Graz)

Maternal immune experience acquired during pathogen exposure and passed on to progeny to enhance resistance to infection is called trans-generational immunity (TI). In honeybees, TI would result in a significant improvement of health at individual and colony level. Demonstrated in invertebrates other than honeybees, TI has not yet been fully elucidated in terms of intensity and molecular mechanisms underlying this response. Paenibacillus larvae (Pl) is a spore-forming Gram-positive bacterium causing American Foulbrood, the most deadly bee brood disease worldwide and the spores are the infectious stage of this pathogen. Here, we immune-stimulated honeybee queens by injection of heat-killed bacteria of (Pl) and a control group was injected with Ringer solution. Offspring of both treated queens were artificially reared and exposed to a load of c. 20 spores of Pl per larva. Subsequently, mortality rates were measured daily for twelve consecutive days to evaluate maternal transfer of immunity. A strong increase in resistance of c. 25% to AFB infection was found among offspring of the Pl-challenged queens as compared to the Ringer-injected control group. Our data substantiate the existence of trans-generational immune priming in honeybees by direct evaluation of offspring resistance to bacterial infection revealing an experience-dependent maternal effect on offspring immunity. Due to the enormous industrial and ecological importance of honeybees, this maternal transfer of immunity could translate into an enormous advantage for a colony and have a significant practical benefit for the beekeeping industry (e.g., the development of immunization programs in apiculture).

19

3.2 Dose-dependent effects of transgenic pollen on honey bee larvae - Dosisabhängige Auswirkungen transgener Pollen auf Honigbienenlarven

Karin SteijvenS, I. Steffan-Dewenter, S. Härtel (Würzburg, Zoo III)

The honey bee is the most comprehensively studied insect species, and more importantly, it provides a vital ecosystem service by pollinating both wild plants and crops. This makes the honey bee an excellent model species for Environmental Risk Assessments (ERA) evaluating risks on non-target arthropods. Several ERA studies on transgene crops have addressed their effects on adult bees; however most genetically modified crops have been designed to affect the larval stage of pest insects, as this is the development stage that negatively impacts the crop. Therefore, we tested the effects of Bt maize expressing three different insecticidal proteins on honey bee larvae in a standardized in vitro larvae rearing system. We used a stacked Bt maize variety and compared it with several negative controls where we expected no effects (near-isogenic line, another non-transgene maize variety, and multi-floral pollen) and a positive control (toxic pollen). In vitro reared larvae were fed a range of pollen-dosages between 0 and 10 mg within each pollen treatment. We measured the larval mortality, weight and development, and quantified the digestibility of the different pollen types. The results of this study will contribute to the safety of transgenic crops for honey bees.

3.3 Experiments on the choice of water foraging honeybees (Apis mellifera L.) under semi-field conditions - Versuche zum Wahlverhalten von Wasser sammelnden Bienen (Apis mellifera L.) im Halbfreiland

Jana ReetzS, K. Wallner (Hohenheim)

Acquiring information about the behaviour of water foraging bees (Apis mellifera L.) between different qualities of water under field conditions is difficult due to the wide foraging range. Therefore, semi-field experiments were conducted to examine the honeybee’s water collection behaviour by having the choice between pure water and water contaminated with different levels of clothianidin (10, 50, 100 and 150 ng/ml). As a control, water was tested against water. Each of the four tents included two water stations and a feeding station, where pollen and sugar was offered. Additionally sugar dough was offered within the beehives to increase the water demand of the colonies. To exclude natural water sources and vegetation within the four tents, the ground has been covered by shade cloth. In preparation for each trial, the solution of both water stations of each tent was substituted by freshly water and test solution, respectively. The solutions were used in blind application and simultaneously in the four tents. To evaluate the collecting behaviour of honeybees between different water qualities, the number of bees drinking at each water sources was counted for two hours in intervals of 15 minutes. In total, 16 trials for each test solution were performed.

20

These semi-field experiments revealed that water foraging honeybees showed no reaction to the quality of test solution while having the choice between pure water and water contaminated with clothianidin. None of the water qualities was completely avoided. No definitive thresholds for a time interval after exposure or a concentration level could be measured.

3.4 Proteins of royal jelly: evolution and function in social insects - Proteine des Weiselfuttersaftes: Evolution und Funktion bei den sozialen Insekten

Stefan Albert, J. Spaethe, K. Grübel, W. Rössler (Würzburg, ZOO II)

Royal jelly is a secretion produced by nurse honeybees. Extensive feeding of royal jelly triggers the development of larvae into queens instead of workers. The vast majority (>90%) of the proteins of royal jelly are closely related to each other. Nine MRJP (major royal jelly protein) genes were found in the honeybee genome. We hypothesized that MRJPs arose via repeated duplications of a single originator, which accompanied the evolution of a (eu)social brood feeding behavior. However, the identification of multiple MRJP-like genes in distantly related Hymenoptera species such as ants or the parasitoid Nasonia contradicts the unique and social feeding-associated origin of MRJP multiplication. Although analyses suggested that multiplications in the honeybee, ant and Nasonia lineages occurred independently, evidence of a “transition species” with a single MRJP gene was missing. By using a comparative approach including other bee species, we found that bumblebees bear only one copy of MRJP-like gene and thus might constitute such a transition species. In order to identify the original function of MRJP, we explored the MRJP expression pattern in bumblebee worker, male and queen by means of real-time PCR and immunohistochemistry using a MRJP-specific antibody. We found support for a dual function of MRJP in bumblebees. As (1) a component of the hypopharyngeal gland secretion it might participate in food processing, and (2) in Kenyon cells of the brain it possibly participates in processing of neuronal information. 3.5 Fertility of honeybee workers is mediated by Epidermal Growth Factor Receptor (EGFR) - Die Fruchtbarkeit von Honigbienenarbeiterinnen wird durch EGFR (Epidermaler Wachstumsfaktor Rezeptor) vermittelt

E. M. Formesyn, D. Cardoen, Ulli ErnstS, E. Danneels, M. Van Vaerenbergh, D. De Koker, P. Verleyen, T. Wenseleers, L. Schoofs , D. C. de Graaf (Ghent, Leuven)

One of the hall marks of eusociality is reproductive division of labour. In honeybees (Apis), the queen lays virtually all eggs, whereas workers usually remain functionally sterile. However, workers can readily activate their ovaries and become fertile under queenless conditions. Worker bees regulate their fertility dependant on their social environment,

21

including pheromones of both queen and brood. Yet, how these signals and cues are processed, and how this translates into sterility or fertility, is not known. Understanding how fertility is regulated will provide deeper insight in the molecular architecture underlying the evolution of eusociality. Using RNAi in caged queenless worker bees, we show that Epidermal Growth Factor Receptor (EGFR) is involved in regulating worker fertility. As EGFR is also mediating whether larvae develop into queens or workers, this suggests that both worker fertility and caste determination partly rely on the same regulatory networks.

3.6 Conditioning of honeybee colony on TNT and DNT scent - Konditionierung von Honigbienen Völkern auf TNT und DNT Duft

Nikola Kezić, M. Janeš, J. Filipi, M. Dražić, K. Crailsheim, Y. Leconte, N. Pavković (Zagreb, Knin, Graz, Avignon)

Experiment was focused on the conditioning of the Apis mellifera carnica colony to search for DNT and TNT scent in controlled environment. After preparation of the testing mesh tent and feeders, 10 training and testing trials were performed. Majority of the experiments was carried out in a period from April to July 2012. For the training and testing of bees, artificial targets were designed. Six observers counted bees crossing and/or lending on the six targets, from which three targets were with and three without scent (control). Crossing bees were counted in the area of 20 cm above the target. Landing bees need to touch or sit on any part of the target. In average, 29.22 bees were crossing above TNT and 28.69 bees above control targets. The average number of landing bees was 9.72 on TNT and 2.78 on controls. When the target scent was DNT, in average 61.19 bees were crossing targets, and 42.64 controls. Results were more distinct in landing on DNT, when in average 40.42 bees landed on target with scent in comparison to 2.91 bees on controls. The number of bees recognizing DNT was higher in comparison to TNT due to its more intense smell. These results indicate that bees from trained colony can clearly distinguish target with odor by lending on it.

3.7 The upper lethal temperature of Apis mellifera carnica and A. m. ligustica - Die obere Lethaltemperatur von Apis mellifera carnica und A. m. ligustica

Helmut KovacS, A. Stabentheiner, C. Costa (Graz, Bologna)

The two subspecies of the western honeybee Apis mellifera carnica and Apis mellifera ligustica are closely related and live in neighboring climatic regions. The Carnolian bee is the honeybee of the temperate Central European climate region and the Ligustica bee is original native to the Mediterranean South European climate region. We investigated whether these two subspecies developed adaptations to their local climate conditions and differ in their thermal traits.

22

For conducting the experiments 10 to 20 forager bees of each of the two races were caught after leaving the hive and were put separately in a divided cage and transferred into an incubator. Starting with an initial temperature of 30 °C, the temperature was increased at a rate of 0.4 °C per minute to a maximal temperature between 46 °C and 56 °C. When the maximal temperature was attained, they remained for five minutes at this temperature. Afterwards, the temperature was quickly reduced to 30 °C and the bees stayed for further eight hours in the incubator. Then the numbers of living and dead bees were counted. A total of 19 trials were performed in this way. During experiments the bees were provided with 1 M sucrose solution. The mortality was plotted in dependence on ambient temperature and from the obtained sigmoidal curves the temperature was determined, where 50% of the bees were still alive (lethal temperature = LT50). The LT50 was 1.3 °C higher in the Ligustica bees and significantly different between the two subspecies (Carnica: LT50 = 50.4 °C; Ligustica: LT50 = 51.7 °C; p<0.02; ANOVA). These results show that the two closely related subspecies differ in their thermal traits. The South European race is well adapted to the higher extreme temperatures in the South European climate region. 3.8 Advances in the cryopreservation of honey bee drone semen - Fortschritte bei der Kryokonservierung von Drohnensperma

Jakob Wegener, T.May, G. Kamp, K. Bienefeld (Hohen Neuendorf, Mainz)

The cryopreservation of drone semen could potentially be a useful tool for reducing inbreeding, accelerating genetic progress, and conserving intraspecific biodiversity. Its practical application has been hampered by the limited fertility of frozen-thawed semen. Sperm in ejaculates are densely packed with mostly parallel axonemes. This structure is partly destroyed when semen is mixed with freezing diluents. Another problem is that dimethyl sulfoxide (DMSO), the cryoprotectant usually used for freezing of drone semen, has been found to be toxic to sperm and/or queens. Here we report on the results of new cryoprotocols, which aimed to reduce the disruption of sperm-sperm interactions by either the fast admixture of only a small volume of highly concentrated (50% v/v) DMSO (treatment “admixture”), or by dialysis of semen against a hypertonic HEPES-buffer with 22.5% DMSO (treatment “dialysis”). In a third treatment (“dialysis + washing”), DMSO was added through dialysis and partly removed from thawed semen by washing with HEPES-buffer. Queens inseminated with semen that had been cryopreserved in these three ways showed 45.7% (“admixture”), 47.5% (“dialysis”), and 27.0% (“dialysis + washing”) female offspring (n = 12, 11, and 11). In the “dialysis”-group, numbers of sperm reaching the spermatheca were higher (799.000) than with any protocol previously published, though still much lower than those typically obtained with unfrozen semen (approx. 3 to 5 million). Worker offspring appeared normal in all treatments, with fluctuating asymmetry of ovariole numbers (left-right ovary) not significantly different from that in workers from normal inseminations (ANOVA; total n = 150; df = 3; F = 1.20; P = 0.31). These results show that cryoprotocols using dialysis to add cryoprotectants are a promising way of improving fertility of frozen-thawed semen.

23

4. Bienenpathologie 4.1 Coordinated treatment of Varroa destructor to reduce reinvasion - Koordinierte Bekämpfung von Varroa destructor zur Reduktion der Reinvasion

Jochen Pflugfelder (Liebefeld) Variable treatment efficiency and reinvasion of Varroa destructor from infested hives in the neighbourhood are the main reasons for the frequent high colony losses. It has been shown that reinvasion can be as high as 300 mites per day in the late season over distances up to 2 km. Reinvasion is an important survival mechanism of the mites when the parasitized colony collapses. In a field trial the efficiency of an area wide V. destructor treatment in about 800 colonies (167 bee yards) was investigated in the canton of Berne (154 km2). In early August 2012 100% of the colonies within a circle of 14 km diameter were treated simultaneously either with formic acid or thymol products. As control we used about 800 colonies situated within a ring area of 3 km surrounding the circle, in which colonies were treated around the same date but treatments were spread over a time interval of about 4 weeks in accordance to beekeepers’ habitual schedules. We here report on the efficiency of this coordinated treatment, the mite reinvasion and the winter survival of the colonies in comparison with control area. 4.2 Function and efficacy of the Varroa-Gate, a device in the hive entrance for the control of Varroa destructor infestations in honey bees - Funktion und Wirkungsweise des Varroa-Gates, einer Fluglochapplikation zur Kontrolle von Varroa destructor Infestationen bei Honigbienen G. Koeniger, Nikolaus Koeniger, B. Grünewald, K. Krieger (Oberursel, BAYER/Monheim) Bei dem Varroa-Gate handelt es sich um einen Polymermatrix-Wirkstoffträger, der bündig im Flugloch der Bienenbeute angebracht wird. Es stellt eine Barriere dar, die den Bienen eine Passage nur durch eines seiner zahlreichen Löcher ermöglicht. Anzahl und lichte Weite der Löcher wurden auf die Größe der Bienen (Arbeiterbienen und Drohnen) und die Anforderungen an den Luftaustausch abgestimmt. Die Wirkstoffabgabe im Varroa-Gate erfolgt durch den Kontakt der ausfliegenden oder heimkehrenden Bienen mit dem Wirkstoffträger und nicht etwa durch Verdampfung. Wie bei Käfigversuchen im Labor gezeigt wurde, wird dabei die auf der Biene befindliche Milbe vom Wirkstoff erreicht und in den folgenden 24h bis 48h abgetötet. Im Falle von zurückkehrenden Bienen wird so die Einschleppung von Milben aus der Umgebung unterbunden und das Varroa-Gate kann, nach einer effektiven Behandlung der Varroose eingesetzt, den dabei erzielten

24

Behandlungserfolg sichern. Fliegt eine parasitierte Biene aus dem Volk heraus, so wird auch diese Milbe bei der Passage eliminiert. Damit führt das Varroa-Gate zu einer Verminderung der im Volk vorhandenen Milben. Natürlicherweise wird die Flugaktivität eines Bienenvolkes von den Trachtbienen dominiert. Das sind Bienen, die meist älter als 20 Tage sind und die als Wirtsbienen für Varroa destructor nicht besonders attraktiv sind. Eine Elimination von phoretischen Milben auf Flugbienen allein würde vermutlich – über die bereits oben beschriebene Verhinderung einer Re-infektion hinaus – nur eine unerhebliche Reduktion der Milbenpopulation im Bienenvolk bewirken. Unsere Versuchsergebnisse (in Florida und Oberursel) zeigen jedoch einen hohen Wirkungsgrad. Zwischen 85% und 99% der Varroa destructor Population im Bienenvolk wurden durch den Einsatz der Gates vernichtet. Wir präsentieren diese Versuchsergebnisse und diskutieren mögliche Ursachen für die gefundene hohe Wirksamkeit. 4.3 Do not fight against Varroa - get rid of it! - Warum Varroa bekämpfen, wenn Bienenhaltung ohne Varroa möglich ist? Heikki M.T. Hokkanen & I. Menzler-Hokkanen (Helsinki) In order to develop sustainable apiculture in Europe, and in particular to deal with the Varroa problem, we need fundamentally new approaches. Varroa has been in Europe for decades, and has been thoroughly researched for over 30 years, with only limited success in containing the plague. The best tool we have at hand is to continuously rely on pesticides and other undesired intervention methods. We propose to focus on developing Varroa-free apiculture. While in other agricultural disciplines it has long been recognized and practiced to start new cultures with disease-free materials, to our knowledge this has not been the approach in apiculture. We will develop and test apiculture model, where apiaries are started with Varroa-free (and if possible, disease-free) nucleus colonies, and to renew them after disease pressure develops too high. If this is practiced over larger areas, or in confined environments such as islands, the disease-free apiculture may persist for a long period. Many large beekeeping operations in the world are functioning with new nucleus colonies as a starter every year; New Zealand is a large supplier of nucleus colonies to the rest of the world. However, these are not disease or Varroa free, but rather serve as source of many diseases. We will initiate the production of Varroa-free starter colonies in parts of Finland, which still are Varroa-free. In addition we will select a production site, where there is no beekeeping at all, naturally isolated from any external sources of infection. Colonies will be reared on new, disease free housing, frames, and other equipment and the first colonies will be reared from clean, disease free sources. The first new ”SaniBee®” starter colonies will be ready for testing in the spring of 2014, and can be obtained from us to a limited extent by interested colleagues. In the field the development of the colonies will be monitored, and they will be regularly tested for diseases and Varroa, to study the pick-up rate of diseases in the field.

25

4.4 DWV/VDV-1 and overwinter colony losses in Germany - DWV/VDV-1 und Winterverluste bei Honigbienenkolonien in Deutschland

Myrsini E. NatsopoulouS, D. P. McMahon, V. Doublet, V. Maibach, E. Frey, P. Rosenkranz, R. J. Paxton (Halle, allg. Zool., Hohenheim)

Winter mortality is a prime cause of colony loss in Europe, and honey bee colonies suffering elevated worker losses over winter are likely to be more prone to collapse. To explore an explicit cause of colony decline during winter, workers from colonies either treated or untreated in autumn to control Varroa destructor were sampled in autumn 2011 and the following spring 2012. We used a PCR-based multiplex ligation analysis (MLPA) to monitor the presence/absence of seven viral targets as well as Nosema spp. Levels of overwinter worker mortality within their colonies were also recorded. Quantitative RT-PCR was used to assess infection level of the most prevalent pathogens in pooled and individual samples of worker bees. Preliminary analyses indicate that autumn 2011 honey bees carried a heavy burden of VDV-1 (biologically close to DWV) and BQCV independent of Varroa-treatment but, in spring 2012, the level of VDV-1 in workers was low, suggesting that infected workers had died during the winter. Conversely, BQCV titres in workers did not change between seasons. Untreated colonies suffered higher worker losses compared to treated colonies. In order to corroborate our hypothesis derived from our field observations that the DWV/VDV-1 family of viruses has a significant impact on honey bee winter morality, we used a controlled laboratory experiment to inject autumn bees with DWV/VDV-1. Our results support the notion that DWV and related viruses are a major cause of worker mortality and colony collapse. We acknowledge support of the BMELV/BLE (project: Fit Bee), the EU (project: Bee Doc) and the BBSRC’s Insect Pollinators Initiative (project: Emergent Diseases).

4.5 Comparison of colony health in wild and managed honeybees - Vergleich des Virenbefalls zwischen wilden Honigbienen und Imkerbienen

Matthias Y. MuellerS, B. F. Kraus, R. F. A. Moritz (Halle, Mol. Ökol.)

Apiculture is assumed to increase colony density and to reduce genetic diversity and therefore promote pathogen transmission. To investigate this hypothesis it is necessary to compare the health status of truly wild honey-bee populations with managed ones. The Cape region in South Africa is one of the very few areas in the world where untouched honeybee populations coexist with apiculture. In this study, we screened several honeybee populations of that region for prevalence of six different viruses. We used a new diagnostic MLPA tool (Multiplex Ligation-dependent Probe Amplification, “Beedoctor”, de Smet et al. 2012) to test bees from nature reserves and apiaries. Furthermore we determined population genetic parameters to assess genetic diversity of these populations. Despite of a higher genetic diversity, managed honeybee population

26

had higher rates of infections compared to the wild population. Thus, the high colony density at apiaries which makes it easier for pathogens to spread seems to nullify the advantage of a higher genetic diversity.

4.6 Comparison of the efficacy of Formic Acid 60% and 85% as Varroa treatment applied in two different evaporation systems - Vergleich der Wirksamkeit von Ameisensäure 60% und 85% zur Varroabekämpfung in zwei verschiedenen Verdunstungssystemen

Peter Rosenkranz, P. Aumeier, S. Berg, O. Boecking, R. Büchler., W. Kirchner, T. Kustermann, C. Otten, A. Reichart, W. von der Ohe (Bochum, Celle, Hohenheim, Kirchhain, Mayen, Veitshöchheim)

Formic acid (FA) is an indispensable component of integrated Varroa treatment concepts in Middle and Northern Europe. To ensure a high efficacy and to prevent side effects on brood and bees a uniform evaporation of the acid over a distinct time period is required. We compared two different concentrations of FA applied in two evaporators commonly used in Germany (Liebig-Dispenser (LD); Nassenheider evaporator (NH) horizontal/ vertical). Two FA treatments were performed in August and September, respectively, using a total of 156 test colonies in one and two story hives at apiaries of 6 apicultural institutes. Depending on FA concentration, size of the hives and evaporator type we applied between 50 and 280 ml FA solution per treatment. Based on a standardized protocol, we present data on the population dynamic of the colonies, the efficacy of two consecutive FA treatments, the evaporation rates and side effects (queen losses, bee mortality). The total Varroa infestation – calculated from the FA plus the control treatments - varied between a few hundred and more than 10,000 mites per colony without significant differences between the treatment groups (p>0.05; Kruskal Wallis). Likewise, we could not detect any significant differences in the efficacies of the FA treatments (calculated in relation to control treatments with Bayvarol and Oxalic acid) according to FA concentration, evaporation type and size of the hive (exception: NH vertical). The average within group efficacies ranged from 93% - 98% with only few outliers. The absolute numbers of mites killed by the control treatments after two FA treatments were remarkable low with a range from 11 to 207 (n=95). The number of dead bees in the death traps during the FA treatments revealed high differences between colonies, however without significant group specific differences. In our experiments we could therefore not confirm a higher efficacy of FA 85% compared to 60%. The possible reasons for this unexpected result will be discussed.

27

4.7 Infestation of midgut epithelium in Nosema tolerant and susceptible honey bee strains towards N. ceranae infections - Infestation des Mitteldarm Epitheliums in Nosema toleranten und anfälligen Honigbienen Stämmen bei N. ceranae Infektionen

Q. Huang, Christoph KurzeS, R. F. A. Moritz (Halle, Mol.Ökol.)

The microsporidian Nosema ceranae is a natural parasite of the Asian honeybee Apis cerana but is now also a widespread cause of Nosemosis in the European honey bee A. mellifera. N. cerana infections can have severe effects on honey bee fitness at the individual and colony level. We found that the extensive breeding effort by Danish beekeepers against the native microsporidian parasite N. apis has produced a Nosema tolerant honey bee strain, which revealed a strongly up-regulated immune response when challenged by N. cerana infection compared to an unselected strain. After transmission via the fecal-oral route, spores normally germinate in the midgut, where they penetrate, replicate and destroy the cells of the gut epithelium. To understand the effect of the altered immune response on the level of infestation and destruction of the midgut epithelium, we compare sections between the selected and an unselected strain over the course of infection. We discuss these results in the context of an adaptive immune response and other underlying biological mechanisms of the selected strain against N. ceranae infection.

4.8 Winter mortality, varroa control, viruses, Nosema spp., a retrospective study 2010-2012 in the Netherlands – Winterverluste, Varroakontrolle,Viren und Nosema, eine retrospektive Studie 2010-2012 in den Niederlanden

Sjef van der Steen, B. Cornelissen, C Hokahin (Wageningen)

Winter mortality has multiple causes varying from pathogens, beekeepers practice to pesticides. To study correlations between winter mortality, varroa control and pathogens, a retrospective study was done. Beekeepers were asked to sample three colonies in May and the same colonies in September 2010 and again in 2011. To do this, they were provided with sampling kits and sample instructions. The samples were sent to the lab and stored at -20 oC. In spring 2011 and 2012 the beekeepers were asked to e-mail us the overwintering of the three colonies sampled both in Mai and September. In 2011 and 2012, the Mai and September samples of the colonies that did not survive winter and samples of an ad random selection of colonies that survived winter were checked for varroa mites; the prevalence of Nosema apis, Nosema ceranae, DWV and ABPV of the year preceding the winter mortality was recorded qualitatively by Taqman PCR. Data on the apiary winter mortality and varroa control in 2010 and 2011 of the participating beekeepers were obtained from the NCB. Analysis of pesticides was not included in this study. The results of the period 2010-2011, based on 21 colonies that did not survive winter and

28

22 colonies that did survive winter and 50 participating apiaries, showed no correlation between winter mortality and the presence of Nosema ceranae, Nosema apis, DWV and ABPV. Varroa control in July-August correlated with a successful winter survival. Winter mortality seemed to be apiary related; the mean mortality in apiaries that reported yes and no winter mortality of the three test colonies was 35% and 18% respectively. In spring and September samples Nosema ceranae and Nosema apis were recorded in 80% and 15% and 40% and 30% respectively. DWV and ABPV was prevalent in about 100% and 30% in the Mai samples and in 90-100% and 40-50% in the September 2010 samples respectively. These results, the results of the period 2011-2012 and the overall finding will be presented.

4.9 Different strategies of Paenibacillus larvae to evade the immune response of honey bee larvae - Verschiedene Strategien von Paenibacillus larvae die immune Reaktion der Honigbienenlarve zu umgehen

Gillian HertleinS, L. Poppinga, E. Garcia-Gonzalez, A. Fünfhaus, K. Hedtke, E. Genersch (Hohen Neuendorf)

Honey bees are among the most important productive livestock due to their indispensable role as commercial pollinators of many agricultural crops and fruit. Therefore, maintaining honey bee health and mitigating honey bee diseases is crucial for human food production and security. The epizootic American Foulbrood, caused by Paenibacillus larvae, is a fatal bacterial disease of honey bee brood able to kill entire colonies which leads to considerable losses in global apiculture every year. We recently identified and characterized four genotypes of P. larvae (ERIC I-IV) which differ in virulence, i.e. death of the infected larvae and collapse of diseased colonies proceed at different rates. First results on the molecular pathogenesis of P. larvae infections revealed that ERIC I and ERIC II developed different strategies to kill infected larvae. It has been shown that honey bee larvae mount an immune response against P. larvae infection by up-regulating expression of several antimicrobial peptides (AMP). We now show that this up-regulation also differs between the P. larvae genotypes with the fast-killing genotype ERIC II triggering a weaker immune response than the slowly killing genotype ERIC I. We hypothesize that the ERIC II-specific S-layer protein helps the bacteria to evade the larval immune system. In addition, ERIC II exclusively expresses immune inhibitor A (InhA), a protein known to be involved in AMP-degradation. Knock-out mutants for InhA show significantly reduced mortality in exposure bioassays suggesting that InhA plays an important role during pathogenesis of P. larvae infections.

29

4.10 Annotation of genes encoding G-protein-coupled receptors for biogenic amines in the parasitic mite Varroa destructor- Annotation von Genen für G-Protein-gekoppelte Rezeptoren für biogene Amine in der parasitischen Milbe Varroa destructor Sebastian WernigS, Wolfgang Blenau (Oberursel) The parasitic mite Varroa destructor is the central pest of the western honey bee Apis mellifera. Without treatment, a significant mite infestation will lead to the death of the honeybee colony. Varroa destructor is the parasite with the most pronounced economic impact on the beekeeping industry. It is a major contributing factor to Colony Collapse Disorder which is threatening hives in the USA and constitutes a severe problem in beekeeping worldwide. In order to advance our understanding of Varroa biology and to identify new avenues for mite control, the Varroa Genome Project was initiated in 2010. We screened the genomic sequence of the Varroa mite for the presence of genes coding for G-protein-coupled receptors (GPCRs) for biogenic amines. Biogenic amines and their receptors are very important because they occupy a high hierarchic position in the physiology of arthropods and control or modulate crucial processes such as development, reproduction and behavior. Furthermore, GPCRs (for octopamine and tyramine) are believed to be the molecular targets of formamidine acaricides such as amitraz and of plant essential oil constituents such as thymol. A total of 16 putative aminergic GPCR genes were identified. Phylogenetic analysis showed that 14 of them are closely related to insect GPCRs, which allowed the prediction of their putative ligand in 11 cases with varying degrees of certainty. Interestingly, two Varroa destructor GPCRs have no identifiable orthologs in the genomes of any insect species. One of them is most closely related to deuterostomian α1-adrenergic receptors whereas the other is similar to metabotropic histamine H1 receptors (which are not present in insects).

5. Bienenprodukte & Sonstiges 5.1 Comparison of new computer methods for honeybee colony assessments - Ein Vergleich neuer Bildverarbeitungsmethoden zur Abschätzung der Koloniegröße von Honigbienen

Magnus Wang, L. Brewer (Heidelberg)

Colony assessments are an important method for the evaluation of the development and health of honeybee colonies. They are also routinely used to monitor the development in field trials focusing on effects by pesticides. Currently, colony strength is usually estimated visually, e.g. using the “Liebefelder” estimation method. While this method is quick and easy to conduct in the field, it is only a rough estimate of the colony size and

30

individual variation between field staff can be rather strong. Due to practical reasons individual counting of honeybees is not feasible. However, recent computer methodologies based on digital images offer less time consuming evaluations. We therefore tested different computer methods for colony strength estimation and compared them to currently used methods.

5.2 The same procedure as every year? Comparison between the years 2011 and 2012 of FitBee Module 5 - Gleiche Ergebnisse bei gleicher Vorgehensweise? Vergleich 2011 & 2012 des FitBee Moduls 5

W. von der Ohe, Dorothee J. Lüken (Celle)

Das Kooperationsprojekt FitBee (BLE, BMELV) geht mit der Auswinterung 2012/2013 in die dritte Runde. Somit ist die Möglichkeit gegeben, die Ergebnisse der ersten beiden Jahre miteinander zu vergleichen. Während der Bienensaison 2011 sowie auch 2012 standen Bienenvölker an Standorten mit unterschiedlichen Standortfaktoren: Gruppe A stand an landwirtschaftlichen Nutzflächen mit guter Nektarversorgung im Frühjahr und an Standorten mit schlechter Nektarversorgung im Sommer und Herbst, Gruppe B an blühenden Agrarflächen im Frühjahr, an Blühstandorten mit hoher Diversität im Sommer, beide mit guter Nektarversorgung, aber an landwirtschaftlich genutzten Flächen im Herbst mit schlechter Nektarversorgung. Gruppe C hatte eine große Blühvielfalt mit guter Nektarversorgung über das gesamte Jahr zur Verfügung. Regelmäßig wurden Populationsschätzungen durchgeführt, neben Bienenproben wurden Bienenbrotproben sowie Honigproben genommen, 2012 wurden zusätzlich Pollenfallen eingesetzt. Wie unterscheiden sich die Jahre im Hinblick auf den Pollen- und Nektareintrag sowie den damit verbundenen Eintrag von Pflanzenschutzmittelrückständen? Können schon allgemeingültigere Aussagen über die verschiedenen Standorte gemacht werden? Grundsätzlich waren die beflogenen Pflanzen über den Jahresverlauf an den verschiedenen Standorten zwischen den Jahren ähnlich, dennoch haben sich ganz klar Änderungen in der Nutzung von Agrarflächen in den Pollenanalysen abgezeichnet. In den Bienenbrotproben wurden im Jahr 2011 25 verschiedenen Wirkstoffe gefunden und im Honig ein Wirkstoff, 2012 waren es 36 verschiedene Wirkstoffe im Bienenbrot, bzw. Pollen aus der Pollenfalle und wiederum wurde nur ein Wirkstoff im Honig analysiert. Für die Auswertung der Populationsschätzungen befindet sich mit dem Projektpartner IP SYSCON eine Datenbank im Aufbau, die Teil eines Fachinformationssystems für Imker sowie weiteres interessiertes Fachpublikum werden wird.

31

5.3 Is drone brood removal an efficient treatment against Varroa? – Ist die Entnahme von Drohnenbrut eine effiziente Methode gegen Varroa?

Manuel Tritschler (Monheim)

Control of Varroa destructor is becoming more and more of a challenge for beekeepers worldwide. In this context, a lot of research has been carried out previously and is currently being undertaken to find solutions to control this ectoparasite. Beekeepers are offered a wide variety of different Varroa treatment options. In order to obtain a better understanding of how best to control Varroa, three different drone brood methods were applied in beehives and observed in the study outlined here. The aim was to investigate the efficacy of drone brood removal as an element of an integrated Varroa control concept with organic, natural and also synthetic chemical treatments over the whole season. The experiment began in early April, 2012, when the first flight activities of the colonies started. Fifteen colonies were included in the investigation, divided into three groups and situated at two different sites under the same climatic conditions. Five of the colonies were set up with two drone brood frames, five colonies used only one drone brood frame and the remaining five were set up without drone brood frames. The observation period ran for more than 12 weeks, mite counts on the sticky board of each colony were recorded weekly. Once a fortnight, the newly capped drone brood frames were removed from the colonies where they had been used and replaced with new frames. This ensured that no hatching of drones would take place in the colony. In order to detect the mites which still remained in the colonies at the end of the study, the colonies were treated three times with formic acid in August and the mites which dropped to the floor were also counted. The colonies without drone brood frames, did not survive the winter. The results demonstrate that regular removal of drone brood frames, to prevent hatching, is a highly efficient and important part of the whole treatment program against Varroa during the year.

5.4 The polliantor discussion in Brazil - consequences for us - Die Bestäuber-Diskussion in Brasilien – Konsequenzen für uns

Wolf Engels (Tübingen, São Paulo)

The Encontro sobre Abelhas is organised by the University of Sao Paulo every second year in Ribeirao Preto. This international congress with over 400 participants from many countries treated the worldwide decline of pollinators as a main topic. Vera Imperatriz-Fonseca presented a volume of c. 500 pages entitled “Polinizadores no Brasil” – pollinators in Brazil. In 23 contributions of 90 authors the actual situation and the development since the Eco Summit 1992 in Rio de Janeiro is described. The global

32

dimension of the problem was released by the ongoing international discussion on losses of honeybee colonies, with focus on the situation in the USA. In particular the pollination service with long distance transports of package colonies is involved. The impact resulted already in a rise of prices for almond, blueberries and other products of the fruit industry. But not only managed honeybee colonies are involved, but in general the biodiversity of wild bees, for instance bumblebees and in the tropics stingless bees. As documented in the last years, about 75% of human nutrition depends directly or indirectly on pollination of angiosperm plants. This basic link between pollinators and agriculture, but also conservation of nature is fact for the scientific community, but far from political consequences. In Brazil, the “Sao Paulo Declaration on Pollinators” was published already in 1999. On the blurb of the recent book publication Braulio Dias, Secretary of the Brazilian Federal Ministry of Environment and active in international conservation institutions, called for more research. National activities like In Brazil are imperative. We should initiate this in Germany and also in the European Community.

5.5 Effective harvesting methods for propolis in Germany: A field-trial Effektive Propolisernte in Deutschland: Ein Praxistest

Nadine KunzS, A. Schroeder (Hohenheim)

In contrast to tropical regions and Eastern Europe, the quantities of propolis harvested in Germany are considered to be very low. Furthermore, a general quality standard for harvested propolis is lacking. The aim of this field-trail was to establish an effective method of propolis harvesting in colonies of Apis mellifera in order to yield a high quantity and quality of propolis with low handling time and without negative impact on the colony. Several methods and harvesting tools were tested and compared during the summers of 2008, 2009 and 2010 in a total of 185 colonies at 16 locations in Southwest Germany. Six beekeepers participated in the project. They worked with free mated honey bee colonies of different genetical origin. We tested glas, plastic and wooden grids (n=7), store-bought and purpose-build. The efficiency was calculated on 176 data sets from 2010 by comparing quantity (weight), different parameters of quality (e.g. balsam content, sensory evaluation, flavonoid content) and overall handling time. The average amount of harvested propolis (18 g per colony and year) was lower compared to literature data (i.e. 50 g per colony and year). Some grids can not be recommended because of non-inert materials. The best results were achieved by using a flat, horizontal plastic grid with 2 mm slits on top (n=16, ANOVA; p<0.005). The best season for collection differs from year to year; the harvesting tools can remain on top of the hive for the whole season. The quality of the harvested propolis can be improved by sorting out big parts of beeswax. Concerning the balsam content, the quality is mainly influenced by the location and depends on plant sources in the surrounding. By the use of thin-layer chromatography we discriminated two types of German propolis (Popolus nigra and another one of uncertain origin). The project was funded by WALA Heilmittel GmbH, Germany.

33

5.6 Project „Healthy Colonies“ – How may an improved consultation of beekeepers look like? - Projekt „Gesunde Bienenvölker“ – Wie kann eine verbesserte Beratung von Imkern aussehen?

Gefion Brunnemann-Stubbe, V. Poker, R. Büchler (Kirchhain)

Obwohl es wirksame Behandlungsmittel und -konzepte gegen Varroose gibt, sterben immer wieder viele Bienenvölker an ihren Folgen. Ziel des Projektes ist es herauszufinden, warum die Konzepte nicht umgesetzt werden bzw. wie die Imker bei der Umsetzung der Konzepte unterstützt werden können. Am Projekt nehmen 150 Imker mit über 1000 Völkern aus sieben Imkervereinen in Hessen teil. Wichtigster Projektbestandteil sind Praxistermine an Bienenständen von Projektimkern, bei denen die einzelnen Elemente eines integrierten Varroabehandlungskonzeptes gezeigt und von den Imkern ausprobiert werden. Diese Praxistermine stoßen bei den Imkern auf gute Resonanz (Teilnehmerzahlen 40-90 %). Es hat sich gezeigt, dass die empfohlenen Behandlungsmethoden grundsätzlich praxistauglich sind, aber von vielen Imkern nicht in ihre eigene Imkerpraxis umgesetzt werden. Grund dafür sind zum einen Unkenntnis wichtiger Zusammenhänge und Defizite bei der Beurteilung des Gesundheitszustandes der Völker, zum anderen die große Methodenvielfalt, die zu erheblichen Anwendungs-Unsicherheiten und -Fehlern führt. Die Auswertung von Bienenproben von 10 % der Völker zur Kontrolle ihres Gesundheitszustandes hat bestätigt, dass die Winterverluste der Projektimker eng an den Befall mit Varroa destructor gekoppelt sind. Für die Beratung ist es wichtig, die Informationen unmittelbar mit der Praxis am Bienenstand zu verbinden. Ein Schwerpunkt sollte dabei auf der Beurteilung der Völker und ihres Gesundheitszustands liegen. Um dies in der Fläche zu erreichen, wurde ein Teil der ehrenamtlichen Imkerberater in Hessen als Multiplikatoren in der Durchführung von Praxisveranstaltungen geschult, sie haben im Sommer 2012 über 300 Teilnehmer in den Vereinen erreicht. Der Einsatz von Multiplikatoren in den Vereinen soll auch im Hinblick auf die besondere Bedeutung der Ausbildung von Anfängern ausgeweitet werden.

6. Genetik & Zucht 6.1 Spatial and temporal expression patterns of serotonin receptor subtypes in the honeybee, Apis mellifera - Räumliche und zeitliche Expressionsmuster von Serotonin-Rezeptor-Subtypen der Honigbiene, Apis mellifera

Daniel RolkeS, M. Thamm, W. Blenau (Oberursel, Potsdam)

The biogenic amine serotonin (5-HT) controls and modulates a great variety of physiological and behavioral processes by interacting with various 5-HT receptor

34

subtypes. In the honeybee, Apis mellifera, four 5-HT receptor subtypes have been characterized: Am5-HT1A, Am5-HT2α, Am5-HT2β, and Am5-HT7. Interestingly, Am5-HT2 receptors are expressed both as a full length transcript and as a shortened splice variant, as it is known for certain dopamine receptors in Caenorhabditis elegans and humans. To provide a basis for further investigations and to develop testable hypotheses, e.g., on the physiological and behavioral functions of 5-HT receptor subtypes, the tissue specific expression patterns of both Am5-HT2 receptors were investigated in the honeybee using quantitative real-time PCR. In the nervous system and exocrine glands, the expression of the full-length Am5-HT

2α transcript was higher than that of the shortened splice variant,

whereas the opposite holds true for Am5-HT2β

. In the brain, the expression of both Am5-

HT2 receptors is considerably lower than that of Am5-HT1 and Am5-HT7. Eusocial insect societies are characterized by division of labor. The age-dependent division of labor in honeybees is correlated with increasing serotonin levels in the brain and is also associated with the development of circadian activity rhythms. We compared the 5-HT receptor expression in the brain between different age groups. Moreover, we investigated daily oscillations of 5-HT receptor mRNAs.

6.2 Colony performance, behavior and disease susceptibility of two genotypes from Apis mellifera macedonica population in the Republic of Macedonia - Leistung, Verhalten und Krankheitsanfälligkeit zwei verschiedener Apis mellifera macedonica Genotypen in der Republik Mazedonien

Aleksandar UzunovS, R. Büchler (Skopje, Kirchhain)

Apis mellifera macedonica is described as native subspecies on the territory of South-Eastern Europe, including the whole territory of Republic of Macedonia. Beside numerous morphological and molecular studies there is very limited information published so far regarding its typical traits and variations within the population. For that reason, two local genotypes were tested for 17 traits concerning colony performance, behavior and susceptibility to honey bee diseases by internationally recognized methods. Twenty colonies with identical number of queens from both genotypes were established on each of two testing apiaries close to Skopje in the Republic of Macedonia. Twenty-four censuses were performed in 21 day intervals during the active beekeeping season (March-October) from 2009 to 2012. Using Generalized Linear Model we statistically analyzed the effect of main factors (year, season, month, location and genotype) and the effects of covariables, such as pollen, worker and drone brood and bee population in the colony. We identified the existence of multimodal colony developmental trajectories during the year and a disparity of the developmental peaks among the genotypes. Additionally, moderate defensive and pronounced swarming behavior was indentified in both genotypes. Due the used control measures the infestation with Varroa destructor constantly remained below the economic threshold level. However, we found that the colonies from both genotypes were sensitive to strong winter conditions with longer flightless periods and to Nosema spp. infection.

35

6.3 Adaptive Evolution of RNAi Genes in Bumblebees - Adaptive Evolution von RNAi Genen bei Hummeln

H. Michael G. Lattorff, S. Helbing (Physiol. Mol. Ökol., Halle)

Social insects are prone to parasites and pathogens. High density of closely related individuals enhances pathogen transmission. Adaptations and counter adaptations between hosts and parasites left their signatures in the genome, especially on antiviral RNAi genes indicated by the high rates of adaptive evolution. In order to quantify the impact of host-parasite conflict effects on the evolution of RNAi genes in social insects, six genes were partially sequenced and compared across different species of the genus Bombus. Additionally, we test for the impact of sociality on molecular evolution by a direct comparison of social species and their respective socially parasitic cuckoo bumblebees. Hence, we could show that RNAi genes exhibit an elevated rate of adaptive evolution compared to non-immune genes, assuming a co-evolutionary interplay between RNAi genes and viruses, as the latter evade hosts defense mechanisms by production of suppressor-proteins that interfere with the RNAi- pathway. Furthermore, RNAi genes exhibit a great variance in their rates of adaptive evolution closely linked to their pathway-specific position, since proteins that directly interact with viral components evolved most rapidly. We compared the evolutionary rates of RNAi genes between cuckoo bumblebees (non-social) and their respective host lineages to infer the impact of sociality on the molecular evolution, as both, host and social parasite, experience similar selective pressures due to the shared environment. Here, we show that RNAi genes evolved significantly faster in social species due to their larger population sizes and higher mutation rates.

6.4 Using DNA pools for genotyping colonies of the honeybee Apis mellifera with microsatellite DNA - Nutzung von DNA-pools zur Genotypisierung von Honigbienenkolonien, Apis mellifera, mit Microsatelliten DNA.

Nadège Forfert, E. A. Schlüns, O. R. Paniti-Teleky, E. M. Furdui, D. S. Dezmirean, R. F. A. Moritz (Cluj-Napoca, Osnabrück, Halle, Mol. Ökol.)

Genotyping large sample sets with microsatellite DNA loci is both time consuming and cost intensive. We here present a new technique to screen pooled samples of workers to assess the colony genetic structure of honeybees (Apis mellifera) and use this data for population genetic studies. We verified the technique by comparing the actual allele frequencies derived from individual genotypes with estimates obtained from DNA pools of the same individuals. We show that this method can be used to determine allele frequencies with considerable precision, detecting rare alleles down to a threshold of 89%. The technique can be used for colony “genotypes” in population genetic studies but

36

is also useful for colony level analyses in combination with individual genotyping to reduce the work load for detecting the presence of foreign individuals in colonies.

37

Posterpräsentationen

1. Honig- & Wildbienenökologie P1 Effects of mass flowering oilseed rape on resource use and foraging of honey bees- Einfluss der Massentracht Raps auf die Ressourcennutzung und das Sammelverhalten von Honigbienen

Anna Maria MolitorS, N. Danner, S. Härtel, I. Steffan-Dewenter (Würzburg, ZOO III)

Die Honigbiene (Apis mellifera) ist ein wichtiger Bestäuber vieler Wild- und Kulturpflanzen. Analysen der als Futterquelle dienenden Pflanzenarten wurden in der Vergangenheit schon häufig durchgeführt. Die genaue räumliche Verteilung der Nahrungsquellen in der Landschaft durch Entschlüsselung der Bienentänze wurde bisher kaum untersucht. Winterraps (Brassica napus) wird auf großen Flächen angebaut, spielt als Massentracht eine wichtige Rolle für die Ernährung der Honigbienen und benötigt im konventionellen Anbau intensive Pflanzenschutzmaßnahmen. Es fehlen jedoch Studien, die systematisch die Nutzung von Rapspollen durch Honigbienenvölker, und damit die Exposition gegenüber potentiell kontaminierten Rapspollen erfassen. In einem landschaftsökologischen Ansatz wurde untersucht, welchen Einfluss Raps auf die Ressourcennutzung und das Sammelverhalten von Honigbienenvölkern hat. An 16 verschiedenen Standorten im Umkreis von Würzburg wurde jeweils ein Beobachtungsstock etabliert. Die Landschaften in 2 km Radius um die Standorte bildeten einen Gradienten von niedriger zu hoher Rapsanbaufläche. Vor und während der Rapsblüte wurden 1029 Pollentänze beobachtet, aufgenommen und decodiert. Die Daten zeigen einen signifikanten Zusammenhang zwischen dem Rapsanteil der Landschaften und der Anzahl der Pollensammelflüge auf Raps. Der Raps wurde häufig als Pollenressource verwendet und je mehr Raps vorhanden war, desto häufiger wurde er angeflogen. Es besteht folglich die Gefahr, dass Honigbienen bei intensivem Rapsanbau vermehrt Agrarchemikalien ausgesetzt sind, die im Pollen vorhanden sind. Des Weiteren können im Flugradius vorkommende Wildpflanzen während der Rapsblüte in ihrer Bestäubung vernachlässigt werden.

P2 Monitoring agricultural ecosystems by using wild bees as environmental indicators - Monitoring von Agrarökosystem mit Wildbienen als Umwelt-Indikatoren

Matthias Schindler, O. Diestelhorst, S. Härtel, C. Saure, A. Schanowski, H.R. Schwenninger (Bonn; Düsseldorf; Würzburg, ZOO III; Berlin; Stuttgart)

Wild bees are abundant in agricultural ecosystems and contribute significantly to the pollination of fruits and crops. The specialisation of many wild bees on particular nesting sites and food resources makes them sensitive to changing habitat conditions. For this

38

reason wild bees are considered as important indicators for environmental impact assessments. However, guidelines for wild bee monitoring are currently lacking. Here we present a highly standardized monitoring approach on wild bees which combines active transect walks with temporarily located pan traps (bowls). The combination of these field ecological methods provides high sample coverage and reveals direct data on plant-pollinator interactions. Long term exposed pan traps are very effective at trapping bees and would negatively influence local bee populations. The suggested approach is applicable to diverse monitoring goals in an agricultural context e.g. the impact of land use changes, pesticide use, climate change, invasive bee diseases as well as monitoring potential effects of commercialized genetically modified crops. Initial monitoring should be documented through a three-year field study. Subsequent studies should be repeated every five years to record the status quo and the changes in biodiversity of wild bee communities. Long-term monitoring will provide data that allow distinguishing between annual population fluctuations of wild bee species and effects attributed to environmental change. An assessment using biotic indicators such as wild bees requires crucial ecological and taxonomic qualifications. Therefore we encourage the establishment of courses to qualify collaborators for our suggested monitoring schemes with wild bees. The monitoring approach was worked out as part of the VDI guideline 4332.

P3 Wild bee habitats in arable landscapes of Brandenburg – as web-map on the participative information platform on the protection and promotion of wild and honey bees - Lebensraumqualität Brandenburger Agrarlandschaften für Wildbienen – eine Internet-Karte der partizipativen Informationsplattform zum Schutz und zur Förderung von Wild- und Honigbienen

Burghard Golla, S. Kühne, R. Lessing, B. Lichtenberg-Kraag, C. Saure, F. Schönburg (Kleinmachnow, Hohen Neuendorf, Ludwigsfelde, Berlin, Potsdam)

Unter dem Projekttitel „gEoBEE“ wird eine partizipativ angelegte Diskussions- und Informationsplattform zum Schutz und zur Förderung von Wild- und Honigbienen erarbeitet. Dieses Internetportal schafft die informationstechnischen Vorrausetzungen und fachlichen Inhalte, um den Dialog und Informationsaustausch zwischen Imkerei und Naturschutz und Landwirtschaft zu unterstützen. Verortung und räumliche Darstellung von Informationen, die keinen primären Ortsbezug besitzen und deren Überlagerung mit neuen oder bislang nicht zugänglichen Informationen sind ein Schwerpunkt des Projekts. In zahlreichen Internet-basierten Kartenanwendungen werden die Informationen und Datenbanken verschiedenster Quellen (behördlich, institutionell, privat) kombiniert, neue Erkenntnisse daraus erzeugt und diese der Öffentlichkeit mit Focus auf die Zielgruppen Imkerei, Naturschutz und Landwirtschaft zugänglich gemacht. Die Informationsdienste stehen nach Abschluss des Projekts kostenfrei über das neue Internetportal bereit. Ergebnisse liegen aus der Analyse von Lebensraumpotentialen für Wildbienen vor. Kleinstrukturen (KS) in den Agrarlandschaften stellen wichtige Nahrungs-, Nist- und

39

Rückzugshabitate dar. Räumliche Daten zur Landschaftsstruktur Brandenburgs (ATKIS Basis-DLM) wurden GIS-basiert analysiert. Die Auswertungen erfolgten für regelmäßige 1km² Kacheln. Es wurden nur Kacheln mit einem Ackerflächenanteil > 0.1 ha berücksichtigt. Innerhalb einer Kachel ist der Untersuchungsraum auf die Umgebung von 500m um die Ackerflächen begrenzt (vgl. Enzian & Gutsche (2004), Nachrichtenbl.Deut.Pflanzenschutzd., 56 (12) 299-308). Es wurden 22 529 Kacheln analysiert. Der mittlere KS-Anteil beträgt 15.3 % (Std Dev 16, 8). Der Median liegt bei 9,9 % (25% Quartil bei 5,8, 75% Quartil bei 17,4). Das Poster zeigt die räumliche Verteilung. Weitere Standortmerkmale (Bodeneigenschaften, Exposition, Inklination) sind noch zu berücksichtigen.

P4 Unnoticed victims - Losses of pollinators caused by road traffic - Unbeachtete Tote - Verluste von Bestäubern durch Straßenverkehr

Monika WeberS, J. Weber, S. Härtel, D. Mahsberg (Würzburg, Zoo III)

Jedes Jahr verlieren nicht nur viele Wirbeltiere, sondern auch unzählige Wirbellose ihr Leben im Straßenverkehr, wobei Insekten besonders betroffen sind. Über das Ausmaß dieser Verluste und über mögliche Konsequenzen auf Ökosystemleistungen ist bisher jedoch fast nichts bekannt. In einer achtjährigen Studie wurden die Insektenverluste an einer Kreis- und einer Landesstraße nahe Kiel/Schleswig-Holstein quantifiziert; hierfür wurden jeweils beide Straßenränder der 3 km langen Untersuchungsstrecke wöchentlich nach toten Insekten abgesammelt. Den Totfunden wurden die entsprechenden GPS-Koordinaten zugeordnet, um die Verteilung der Insektenleichen mit Landschaftsparametern vergleichen zu können. Es wurden insgesamt 12 382 tote Insekten gesammelt, von denen bisher 4 045 (2007, 2009 und 2010) so genau wie möglich bestimmt sind. Die meisten dieser Opfer sind mit 65 % Hautflügler (Hymenoptera), darunter 89 % Bienen (Apidae). Unter diesen fielen Honigbienen (Apis mellifera) zu 21 %, vor allem aber Sandbienen (Andrena spp., 34 %) und Hummeln (Bombus spp., 42 %) dem Straßenverkehr zum Opfer, wobei der Anteil an Geschlechtstieren bei Hummeln ca. 30 % betrug. Besonders hohe Insektenverluste traten in Flugkorridoren auf. Flugaktivität und Unfallwahrscheinlichkeit hingen auch mit der Wetterlage zusammen. So schwankte der Anteil toter Honigbienen in der Nachbarschaft blühender Rapsfelder zwischen 9 und 40 %. Der hohe Anteil toter Bienen unter den Verkehrsopfern legt negative Konsequenzen für die Bestäubung von Wild- und Nutzpflanzen nahe. Weiterhin zeigt die Studie, welchen Einfluss u.a. das Vegetationsmuster an Straßen auf gesetzlich geschützte Wildbienen-Populationen haben kann, woraus Konsequenzen für die Verkehrsplanung gezogen werden sollten.

40

P5 Water foraging and water balance in honeybees (Apis mellifera) - Wassersammelaktivität und Wasserhaushalt der Honigbiene (Apis mellifera)

Mareike WeißS, G. Liebig, P. Aumeier, W.H. Kirchner (Bochum, Hohenheim)

Water foraging has been studied in honeybees (Apis mellifera) mainly in the context of colony thermoregulation. Relatively little is known about the water balance of honeybee colonies and about water foraging throughout the year. In the light of recent reports on the contamination of guttation water of seed-dressed crops we studied the water foraging activity of 10 honeybee colonies from April to October 2012. Returning foragers were captured in front of the beehives. Bees were collected several times a day. In addition, weather conditions, foraging activity and the nectar availability were recorded. About 2500 successful nectar and water foragers (returning with a total weight of more than 100 mg) were forced to regurgitate a sample of the collected food, which was analyzed with a digital refractometer. Bees were classified as water foragers when the crop sugar concentration was below 3%. We found that in total about 18% of these foragers collected-water. They contributed on average about 32% to the total water intake (in six month 84,9 l). However, water foraging activity is highly variable. It is affected by time of day, temperature and nectar availability. Water foraging and colony nectar intake are negatively correlated. Water is generally collected when the nectar intake rate is not sufficient to cover the need of water, which happens either when the colonies feed on stored honey or when water is required for cooling purposes.

P6 Which flowering field stripes benefit wild bees? A comparison of seed-mixtures and management - Welche Blühstreifen fördern Wildbienen? Ansaatmischungen und Pflege im Vergleich

Bärbel Pachinger, B. Prochazka (Wien)

Um dem Verlust der Biodiversität in den Europäischen Agrarlandschaften entgegen zu wirken, wurden in verschiedenen Ländern Agrar-Umweltprogramme ins Leben gerufen. In Österreich wird so die Anlage von „Nützlings- und Blühstreifen“ gefördert. Die Optimierung dieser Streifen in Hinblick auf eine Förderung der Wildbienenfauna ist dabei ein wichtiges Thema. Ziel dieser Studie ist daher, unterschiedliche Ansaat-Mischungen und verschiedene Pflegemaßnahmen der Blühstreifen zu vergleichen. In einem Ansaatversuch wurde auf dreijährigen Flächen (1) eine in der landwirtschaftlich übliche Ansaatmischung (10 Pflanzenarten wie zum Beispiel Klee-Arten, Phacelia, Sonnenblume) mit (2) einer Blühmischung (87 autochthonen Wildkrautarten) verglichen (n=8). In einem Bearbeitungsversuch wurden auf fünfjährigen Flächen die Pflegevarianten (1) Grubbern, (2) Grubbern und Nachsaat und (3) keine Bearbeitung gegenübergestellt (n=4). Die Untersuchungstransekte liegen auf einem Betrieb mit biologischer Landwirtschaft in Rutzendorf in Niederösterreich, im Osten von Österreich. Die

41

Wildbienen wurden an sieben Tagen zwischen Mitte April und Ende September 2012 entlang von Transekten jeweils 20 Minuten erfasst. Der Vergleich der Ansaatmischungen zeigte einen signifikanten Unterschied (Kruskal Wallis Test, p=0,0264) der Individuenhäufigkeiten zu Gunsten der Blühmischung. Der Vergleich der Artenzahlen zeigte keinen signifikanten Unterschied, mit p= 0,0689 jedoch ebenfalls deutliche Tendenzen zu mehr Arten auf den Flächen der Blühmischung. Der Bearbeitungsversuch zeigte keine signifikanten Unterschiede. Der gewünschte Effekt der Maßnahme Grubbern mit dem Ziel, die Sukzession neu zu starten und durch zusätzliche annuelle Pflanzen die Phytodiversität zu erhöhen und dadurch wieder vermehrt Bienen auf die Fläche zu bringen, war gering. Pflügen von alten Blühstreifen wird als neue Versuchsvariable vorgeschlagen.

P7 Developement of honey bee colonies during the pollination employment of sweet cherries under foil - Entwicklung von Honigbienenvölkern beim Einsatz zur Bestäubung von Süsskirschen unter Folie

Andreé Hamm, D. Papendick, J. Lorenz (Bonn)

Beim Anbau von Süsskirschen unter Folien, ist eine gute Bestäubung eine der Grundvoraussetzungen, um die gewünschten Erträge in entsprechender Qualität zu erzielen. Aufgrund der Tatsache, dass Honigbienen ungern unter Schutzfolien fliegen, kann es insbesondere im Zentrum der Anlage, zu Ertragseinbußen kommen. Für den Einsatz von Honigbienen zur Bestäubung bedeutet das, dass die Völker über die gesamte Obstanlage verteilt aufgestellt werden müssen. Die aus einem solchen Aufstellungsmuster resultierenden Auswirkungen auf die Volksentwicklung wurden in der vorliegenden Arbeit untersucht. Darüber hinaus wurden der entstehende imkerliche Mehraufwand und die zusätzlichen Kosten eruiert. Hierzu wurden insgesamt 19 Bienenvölker eingesetzt, von denen 16 Völker flächendeckend in der Anlage (3ha) und drei weitere als Kontrolle auf dem Heimatstand aufgestellt wurden. Die Ergebnisse der abschließenden Populationsschätzung (Bienen/ verdeckelte Brut) zum Zeitpunkt des Auswanderns zeigen zunächst, dass sich die 16 Völker in der Obstanlage (x=16.895 Einheiten, n=16) im Mittel nur geringfügig schlechter entwickelten als die Kontrollvölker (x=17.438 Einheiten, n=3). Bei genauerer Betrachtung wird jedoch deutlich, dass es bei den Völkern, die im Zentrum der Anlage unter der Schutzfolie eingesetzt wurden (n=6), zu hohen Bienenverlusten von bis zu 42% kam, während bei den Völkern im Randbereich gleichzeitig ein „Bienenzuwachs“ von über 300% zu verzeichnen war. Es kam daher offensichtlich innerhalb der Anlage zum starken Verflug von Bienen der Völker im Zentrum der Anlage hin zu denen, die im Randbereich standen. In der Folge entstand so ein erheblich höherer Arbeitsaufwand, da Völker mit z.T. 6 Zargen nicht mehr zu transportieren waren. Auch der geringere Honigertrag aus der Frühtrachtschleuderung bei den Versuchsvölkern (-43 %), stellt für den Imker einen wirtschaftlichen Verlust dar, den es zu kompensieren gilt.

42

P8 Which Bee Species (Hymenoptera, Apiformes) visit Flowers of the Wild Service Tree (Sorbus torminalis)? - Welche Bienenarten (Hymenoptera, Apiformes) besuchen die Blüten der Elsbeere (Sorbus torminalis)?

Jula WerresS, D. Wittmann (Bonn)

The Wild Service Tree (Sorbus torminalis) is a very rare fleshy fruited tree, belonging to the Rosaceae family. Today there are only some scattered and mostly isolated populations left which are endangered by the decreasing diversity of their genetic material. Pollination is the only way to conserve the genetic material and to produce seeds for forestry purposes. Bees are the most effective pollinators for S. torminalis. In 2011 and 2012 during the flowering stage for one week at the beginning of May, flower visitors were trapped with an insect net and air eclector-traps in the blossoming canopy. Additionally, the visitor’s behaviour was recorded. The field experiments were carried out in a forest stand in a nature reserve close to Bonn and a seed orchard between Cologne and Bonn. A good quarter of all flower visiting insects were bees (Hymenoptera, Apiformes). In total, 25 bee species were recorded. The represented families in descending order of majority were Andrenidae (62 %), Apidae (35 %), Halictidae (2 %) and Colletidae (1 %). Four bee species were dominant (Engelmann, 1978): Andrena haemorrhoa, Apis mellifera, Andrena nitida and Bombus terrestris. The white flowering aspect of S. torminalis is loosely arranged in umbels with 34 (sd +14) flowers in average. The nectar is easy available for a wide range of insects because the yellow coloured flower tube is rather short, with the floral nectaries on its bottom. Accordingly, nearly all of the visiting bees had a short proboscis. The flower traits for a special pollination syndrome are ambiguous: The floral scent is both sweet and putrid. Beetles should be attracted by the easy available anthers, the fruity putrid compound of the scent and the open bowl shaped petals. This putrid scent is also attractive for a wide range of flies. Bees maybe attracted by the sweet compound of the scent, which is reminiscent of honey and also by the relatively large quantity of pollen. The detected bees were mainly collecting pollen more than drinking nectar.

43

2. Pflanzenschutz & Bestäubung P9 New method for determination of smallest volumes of nectar from small flowers - Neue Methode zur Bestimmung von Kleinstmengen von Nektar aus kleinen Blüten

Abdulrahim AlkassabS, D.C. Albach, D. Brückner (Bremen)

Die häufigste Methode zur Bestimmung von Nektarvolumen ist die Benutzung von Mikrokapillaren. Aber diese Methode funktioniert nicht für die Bestimmung des Nektarvolumens in kleinen Blüten wie Sinapis arvensis, da die Nektarvolumen in solchen Blüten sehr gering (≤ 1 μL) sind. Daher wird eine geeignete Methode für die Extraktion und Messung aus kleinen Blüten getestet, wobei wie folgt verfahren wird: Die Blütenstände werden mit Papiertüten am Tag vor dem Experiment eingepackt, um den Besuch von Bestäubern zu verhindern. Am nächsten Tag werden die geöffneten Blüten aus den Papiertüten gesammelt und einzelne Blüten werden in 1,5 ml Mikrozentrifugenröhrchen platziert und ins Labor gebracht. Dort werden die Staubblätter abgeschnitten, um zu verhindern, dass sich beim Zentrifugieren der Pollen mit dem Nektar mischt. Jede Blüte wird dann in ein 1 ml eingewogenes Mikrozentrifugenröhrchen platziert, dann 7 min. mit einer Geschwindigkeit von 4000 gn zentrifugiert. Nach der Zentrifugation werden die Blüten aus den Röhrchen entnommen und die Röhrchen erneut für 2min. mit einer Geschwindigkeit von 4000 gn zentrifugiert, damit alle Nektartröpfchen sich zu einem einzigen Tropfen zusammenfügen. Das Gewicht der Röhrchen wird nach der Zentrifugation mit einer Feinwaage (0,00001 g) bestimmt. Das Nektarvolumen wird anhand der Differenz zwischen dem Gewicht der Röhrchen vor und nach der Zentrifugation berechnet. Der Nektar wird aus dem Röhrchen mit einer feinen Spritze (Hamilton 75 N; 5μL) aufgenommen und dann die Zuckerkonzentration des Nektars durch ein Handrefraktometer (45-80%, Bellingham und Stanley, Tunbridge Wells,

UK) bestimmt. P10 Global evaluation of bee pollinators to agricultural crops - Weltweite Bewertung von Bienen-Bestäubern für Kulturpflanzen

Virginie Boreux, A.-M. Klein (Lüneburg)

Pollination by bees is increasingly recognised as a central ecosystem service provided to a large number of crops worldwide and contributing to the increase and stability of production. The common honey bee, Apis mellifera, is considered a privileged pollinator of crops, among other reasons due to the large size of its colonies and its long time domestication. Other bees and bumble bees have also been shown to substantially contribute to the pollination of a variety of crops, such as cucurbits or solanaceae. We are interested in the relative importance of pollinators, taking into account crop species, variety and location of the production. For this purpose we are building a database, compiling and summarising information from pollination studies published in

44

the past 100 years, on over 60 major crops grown across the world. Information gathered includes pollinators and their impact on fruit and seed production. Outline of our project and methodology will be presented in this poster.

P11 The cobblers stick to their lasts: Pollinators prefer native over introduced plant species in a multi-species experiment - Schuster, bleib bei Deinen Leisten: Bestäuber ziehen in einem Mehrarten-Experiment einheimische den eingeführten Pflanzenarten vor

T. Chrobock, Pius WinigerS, M. Fischer, M. van Kleunen (Bern, Konstanz)

Flowering plants, in particular angiosperms, and insects are two relevant taxa that prevail the biotic world on Earth’s land surface. The majority of angiosperms largely rely on animals, rather than on abiotic agents such as wind or water. Here we investigated pollinator visitation in artificial (i.e., gardens) and semi-natural habitats to better understand possible effects of pollinator visitation on spread of invasive angiosperm species from human-assisted occurrence in gardens to more natural habitats. Using 17 plant species from five families, we artificially placed one native, non-invasive, and invasive plant species in artificial and semi-natural habitats (i.e., three plants per habitat). In general, pollinator visitation was significant higher for native compared to the alien plant species (mean±SE: pollinator individuals: 8.70±0.79 on native and 4.12±0.36 on alien species; pollinator morpho-species: 3.69±0.30 on native and 2.11±0.14 on alien species; pollinator groups: 2.64±0.18 on native and 1.88±0.12 on alien species), but did not differ between introduced invasive and introduced non-invasive plant species (mean±SE; pollinator individuals: 3.93±0.50 on invasive and 4.26±0.51 on non-invasive species; pollinator morpho-species: 2.25±0.19 on invasive and 2.00±0.20 on non-invasive species; pollinator groups: 2.07±0.17 on invasive and 1.73±0.16 on non-invasive species). Moreover, pollinator visitation was on average higher in semi-natural than in artificial garden habitats (mean±SE; pollinator individuals: 7.87±0.71 in semi-natural and 4.15±0.37 in urbanized sites; pollinator morpho-species: 3.51±0.26 in semi-natural and 2.04±0.16 in urbanized sites; pollinator groups: 2.74±0.17 in semi-natural and 1.70±0.11 in urbanized sites). These data suggest that once introduced species have escaped from gardens into more natural habitats, pollinator limitation will not be a major barrier to establishment and invasion.

45

P12 BICOPOLL: Targeted Precision Biocontrol and Enhanced Pollination - BICOPOLL: Zielgerichtete und präzise biologische Kontrolle und verstärkte Bestäubung

H. Hokkanen, A.-L. Aase, D. Bevik, O. Boecking, A. Cokl, L. De Meyer, Y. Dupont, C. Eken, R. Karise, B. Maccagnani, Ingeborg Menzler-Hokkanen, M. Mänd, G. Smagghe, N. Söderlund, S. Tuncer, E. Veromann, P. Witzgall (Helsinki und andere)

BICOPOLL and BICOPOLL-NET bring together 12 research units from 10 different European countries and regions into a concerted effort to develop, and to bring into practice, improved methods of biological control and pollination services, using strawberry as the case study. Berry and fruit production suffers heavily from the lack of effective disease and pest management tools, and from inadequate insect pollination at times. BICOPOLL partners use bees to (i) precision deliver biological control agents to the flowers of the target crops to provide control of problem diseases (or pests), and to (ii) improve the pollination of horticultural crops. BICOPOLL is providing a pan-European case study on protecting strawberry from its most important disease, the grey mould. In addition we are improving the efficiency of entomovectoring via innovative research on bee management, manipulation of bee behavior, components of the cropping system, and on the plant-pathogen-vector-antagonist –system, and investigating the possibilities of expanding the concept into other berry and fruit growing systems. The entomovector -approach represents the only significant breakthrough in sight for improving plant protection in organic cropping systems, particularly in high-value crops. It also can bring significant benefits to conventional growers. BICOPOLL investigates, exploits, and supports the natural ecological functions of biocontrol and pollination, and enhances these via innovative management. The entomovector technology contributes to improved resource use and efficiency in production, and enhances local biodiversity unlike most other plant protection systems. The main target groups of the BICOPOLL project are organic and conventional strawberry growers, other berry and fruit growers, as well as beekeepers and their organizations. The projects will cover three growing seasons, from 2012 till 2014.

P13 Effect of Dropleg spray application in oilseed rape on pollen and nectar contamination - Effekte einer optimierten Applikationstechnik (Dropleg) auf die Pollen- und Nektarkontamination im Winterraps

Klaus Wallner, C. Maus, M. Tritschler, R. Friessleben, R.-B. Toews (Hohenheim, Monheim)

Oilseed rape is one of the most important agricultural crops in Germany (cropping area > 1.5 mio ha), and likewise of key importance in beekeeping as early-season bee forage. To prevent losses of yield, oilseed rape has to be treated with different pesticides during blooming season. The application of pesticides into the blossoms has led to residue findings in honey which caused concerns by beekeepers. We present a concept to

46

optimize pesticide application technology, towards minimization of exposure of bees to pesticide residues in treated blossoms. The under-leaf application technology is a modified system (Dropleg) that has been used in vegetable crops for several years. In semi-field and field trials in 2011 and 2012 it was tested in how far under-leaf spray with the Dropleg system in flowering oilseed rape can reduce pesticide residues in nectar and pollen collected by exposed bee colonies in comparison to conventional application technology. Pollen loads and stored nectar of experimental bee colonies were sampled at different points of time after application and analyzed for pesticide residues. As model substances, a systemic fungicide and a non-systemic insecticide were applied, in 2012 additionally a systemic insecticide. First results from 2011 suggest that Dropleg application can significantly reduce pesticide exposure of bee colonies. The project is conducted in the scope of the FitBee Project supported by German BMELV and will be continued until 2014.

3. Physiologie & Verhalten P14 The protein and carbohydrate share in honey bee trophallaxis - Der Protein und Kohlenhydrat-Anteil bei der Trophallaxis

Anika LöweS, K. Crailsheim (Graz)

In honey bee colonies nurses are able to discriminate between different larvae (queen, workers and drones) and between differently aged worker larvae. Nurses feed each of them with distinct composed diets (Planta (1888), Z. Physiol. Chem. 12: 327-354; Babendreier et al. (2004), Apidologie 35: 31-83). With this background we investigated if the differentiation in feeding is continued among worker bees after emerging as adults. In lab assays, the trophallactic interactions between a donor (7-9 days of age) and two types of recipient bees (one-day old, n=31 and 7-9 days old nurse bees, n=26) were observed. For each experiment a donor was caged with one recipient in an arena. Each donor bee was fed with 15µl of 3 M glucose solution before it was introduced into the arena to evoke offering behavior. The recipients only showed frequent begging behavior when they were forced to regurgitate and starved for 3 h (one-day old bees) and 1h (nurse bees). A single trial lasted maximum 15 min or until the onset of a trophallactic interaction. The protein levels of the honey stomach contents of both the donor and recipient were measured to determine the composition of the transferred liquid. Other parameters to evaluate modifications during trophallaxis were the time until onset and the duration of the trophallaxis. The preliminary results indicate that there are no significant differences in the onset and duration of trophallaxis between one-day old and nurse bees (p>0.05, Mann Whitney). Recipient nurse bees received a median amount of 8.06 mg of sugar solution, which is higher than for one-day old bees (4.16 mg; p<0.05Mann Whitney). The median amount of 8.03 µg of transferred protein per nurse bee is significantly higher in contrast to 1.86 µg a one-day old bee obtained (p<0.05,

47

Mann Whitney). The results suggest that the recipient nurses have produced secretions from the hypopharyngeal glands and have stored them in the honey stomach.

P15 Insights into the comb cell building behaviour of honeybees - Einblicke in das Wabenzellbauverhalten der Honigbienen

Daniel BauerS, K. Bienefeld (Hohen Neuendorf)

The nests of European honeybees (Apis mellifera) are organised into wax combs that contain many cells with a hexagonal structure. Many previous studies have been made of comb building behaviour to understand how bees produce this geometrical structure but it still remains a mystery. Direct construction of hexagons by bees was suggested previously, while a recent hypothesis postulated the self-organised construction of hexagonal comb cell arrays; We monitored comb building behaviour by using infrared and thermographic video observations to provide insights into the cell building technique of honeybees. Bees used their antennae, mandibles and legs in a regular sequence to manipulate the wax, while some bees supported their work by actively warming the wax. Temperatures were well below 40°C, i.e., the temperature at which wax is assumed to exist in the liquid equilibrium that is essential for self-organised building. We conclude that bees have a concept of their cell geometry.

P16 Is the CaMKII a possible mediator for the molecular mechanism of learning and memory in the honeybee? - Spielt die CaMKII in der Honigbiene eine Rolle bei den molekularen Mechanismen von Lernen und Gedächtnis?

Christina SchollS, W. Rössler (Würzburg, ZOO II)

Honeybees are excellent models to study learning and memory processes. They are well known for their complex behaviours and their abilities to learn complex tasks. The neuronal and molecular bases underlying long-term memory in behaviour is key to understanding higher brain function and social organization. One protein known to play an important role in memory processes in mammals is the calcium-calmodulin dependent protein kinase II (CaMKII). This protein is an abundant synaptic protein that has been shown to be an important mediator of learning and memory. In the bee the mushroom bodies (MB) are known as important sensory integration and association centers involved in learning and memory. The CaMKII gene and protein were found at high concentrations in the MBs. Here we ask whether CaMKII is involved in the process of long-term memory (LTM) formation in the bee. To study the role of CaMKII in the formation of LTM, bees are trained using a conditioning paradigm, the proboscis extension response (PER). To investigate the potential role of CaMKII we started to disrupt the function of CaMKII using RNA interference (RNAi). siRNA

48

against CaMKII was used to induce RNAi and to create a knock down phenotype in the MBs. Furthermore, we use pharmalogical inhibition of CaMKII as a parallel approach. The siRNAs (@CaMKII, @GFP) and the inhibitors (KN93, KN92: ineffective analog) were injected in the brain through the ocellar tract to specifically reach the MBs, which was visually confirmed by fluorescently tagged siRNA. Quantitative immunoblots showed a successful downregulation of the protein 6 hours after the injection of the siRNA. Based on these results PER training is performed 6h after the injection of the siRNA to test the influences of the CaMKII on memory acquisition and retention at 1h, 24h and 48h after the learning trials. In the long run the experiments are aimed to understand the potential role of CaMKII as a molecular link in the formation of long-term memory in the honeybee.

P17 Search for early indicators of damage to bee colonies - Suche nach Frühindikatoren für Schäden an Bienenvölkern

Haike Ruhnke, K. Milchreit, J. Wegener, G. Kamp, M. Barth, K. Bienefeld (Hohen Neuendorf, Mainz, Machern-Gerichshain)

Bee colonies are affected by a series of factors, e. g. food supply, weather conditions, presence of pathogens, parasites, pesticides, and disturbances. Some of the factors are known to have detrimental effects on bee colonies. However, it is not easy to detect sublethal and/or long-time effects at colony level at an early stage. In order to identify early indicators for reduced colony vitality, 63 bee colonies were either exposed to pesticides (imidacloprid, fenoxycarb) or left untreated as controls. Samples of hive bees, pollen foragers and larval food were taken shortly after the exposure (sampling date 1) and before winterizing (sampling date 2). From these samples, around 40 potential indicators of colony vitality were measured, covering nutritional state, brood rearing, worker fertility and body reserves. For statistical evaluation, relationships of the measured parameters with the number of bees per colony in the following spring were analysed. Besides of correlations with colony size at sampling time, the proboscis extension reflex (PER) of foragers treated with imidacloprid was correlated with overwintering strength (sampling date 2, Spearman’s rang correlation, p < 0.05). Further, the size of the largest oocyte of queenless-held hive bees (sampling date 1) seemed to be negatively associated with the number of bees per colony in the following spring (Spearman’s rang correlation, p < 0.05). Parameters measured in larval food and in hive bees were also correlated with the overwintering strength. However, we cannot be more specific because of potential property rights. Additional experiments are presently being performed to verify parameters as early indicators of colony-level damage.

49

P18 Voltage-clamp recordings of honeybee olfactory projection neurons in intact brain preparations - Spannungsklemmenmessungen von olfaktorischen Projektionsneuronen in intakten Gehirnen der Honigbiene

Jan KropfS, W. Rössler (Zoo II, Würzburg)

Olfaction is a crucial sense for honeybees (Apis mellifera), as they rely on olfactory cues to find nectar sources and to communicate within the hive. Odor information is transmitted into the first central relay station, the antennal lobe (AL), via olfactory sensory neurons (OSNs), which synapse on local interneurons and projection (output) neurons (PNs). In honeybees, two sets of uniglomerular PNs project to the MBs via two parallel, anatomically distinct tracts, the medial and the lateral antennal lobe protocerebral tract (m- and l-APT). This dual olfactory pathway represents a special feature in Hymenoptera. Odor response patterns of the m-APT are more odor specific and sparser than the l-APT response patterns (see Poster M. Brill et al.). This might be due to either differences in the synaptic connectivity of m- and l-APT neurons within the AL, different intrinsic properties of PNs from the two tracts, or a combination of both. In the present study we set out to investigate whether m- and l-APT PNs differ in their intrinsic properties, e.g. their ion channel composition. We conducted in situ whole cell voltage clamp recordings from PNs in intact brain preparations. To be able to to distinguish between cell bodies of PNs and those of local interneurons before recording, we injected dextran-coupled tetramethyl-rhodamine (MicrorubyTM) into the mushroom bodies to let the dye be transported retrogradely along PN neurites. Using a fluorescence microscope we were able to detect and selectively record from stained cell bodies of PNs. Using selective labelling of the m- and l-APT as well as anatomical identification of distinct groups of cell bodies, selective recordings from either l- or m-APT PNs are possible. In the first experiments, typical ionic currents, i.e. fast sodium currents, A-type potassium currents and sustained potassium currents could be observed. In a next step we aim to identify and characterize potassium and calcium currents in the two subsets of PNs.

P19 Are the effects of fenoxycarb on honey bee brood queen- or nurse bee-mediated? - Werden die Effekte von Fenoxycarb auf die Bienenbrut durch die Königin oder die Ammenbienen verursacht?

Kathrin MilchreitS, K. Bienefeld (Hohen Neuendorf)

It is known that insect growth regulators frequently lead to queen loss. Here, we tested the hypothesis that queens of fenoxycarb-exposed colonies produce defective eggs, which could explain their elimination by workers. Moreover, we investigated whether brood in such colonies is damaged due to exposure of queens, or through the intermediary of nurse bees, or both. Additionally, we tested the effect of the solvent, dimethyl sulfoxide (DMSO), on bee brood. Small bee colonies were fed with (a) sucrose solution, (b) sucrose-DMSO-fenoxycarb solution, and (c) sucrose-DMSO solution,

50

respectively. Egg samples from all colonies were reared in an incubator for measuring the hatching rate. New and empty combs were added to the colonies for conducting a reciprocal egg transfer experiment with the following pairs: (i) sucrose-fed colonies and other sucrose-fed colonies (5 colonies); (ii) sucrose-DMSO-fed colonies and other sucrose-DMSO-fed colonies (6 colonies); (iii) sucrose-fed colonies and sucrose-DMSO-fenoxycarb-fed colonies (8 colonies). Development of brood was recorded every fourth day until hatching. We found no differences in hatching rate among the treatments (Kruskal-Wallis test; p > 0.05). The transfer experiment showed that brood from treated colonies, reared in untreated colonies survived similarly well as brood from untreated colonies, reared in other untreated colonies (Mann-Whitney-U test; p > 0.05). Survival of brood from untreated colonies, reared in treated colonies was significantly decreased, as was that of brood from DMSO treated colonies (Mann-Whitney-U; p < 0.05). Our results point out that the effect of fenoxycarb/DMSO to bee brood is mainly nurse bee-mediated. Exposure of the queen has small or no effects on larval hatching and brood development. DMSO, previously seen as a non-toxic solvent, appears to have an effect on honey bee brood rearing.

P20 Effects of the insecticide thiacloprid on the flight behavior of honeybees measured by Radio Frequency Identification (RFID) - Effekte des Insektizides Thiacloprid auf das Flugverhalten von Honigbienen, gemessen mithilfe von Radiofrequenz-Identifikation (RFID)

Lena FaustS, J. Hahn, B. Grünewald (Oberursel)

Honeybees get into contact with insecticides while collecting pollen and nectar. The neonicotinoid thiacloprid is supposed to be relative low toxic to bees, though sublethal effects on the behavior are not studied very well yet. We examine the influences of sublethal doses of thiacloprid on the flight behavior of honeybees under field conditions by using the RFID microchip technique. For our studies about the effects of chronic uptake of thiacloprid by larvae, we simulated the consumption of thiacloprid via nectar by feeding colonies with sugar syrup containing 5000 ppb thiacloprid in the hive, respectively with pure sugar syrup for control, under flight tents. After pupation, the tents were removed and the bees were free to forage for pollen and nectar. After eclosion, bees were labeled with RFID microchips to record them leaving or returning to the hive. To estimate the date of death for each marked bee, the day of the last registration was noted. Bees that were fed with sugar syrup containing 5000 ppb thiacloprid as larvae started significantly later for their first flight, and they lived significantly longer than bees fed with pure sugar syrup. Secondly we investigated whether and how an acute uptake of 250 ng thiacloprid per bee influences the homing flight behavior of honeybees.

51

Adult bees were caught upon leaving the hive, chipped with RFID microchips and brought to four release sites at distances between 200 and 900 meters from the hive. The bees were fed with 10 µl of diluted honey either with thiacloprid added or without and then were allowed to imbibe pure diluted honey ad libitum. Immediately they were released and the duration they required to fly back to the hive was evaluated. There were no significant differences between the duration of homing flight of the groups, but higher bee losses in the thiacloprid-fed group. Sublethal doses of the neonicotinoid thiacloprid appear to delay the behavioral development of honeybees and may interfere with their navigational capacities.

P21 Effects of neonicotinoid insecticides on motor and neuronal activity in the honeybee - Einflüsse von Neonikotinoiden auf die motorische und die neuronale Aktivität der Honigbiene

Martina TriltschS, J. Fischer, K. Kabat vel Job, B. Grünewald (Oberursel)

Neonicotinoid insecticides act as agonists of the insect nicotinic acetylcholine receptor. We tested the effects of the neonicotinoids, clothianidin, thiacloprid, and imidacloprid, on the motor activity and the nervous system of bees. We show that the substances induce different effects. In a first approach we monitored the locomotor activity of adult honeybee workers in a small walking glass arena (diameter: 13,6 cm). The walking traces were recorded for a period of 3 min before and after the bees were fed individually with 10 µL of sucrose solution supplemented with clothianidin (0.4µM) or thiacloprid (400µM). Clothianidin-treated bees increased the walking speed as compared to control animals (10 µL sucrose solution). By contrast, the walking speed of thiacloprid-treated bees decreased. To analyze the effects of neonicotinoids on muscle activity we extracellularly recorded spike activity of the proboscis muscle M17 before and during application of 1 µL clothianidin, thiacloprid, or imidacloprid (1µM) into the open head capsule. Application of 1 µL phosphate-buffered saline was used as a control. Muscle spikes and proboscis extension were elicited by touching the antennae and the proboscis with a toothpick soaked in sucrose solution. Clothianidin increased the number of muscle spikes significantly as compared to the control group and in some animals even led to tonic spiking in the absence of stimulation. By contrast, imidacloprid as well as thiacloprid reduced the spike activity during the whole recording period (1h) with a significant difference of imidacloprid to the control 30 minutes after application. Our results indicate distinct effects of the various insecticides on honeybee locomotor activity. We are currently investigating the effects of insecticides on the nervous system of the honeybee assuming that the observed effect is induced via modulating cholinergic synaptic transmission in the central nervous system.

52

P22 Odor identity coding reveals parallel processing in the honeybee olfactory system - Duft-Kodierung im Gehirn der Honigbiene zeigt Parallelverarbeitung im olfaktorischen System

Martin F. Brill, A. Meyer, M.P. Nawrot, W. Rössler (Würzburg, ZOO II; Berlin)

Animals face complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems. It is characterized as extraction of different parameters along parallel sensory information streams but its role in olfaction remained unclear. Honeybees possess an elaborate olfactory system with unique neuronal architecture, a dual olfactory pathway comprising a medial and lateral projection-neuron (PN) output tract (m-, l-APT) connecting the olfactory lobes with higher order brain centers. This peculiarity is exclusively found in Hymenoptera (e.g. bees, ants, wasps). We used this specific adaptation as a model system to address the importance of parallel processing in olfaction. We employed a novel experimental technique for simultaneous multi-unit recordings from both antennal-lobe output tracts (Brill et al. (2013), J Neurosci 33:2443-2456). This revealed detailed response profile characteristics of high numbers of PNs to a variety of floral, pheromonal and biologically relevant odors. PNs of both tracts responded to all tested odors but with different characteristics indicating parallel processing. L-APT PNs were activated by multiple odors (broad response profiles), whereas m-APT PNs responded with sparse activity pattern and high odor-specificity. Comparison of response latencies of PNs within and across both output streams revealed odor-dependent latency patterns that likely support a dual tract temporal code, possibly promoting coincidence coding at the level of the mushroom body input. We conclude that parallel processing via the honeybee’s dual olfactory pathway enhances performance for sophisticated odor perception as required under complex natural stimulus conditions of a social insect. Supported by DFG SPP 1392 (RO 1177/5-1) and BMBF (01GQ0941).

P23 Development of a siRNA based method to experimentally manipulate the molecular clock of honey bees - Etablierung einer siRNA-basierten Methode zur experimentellen Manipulation der Inneren Uhr von Apis mellifera

Katharina BeerS, I. Steffan-Dewenter, S. Härtel (Würzburg, ZOO III)

The daily and seasonal variation of floral resources is a significant challenge for foraging honey bees. As an evolutionary adaptation honey bees show well-developed time memories based on a circadian clock to synchronize their foraging activity. In order to study the effect of two central clock genes, period (per), and crypotochrome-m (cry-m) on time memory and foraging success of honey bees’ two molecular methods were tested. First, we tested if a persisting gene knock-down effect can be obtained by adding per-

53

siRNA to the diet of laboratory reared bee larvae. After emergence the circadian rhythmicity of the treated bee incubated under light–dark illumination and eventually under constant dark regime was measured by a locomotor activity monitor. A lack of circadian rhythm patterns in the bioassay under constant dark illumination would point to a successful gene knock-down in the bee. It turned out that there was no significant difference in the rhythmicity between bees fed with per-siRNA, gfp-siRNA or a water fed control group. As a consequence, we secondly followed an additional gene knock-down approach by feeding siRNA to freshly hatched adult bees. Here again siRNA treated bees and the controls showed no distinct differences in activity rhythms. The gene expression of the target gene of both approaches is currently analyzed with real-time PCR using SYBR Green and specific primers. The result will clarify whether there was a knock-down effect at all in the bees, or if the application of per-siRNA just induces only a short lasting gene knock-down. This could explain the preservation of circadian rhythms in the knock-down phenotype observed in our bioassay. The presented work is part of the recently started collaborative research center: Insect timing, mechanisms, plasticity and interactions (SFB 1047).

P24 Side-specific olfactory learning in the honeybee: localization und dynamics of memory retention - Seitenspezifisches Duftlernen bei der Honigbiene: Lokalisation und Dynamik des Gedächtnisabrufes

Sandra ZimmermannS, V. Schützmann, B. Grünewald (Oberursel)

Honeybees can learn odors in a side-specific way. For this the proboscis extension reflex is trained unilaterally to an odor applied to only one antenna. The formed side-specific memory is initially restricted to the trained side, but is then transferred to the non-trained side about 3h after training. To investigate the dynamics and the localization of side-specific memory retention and the interactions between the brain hemispheres, we separated the olfactory input of the bee’s space by a plastic sheet. We tested the interaction between transferred information and new acquisition by applying differential learning during phase 1 and reversal learning or differential conditioning with 2 novel odors on the non-trained side during phase 2 (3 h after phase 1). We then tested retention of all odors of either group on both sides. We hypothesize that if the initial memory (formed during phase 1) stays lateralized reversal or differential learning should not differ on the non-trained side. If the learned content of phase 1 is transferred to the non-trained side reversal learning should be hindered. Both groups (differential and reversal) learned to discriminate between the two odors during phase 2 equally well indicating a lateralized initial memory. However, training to those odors that yielded high conditioned response rates during phase 1 impaired reversal learning on the non-trained side. This indicates an interhemispheric memory transfer after learning of salient odors. In addition reversal learning during phase 2 on the non-trained side increased the response rate to the initially unrewarded odor on the trained side. The memory formed after phase 1 can be retrieved 3-6h after training on the non-trained side. By contrast retention of the 2. phase memory can be retrieved already after 30-60 min.

54

Taken together our results suggest stabile side-specific memory with interhemispheric information transfer depending on the training and the salience of the conditioned odor.

P25 Aspects of synaptic plasticity in the mushroom-body calyx during adult behavioral maturation in the honeybee - Aspekte synaptischer Plastizität im Pilzkörper-Calyx während der adult Reifung von Honigbienen Arbeiterinnen

Thomas S. Münz, C. Groh, A. Maisonnasse, K. Grübel, Y. Le Conte, W. Rössler (Würzburg, ZOO II, Avignon)

Honeybee workers express a pronounced age-dependent polyethism and a behavioral repertoire ranging from various indoor duties (nurse bees) to foraging outside the hive (foragers). This transition is accompanied by tremendous changes in the sensory environment that sensory systems and higher brain centers have to cope with. Previous studies showed that foraging and age are associated with volume changes in the mushroom bodies (MBs), brain structures involved in multi modal sensory processing, learning and memory. We used age- and task-controlled bees in normal colonies to investigate structural plasticity of synaptic complexes (microglomeruli, MG) in the MB calyx during adult behavioral maturation. Pre- and postsynaptic compartments were visualized using markers for synaptic proteins and cytoskeletal elements and analyzed by quantitative 3D confocal imaging. Changes in density and number of MG revealed presynaptic pruning together with increased postsynaptic dendritic branching as the major cause underlying volume changes. Synaptic reorganization started prior to onset of foraging, ~1 week after adult eclosion. We hypothesize that this correlates with the onset of first orientation flights. To further investigate the flexible regulation of division of labor in a honeybee colony, we studied its modulation via a chemical communication system, the primer pheromone Ethyloleate (EO). EO is found at high concentrations only on foragers and was shown to delay the onset of foraging in nurse bees. We applied additional EO to triple cohort colonies to artificially delay onset of foraging in focal bees and analyzed structural synaptic plasticity in the MB calyx. EO effects on colony behavior were not as robust as expected, and we found no direct correlation between EO treatment and synaptic maturation. We conclude that the primer pheromone EO does not directly affect synaptic maturation and rather acts in concert with other factors influencing the onset of foraging.

55

P26 The path to ASSISI|bf: How honeybees and machines can make collective decisions - Der Weg zu ASSISI|bf: Wie Honigbienen und Maschinen kollektive Entscheidungen treffen können

M. Szopek, S. Hahshold, R. Thenius, M. Bodi, T. Schmickl, Karl Crailsheim (Graz)

When single young honeybees are introduced to a complex thermal gradient with one optimum place that has 36 °C, most of the bees are unable to locate themselves at their preferred temperature of 36 °C. In contrast to that, groups of young honeybees in a similar thermal environment are able to aggregate at the optimum preferentially. Thus, we conclude that groups of bees solve the self-localisation problem collectively and are also able to make collective decisions: In an thermal environment with one optimum at 36 °C and one sub-optimum at 32 °C they collectively choose the optimum place and do not get stuck in the sub-optimum during gradient exploration. It is also possible to manipulate the bees' decision by introducing caged bees in the sub-optimum: This so called „social gradient“ allows us to interfere with the decision making of the group. In the recently started EU project ASSISI|bf we will further investigate which stimuli are relevant to initiate such changes in the collective behaviour of bees. We plan to research different types of stimuli (e.g., odour and vibration) and to measure the behavioural responses exhibited by the bees. We will focus on behavioural responses of single bees when confronted to a certain stimulus (escaping, aggression, attraction, ...), and we will study the behaviour of groups of bees after introducing a given stimulus. Based on our findings we plan to develop specific robotic devices, which are able to interact with the bees in an autonomous way. The main goal of the project ASSISI|bf is to enable the communication between animals and robots, creating a mixed bio-hybrid self-organising society of animals and machines.

P27 Temperature preferendum of young, single honeybees in a temperature organ - Temperaturpreferendum einzelner, junger Honigbienen in der Temperaturorgel

S. Hahshold, R. Ploder, T. Schmickl, Karl Crailsheim (Graz)

It is a known fact that young honeybees have a temperature preferendum near 36°C. This was investigated by Heran (1951) in a temperature organ (steep gradient, 1dimensional). Groups of young honeybees were introduced in a temperature gradient and the temperature preferendum was determined. Surprisingly he never investigated single, young honeybees in this device, but always groups of honeybees. In recent experiments we could experimentally show that there is a strong social component in the thermotactic behavior of young honeybees. We also found that only a few young, single honeybees are able to find their temperature preferendum in a flat, 2dimensional gradient and a round arena. We wanted to know whether single, young honeybees are able to find the temperature preferendum in a steep and 1dimensional gradient (temperature organ).

56

We conducted experiments according to Heran (1951), but we investigated single, young honeybees. The bees were introduced in the temperature organ and every minute their position was recorded. We calculated the local temperature of the bee´s position. Experiments lasted 30 minutes and a total number of 98 bees were tested. The median temperature where the bees were located was 34,5° C and the mean temperature was 33,1 °C. 50% of the bees were located between 29,8 and 37,25 ° C. Our results show that single, young honeybees perform another thermotactic behavior than groups of young honeybees. We could experimentally show that the mean temperature preferendum of single, young honeybees is much lower than reported in literature for groups of young honeybees.

4. Bienenpathologie P28 Genetic and phenotypic variance of Melissococcus plutonius isolates in Switzerland. An approach to fight European foulbrood? - Genetische und phänotypische Unterschiede von Melissococcus plutonius Isolaten in der Schweiz. Ein neuer Ansatzpunkt zur Bekämpfung der Europäischen Faulbrut?

Daniela SteinerS, L. Gauthier, V. Dietemann, M. Chapuisat, J.D. Charrière (Liebefeld)

European Foulbrood (EFB) is a severe disease of honey bee (Apis mellifera) brood caused by the bacterium Melissococcus plutonius. In Switzerland, the number of EFB cases has increased considerably during the last decade. Knowledge on the pathomechanisms is lacking and control measures applied in Switzerland, which entail destroying symptomatic colonies, are not satisfying and cost intensive. The recently initiated project presented in this poster aims at better understanding the epidemiology of this bacterium, as a basis for finding solutions to better control EFB. Our goals are: i) developing breeding protocols towards the selection of EFB tolerant honey bees; ii) identifying variations in the phenotype of the pathogen; iii) genotyping M. plutonius isolates. Our first results show phenotypic differences between various swiss M. plutonius isolates, which are potential key factors for their virulence level.

P29 Investigations on the horizontal transmission of Wolbachia in bees - Untersuchungen zur horizontalen Übertragung von Wolbachia bei Bienen

Denise AumerS, M. Gerth, C. Bleidorn (Halle, Mol. Ökol.)

Wolbachia pipientis, ein gramnegatives, intrazellulär lebendes Bakterium, wurde bisher bei 20-75% aller Arthropoda nachgewiesen. Die Übertragung kann dabei sowohl horizontal als auch vertikal erfolgen. Der vertikale Transfer innerhalb einer Art, findet über die Eizelle von der Mutter an die Nachkommen statt. Die Mechanismen der horizontalen Übertragung zwischen den Arten, sind bei den meisten Tiergruppen jedoch

57

unbekannt. In dieser Studie wurden daher die Wege der horizontalen Übertragung von W. pipientis bei Bienen untersucht. Es wurde die Hypothese aufgestellt, dass W. pipientis an der Blüte, an der sich viele verschiedene Bienenarten zum Pollen- und Nektarsammeln treffen, über den Pollen horizontal übertragen wird. Um diese Hypothese zu testen, wurde ein Infektionsversuch ausgearbeitet, in dessen Fokus die Rote Mauerbiene Osmia bicornis stand, da bei dieser bisher noch keine Infektion mit W. pipientis nachgewiesen wurde. Die Pollenkuchen der Brutzellen dieser Art wurden in einem frühen Entwicklungsstadium bewusst mit W. pipientis Zellen versehen. Die auf dem mit dem Bakterium angereicherten Nahrungsbrei heranwachsenden Nachkommen wurden in regelmäßigen Abständen mittels diverser etablierter Nachweismethoden (PCRs, Färbungen) auf W. pipientis untersucht. In wenigstens einem Fall war die Infektion erfolgreich und es konnte Wolbachia pipientis mittels einer Antikörperfärbung gegen ein Oberflächenprotein des Endosymbiontens zweifelsfrei nachgewiesen werden. Außerdem kann W. pipientis ca. eine Woche außerhalb des Wirts überleben. Die Möglichkeit einer horizontalen Übertragung von Wolbachia pipientis über den Pollen zwischen Bienen, konnte durch diesen Versuch belegt werden und ist möglicherweise für alle blütenbesuchenden Insekten relevant.

P30 A rapid and cost efficient assay to detect multiple honeybee pathogens - Ein kosteneffizienter Schnelltest zum Nachweis multipler Honigbienenpathogene

Eckart StolleS, R.F.A. Moritz (Halle, Mol. Ökol.)

The decline in densities of honeybee colonies is a major issue for pollination services in natural ecosystems and agricultural landscapes in numerous regions in the world. As there have been serious colony losses due to honeybee pathogens, the detection and monitoring of such pathogens is crucial. Apart from some invertebrate parasites, such as different mites, wax moth or small hive beetle, there are numerous microbial organisms exploiting the honeybee as a host. Although several molecular assays were published to detect those bacteria, fungi or viruses, a comprehensive, reliable and efficient test is still needed for rapid large scale screens. We developed a rapid and cost-efficient system to detect numerous pathogens in single reactions. The PCR based test has been optimized for high efficiency regarding costs, time and workload. We aim at detecting 11 viruses in 2-4 multiplex reactions, of which 1, containing some of the most common viruses, is established. Using our approach, an extracted RNA sample can be screened and analyzed within 3 hours. Furthermore we investigated the potential to obtain semi-quantitative data. In addition to viruses, we also work on an assay to detect several bacterial and fungal pathogens in a similar fashion.

58

P31 Do not fight against Varroa - get rid of it! - Warum Varroa bekämpfen, wenn Bienenhaltung ohne Varroa möglich ist?

Heikki M.T. Hokkanen, I. Menzler-Hokkanen (Helsinki)

Poster zu Vortrag 4.3

P32 Eight-year cohort study of Nosema ssp. in Germany - Kohortenstudie über acht Jahre zur Epidemiologie von Nosema spp. in Deutschland

Kati Hedtke, Elke Genersch (Hohen Neuendorf)

Nosema ceranae and Nosema apis are two fungal pathogens belonging to the phylum Microsporidia and infecting the European honey bee, Apis mellifera. Recent studies suggested that N. ceranae is more virulent than N. apis at the individual insect level and at the colony level. Severe colony losses could be attributed to N. ceranae infections and an unusual form of nosemosis caused by this pathogen. In the present study, data from an eight year cohort study on the prevalence of Nosema spp. in Germany involving about 220 honey bee colonies and a total of 3701 samples collected from these colonies each spring and autumn and analyzed via species-specific PCR-RFLP are described. Since 2010, we additionally collected samples in July to also analyze the prevalence of Nosema spp. infections in summer. Statistical analysis of the data did not reveal any relation between colony mortality and detectable levels of infection with N. ceranae or N. apis. A possible explanation for these findings could be the observed marked decrease of spore germination already after short exposure to low temperatures (+4 °C) only for N. ceranae. Reduced or inhibited N. ceranae spore germination at low temperatures should hamper the infectivity and spread of this pathogen in climatic regions characterized by a rather cold winter season.

P33 Different strategies for manipulation of Paenibacillus larvae - Unterschiedliche Strategien zur Manipulation von Paenibacillus larvae

Lena PoppingaS, A. Fünfhaus, E. Garcia-Gonzalez, G. Hertlein, K. Hedtke, E. Genersch (Hohen Neuendorf)

P. larvae is a grampositive, spore forming bacterium causing the globally occuring epizootic American Foulbrood affecting the brood of honeybee larvae. The four different P. larvae genotypes (ERIC I - ERIC IV) clearly differ in terms of virulence. In order to understand genotype specific pathogenesis on molecular level, different genetic tools for manipulation of P. larvae were successfully established. For this purpose appropriate electroporation protocols suitable for transformation of different expression plasmids in P. larvae ERIC I and ERIC II were established. Firstly, the uptake of the green fluorescence

59

protein (GFP) expression plasmid pAD43-25 was verified by detecting heterologous expression of GFP in P. larvae during all stages of growth. Also, GFP expression could be verified after sporulation and germination by fluorescence microscopy. The ability to transform P. larvae by electroporation was the prerequisite to further apply a knockout system in P. larvae. With the help of a group II intron located on an appropriate plasmid (pTT), we were able to specifically disrupt genes by intron insertion. For this purpose the intron cassette located on the plasmid was manipulated by site directed mutagenesis at specific sites to retarget the intron into the gene of interest. Several putative P. larvae virulence factors were knocked out by this method. Knockout mutants could be further investigated in infection assays to draw conclusions of functional roles of these virulence factors. Furthermore, plasmid pAD43-25 was manipulated to constitutively express the P. larvae ERIC II specific S-layer protein SplA in the naturally SplA lacking genotype P. larvae ERIC I. The heterologous expression could be detected by specific labelling of SplA by a C-terminal Histidin-tag and subsequent visualisation by a specific AlexaFluor dye.

P34 Molecular differentiation of Nosema apis and Nosema ceranae based on species-specific sequence differences in a protein coding gene - Molekularbiologische Differenzierung von Nosema apis und Nosema ceranae anhand von speziesspezifischen Sequenzunterschieden eines proteinkodierenden Gens

Sebastian GisderS, E. Genersch (Hohen Neuendorf)

Nosema apis and Nosema ceranae are obligate intracellular pathogens of the European honey bee Apis mellifera. Infection with N. apis may lead to dysentery (nosemosis) and a slightly shorter live span of individual bees but colony losses are rarely described. In contrast, N. ceranae has been identified as causative agent of colony losses in some geographical regions leading to the assumption that N. ceranae is more virulent than N. apis. A prerequisite for epidemiology and analysis of virulence of N. ceranae and N. apis is the correct identification of and differentiation between these two microsporidian species. In the recent past molecular differentiation methods, based on 16S (SSU) rRNA gene sequence differences of both species had been established. However, several independent studies revealed that most of the widely used, simple PCR-based methods showed a tendency to produce misleading results because the allegedly species-specific primers pairs lacked species-specificity. A possible explanation for this phenomenon is the known sequence variability of the multi-copy 16S rRNA genes. To solve this problem we developed a duplex-PCR protocol based on species-specific sequence differences in the highly conserved DNA-dependent RNA polymerase (RNAP) -gene of N. apis and N. ceranae. We evaluated our novel duplex-RNAP-PCR protocol by analyzing a total of 102 Nosema spp.-positive bee samples and comparing these results with the results obtained via the very robust PCR-RFLP analysis, originally developed for differentiation between both species, and two recently published, simple 16S rRNA gene based-PCR protocols relying on allegedly species-specific primers pairs. Our results revealed that both, PCR-

60

RFLP and the duplex-RNAP-PCR indeed provided highly specific and reliable molecular tools for the correct differentiation of Nosema spp. while the two simple 16S rRNA gene-based PCR protocols resulted in misleading results and an overrepresentation of N. ceranae.

P35 Host dependent triggering of the reproduction of Varroa destructor - Aktivierung und Unterbrechung der Reproduktion von Varroa destructor durch Wirtsfaktoren (Apis mellifera)

Eva FreyS, R. Odemer, T. Blum, P. Rosenkranz (Hohenheim)

The reproductive cycle of the parasitic mite Varroa destructor is closely linked to the development of the honey bee host larvae. For reproduction, the female mite enters the bee brood cell shortly before cell sealing. Our previous experiments demonstrated that certain developmental stages of the host larva are capable of either activating or interrupting the reproductive cycle of V. destructor females. Using a within colony bioassay we showed that larvae are only able to stimulate the mite’s oogenesis within 18 hours (worker) and 36 hours (drone), respectively, after cell capping. Therewith we could exactly define the short time frame where the bee larvae provide the signals for a successful activation of V. destructor reproduction. In an additional approach we could furthermore confirm that an already initiated oogenesis can be interrupted if the mite is transferred to an older larval stage. We assume that both, stage specific semiochemicals and nutritional signals of the host larvae are involved in the triggering of the reproductive cycle of V. destructor females. Among the semiochemicals some fatty acid esters of the larval cuticle have already been proven to be involved in host parasite interactions and, therefore, represent candidate compounds. We analyzed the quantitative pattern of 5 methyl and 3 ethyl esters on the cuticle from those larval stages (workers and drones) that have either an activating or inhibiting effect on the mite’s reproduction. Based on our results, certain ethyl esters could be involved in the first activation process for V. destructor oogenesis. For the further prove of a possible causative correlation, an in vitro system allowing the artificial application of volatiles and food to reproducing mites is urgently needed.

P36 Sperm capacitation and possible disturbance of sperm transfer in Varroa destructor - Spermienreifung und mögliche Störung der Spermienübertragung bei Varroa destructor

Hannah SchmittS, B. Ziegelmann, P. Rosenkranz (Hohenheim)

During the mating of Varroa destructor, males insert a spermatophore into the copulatory pores of the female. In the female genital tract the transferred spermatozoa pass through a capacitation process. In order to analyze this capacitation process we first established an in vitro system, where Varroa destructor females perform their adult molt and were allowed to mate with male mites under controlled conditions. Here we present

61

microscopic pictures providing an overview over the female´s genital tract and the capacitation process of sperm cells. Through anatomic dissections we were able to document the transformation from spherical sperm cells to the terminal pole shape stage. The complete process of capacitation takes about 5 days. The reproductive capacity of female mites at different time periods after mating – and therefore different times for the capacitation process - was tested through introduction of dated females into honey bee brood cells. The results indicate that the fecundity of the introduced mites is higher after a capacitation time of 8 days compared to only 2 days. In further experiments we could confirm that the infertility of brood mites is neither correlated with the presence or number of spermatozoa in the spermatheca. Finally we tested whether an application of synthetic sex pheromone (Ziegelmann et al., 2013; Apidologie) could disturb the successful transfer of the spermatophore. Our preliminary experiments did not result in a decreased insemination success; however, this test system could be used for further studies with regard to a biological control method based on sex pheromones.

P37 Number of differential hemocytes/µl in honeybee larvae of immune-stimulated queens - Hämozytenprofil in Bienenlarven nach Immunstimulation der Königin

Javier Hernández-LópezS, W. Schuehly, U. Riessberger-Gallé, K. Crailsheim (Graz)

Studies in invertebrates have revealed extraordinary features of the immune responses triggered upon infection. Induced immune responses, in some cases accompanied of specificity, and trans-generational immune priming (TI) are considered now to be common among invertebrates. This latter phenomenon refers to a parental immune experience that is transmitted to progeny and has a positive impact on offspring´s survival to infection. Recently, the occurrence of TI has been demonstrated in honeybees by our research group. Besides the evaluation of survival rates of queen’s offspring upon pathogen exposure, we were interested in the effects of immune priming on the population of hemocytes. Hemocytes are the immune cells of the innate immune system of invertebrates and prohemocytes are the non-immune competent precursor cells of all hemocyte populations (differential hemocytes). Honeybee queens were primed by injecting heat-killed bacteria of Paenibacillus larvae (Pl), a spore-forming bacterium causing American Foulbrood. Subsequently, offspring of stimulated queens and controls (injection with Ringer) were artificially reared and at day six, hemolymph was extracted and used to perform hemocyte counts. Total hemocyte counts (prohemocytes and differential hemocytes) and differential hemocyte counts were performed. No statistically significant differences were found for total hemocyte counts between control and larvae of Pl-challenged queens (Mann-Whitney U-Test p = 0.735). Notably, we found statistically significant differences between the differential hemocyte counts for the two treatment groups (Mann-Whitney U-Test p = 0.003). The percentage of differential hemocytes of total counts was 0.98 % in control larvae compared to 3.22 % in larvae of Pl-challenged queens. We propose that maternal immune experience triggers differentiation of prohemocytes to prepare offspring for a prevailing pathogen.

62

P38 Chronic bee paralysis virus infections of honey bee queens - Infektion von Bienenköniginnen mit Chronischem Bienenparalysevirus

E. Amiri, Marina Meixner, R. Büchler, P. Kryger (Kirchhain, Slagelse)

Queens are in general the healthiest member of the colony, often amongst the last surviving individuals in dying hives. We tested the infection of queens with CBPV under a variety of conditions. In experiment 1, we subjected a set of one year old queens to a laboratory infection trial. The queens were divided into 4 groups, all kept in metal cages with 30 healthy workers each, at 28°C and 65% r.H. Sugar syrup, pollen paste and water were provided ad. lib. They received the following treatment: E: a small area on the thorax was shaved and 4 µl of virus solution was applied (5*10^8 viral copies); C1: shaved and 4µl of H2O applied; C2: shaved only; C3: nothing. Symptoms of CBPV (shaking, uncoordinated movements) and mortality of queens and workers were recorded daily. Dead queens and queens alive by day 14 were collected and frozen. Viral titers of CBPV were determined using qRTPCR. In group E, the first symptoms were observed on d6 after infection (50% of queens), and by d7, all queens were symptomatic. Mortality of queens started on d6, and by d14 all queens had died. In group C1 60% of queens developed symptoms and 50% died; in C2 and C3 few queens developed symptoms, but the pattern was less clear. In experiment 2, three groups of virgins were infected. (1) Queens infected with shaving and application of virus appeared healthy after 6 days and had low viral titres. (2) Queens were infected by placing them together with symptomatic workers in the incubator. All of these developed symptoms after 6 days and were highly positive for CBPV. (3) Queens were placed in cages together with symptomatic workers, but the cages were kept in nucs with healthy workers. Most of these queens remained healthy for 9 days, and had very low levels of CBPV. In our experiments, one year old queens appeared more susceptible to CBPV infection than virgins. CBPV infection may have spread in the incubator among the one year old queens. Virgins with access to healthy workers through the queen cage became infected with CBPV to a lesser extent.

P39 Mite Away Quick StripsTM, a new and easy way to keep Varroa in check? - Mite Away Quick StripsTM, eine neue und einfache Art der Varroa-Kontrolle?

Patricia BeinertS, P. Aumeier, W.H. Kirchner (Bochum)

Effective control of Varroa destructor is a prerequisite for sustainably healthy and productive Apis mellifera colonies. One crucial device of successful treatment strategies is Formic acid (FA), the only varroacide capable of killing both phoretic and reproductive mites simultaneously. However, the narrow therapeutic range and the extreme variable efficacy of FA, depending on ambient microclimatic and within-hive conditions, require a

63

carefully tuned mode of application. Mite Away Quick StripsTM (MAQSTM), with its new FA delivery method in gel formulation might open up a new approach in this problem area. In field trials we tested MAQSTM, in comparison to two established FA-applicators emitting 60% or 85% FA. 75 honey bee colonies, randomly distributed amongst 11 experimental groups, were treated once or twice in autumn 2012. Effectiveness of FA was assessed by one control treatment with oxalic acid in broodless colonies. Moreover, to evaluate the compatibility of different treatments, we assessed bee mortality (by use of death traps in front of the bee hives), overall colony development (estimated according to the Liebefeld method), and loss of queens, respectively. In comparison to currently available methods, the MAQSTM, containing 46.7% FA, performed a consistent and high efficacy in singular as well as in double treatments (82±19% and 92±5% mite mortality, respectively). Thus, it attained an effect as high as known from the most reliable common dispensers using 85% FA (Nassenheider professional 88±21%; Liebig-Dispenser 72±19%) and exceeded any 60%-FA-treatment (Nass prof 64±7%; Liebig-Dispenser 36±28%). As we could neither detect any differences in worker bee or queen mortality, nor in population development between the different types of FA-application, the use of MAQSTM could be a promising future tool to control Varroa destructor. Besides its good efficiency, this form of application is much easier compared to the common handling of liquid FA.

P40 Elimination of Varroa destructor after passage from foraging bees through the Varroa-Gate - Elimination von Varroa destructor nach Passage von Flugbienen durch das Varroa-Gate

Sebastian WernigS(Oberursel)

Beim Varroa-Gate handelt es sich um einen gelöcherten Kunststoff-Akarizidträger, welcher im Flugloch installiert wird. Bienen können nur durch die Löcher im Gate das Flugloch passieren. Durch die Passage der Biene mit einer phoretische Milbe sollte diese abgetötet werden. Hier wird der Zusammenhang zwischen der Mortalität von Varroa destructor mit der Flugaktivität des Bienenvolkes untersucht. Wir haben die Flugaktivität mit Videokameras vor dem Flugloch des Bienenvolkes aufgezeichnet und über die Software Fiji die Anzahl der Flüge bestimmt. Zeitgleich wurde täglich die Anzahl der toten Milben im Bienenvolk protokolliert. Die Anzahl der toten Milben an Tagen mit hoher Flugaktivität war deutlich abzugrenzen von Tagen ohne Flugaktivität. Somit konnte eine Korrelation zwischen Flugaktivität und der täglichen – vom Varroa-Gate verursachten- Milbenfall gezeigt werden.

64

P41 Immune answer of summer and winter bees under naturally DWV infection - Immunabwehr Immunantwort von Sommer- und Winterbienen unter natürlicher Infektion mit DWV

Nadja SteinmannS, B. Dainat, P. Neumann (Bern)

Sommer- und Winterbienen unterscheiden sich deutlich in ihrer Physiologie und Langlebigkeit. Hier untersuchen wir, ob es auch Unterschiede in deren Immunantwort gibt und nutzen Infektionen mit dem prävalenten den Deformierten Flügel Virus (DWV) als Modellsystem. Aus denselben drei weiselrichtigen Völkern im Raum Bern wurden 67 Sommer- und 50 Winterbienen gesammelt und auf die Expression von sieben Immungenen (Defensin 1, Dorsal, Eater, Juvenil Hormon, Hymenoptaecin, Prophenoloxidase und Prophenoloxidase-aktivator)und auf die Menge von DWV mittels qPCR Analyse getestet. Unserer vorläufigen Resultate deuten auf eine positive Korrelation der Stärke der Immunantwort und der Belastung durch DWV in Sommerbienen hin. Das Immunsystem von Winterbienen hingegen scheint aber eine schwächere Reaktion auf das vermehrte Vorkommen von DWV zu zeigen. Diese Ergebnisse deuten auf mögliche Unterschiede in der Immunabwehr bei Sommer- und Winterbienen hin und könnten im Zusammenhang mit deren Lebenserwartung stehen.

P42 Mating disruption of Varroa destructor in a laboratory bioassay - Störung der Paarung von Varroa destructor in einem Laborbiotest

Bettina ZiegelmannS, P. Rosenkranz (Hohenheim)

Male Varroa destructor mate almost exclusively with the youngest adult daughter within a brood cell. Previous studies showed that the observed preference is triggered by a volatile sex pheromone which is presumably released by the females shortly after moulting (Ziegelmann et al., 2013, (doi:10.1007/s13592-012-0182-5). Within the cooperation project „FITBEE“ we identified three fatty acids and the respective ethyl esters in extracts of attractive females as active components of the sex pheromone. In order to evaluate the potential of a biological control of Varroa destructor on the basis of this pheromone, we tested in the current study how the pheromone influences the male mating behavior under laboratory conditions. Therefore, mixtures of these substances were applied on filter paper in different dosages (1 ng, 10 ng, 100 ng, 1000 ng per substance) and the male copulatory responses toward The female members of a typical “Varroa family” 8 to 9 days after cell capping – consisting of a mother mite, two mature daughters, a deutochrysalis and a deutonymph – were quantified. Compared to control tests without additional pheromone, males showed for all dosages reduced copulatory responses toward the youngest mature daughter, with the maximum reduction at 100 ng per substance. Obviously, the males’ ability to recognize the “right females” within the artificial pheromone plume was reduced. Instead, an increased seeking behavior and numerous copulation attempts with immature

65

deutonymphs and deutochrysalis as well as older mature daughters could be observed. In regard to a mating disruption technique these results are quite promising and constitute a basis for first application tests in bee colonies.

P43 Competition between the intracellular pathogens Nosema apis and Nosema ceranae in the midgut of the honey bee Apis mellifera - Konkurrenz zwischen den zwei intrazellularen Krankheitserregern Nosema apis und Nosema ceranae im Mitteldarm der Honigbiene Apis mellifera

Myrsini E. NatsopoulouS, D.P. McMahon, V. Doublet, R.J. Paxton (Halle, Allg. Zool.)

Nosema apis and Nosema ceranae are two microsporidian species that commonly infect honey bees (Apis sp.). Both species are obligatory intracellular pathogens that multiply within the epithelial cells of the ventriculus of their hosts. While N. ceranae was originally detected in the Asian honey bee Apis ceranae, recent studies have demonstrated it to be an emergent parasite of the western honey bee Apis mellifera, and present in Europe since at least 1997. Moreover, due to its widespread distribution and high prevalence, it has been suggested that N. ceranae is replacing the native N. apis, at least in some host populations. As part of the Fit Bee project, we compared the growth of these two Microsporidia after challenging individual honey bees (A. mellifera) with a single Microsporidia or with both. Sequential as well as mixed in vivo infection experiments were performed using newly emerged bees, and infection levels were determined 14 days post treatment by quantitative PCR. We thereby test the asymmetry of the competition between the original versus emerging infectious microsporidian pathogen of the honey bee A. mellifera. Our results help explain why N. ceranae has become an emergent pathogen of the western honey bee worldwide. We acknowledge support of the BMELV/BLE (project: Fit Bee), the EU (project: Bee Doc) and the BBSRC’s Insect Pollinators Initiative (project: Emergent Diseases).

5. Bienenprodukte & Sonstiges P44 The German bee monitoring (DeBiMo): Residue analyses in bee bread 2005-2012 - Das Deutsche Bienenmonitoring (DeBiMo): Rückstandsanalysen in Bienenbrot 2005-2012

Annette Schroeder, D. Martens, on behalf of the cooperative partners (Hohenheim und andere)

This long-term cooperation project focuses on the monitoring of colony winter losses and their correlation with bee diseases, pesticide residues and beekeeping management. Field work and laboratory analysis are supervised and performed by 7 bee research institutes (LAVES Celle, MLU Halle, LIB Hohen Neuendorf, LAB Hohenheim, LLH Kirchhain, DlR Mayen and LWG Veitshöchheim)3. Throughout Germany about 120 beekeepers are

66

participating in the project. Each apiary provides 10 colonies for detailed data acquisition and sampling. Bee bread was sampled since 2005, preferably after the blooming period of oilseed rape (Brassica napus) and corn (Zea mays). The samples were split in two parts, one for pollen analysis and one for residue analysis. We established a multi-method (by GC-MS and LC-MS/MS) enabling the detection and quantification of more than 300 different active substances and metabolites with a detection limit of 1-10 µg/kg. We will present bee bread analysis from 2005 – 2012. The results reveal the contamination of the pollen with more than 90 different active compounds, however, nearly all in trace amounts. The most analyzed compounds belong to the fungicides, some of them in considerable high amounts. Compounds that were applied in blooming rapeseed exhibited the highest residue levels. Clothianidin and Imidacloprid (neonicotinoids with high toxicity to honey bees) could only be detected in few cases in concentrations <3 µg/kg. Toxic effects of the here analyzed pesticides on the honey bee colonies are unlikely. The possibility of synergistic and/ or chronic effects and the impact of these data on the image of bee products will be discussed. Supported by the German Federal Office for Agriculture and Food (BLE): Ref.-No.: 2810SE001-7.

P45 Beeswax residue analysis points to a repugnant historical contamination: a Flemish case study - Bienenwachs Pestizid-Analyse deutet auf eine historischer Kontamination: eine flämische Fallstudie.

Jorgen RavoetS, W. Reybroeck, T. Wenseleers, D. C. de Graaf (Gent)

Bee products can be polluted with several products, originated from beekeeping practices or agriculture. Acaricides such as coumaphos and amitraz are fat soluble and non-volatile. In general, they do not degrade in beeswax even when the wax is melted. Other pesticides are water soluble, so they can be detected in honey, beebread or bees, but not in beeswax. Recent studies indicated that pesticide residues in brood combs will have an effect on the honey bee development. They have also sub-lethal effects and make them more susceptible towards parasites. In 2012 a survey was started to monitor the health of Flemish honey bee colonies. A part of this survey included the analysis of pesticide residues in beeswax. The beeswax analysis of ten randomly selected hives at two apiaries revealed contamination of each colony with at least three different pesticides. Among them are acaricides, but also fungicides and insecticides only applied to crops. Some of them are not registered in Belgium, or even prohibited in the whole European Union.

67

P46 Increase of biomass production by Silphium perfoliatum L. for energy recovery in Austria. (Acronym: "Bioenergy-Silphium") - Erhöhung der Biomasseproduktion durch Silphium perfoliatum L. zur energetischen Verwertung in Österreich (Akronym: „Bioenergy-Silphium“).

Josef Mayr, R. Moosbeckhofer, M. Gansberger, I. Derakhshifar, H. Köglberger, A. Ribarits, K. Etter (Wien)

The reduced cultivation of flowering crops especially in areas with a high proportion of maize for biomass production reduces food sources for bees, wild bees and other insects. The widespread use of insecticides against Diabrotica virgifera virgifera in maize monocultures represents an additional risk in beekeeping. From the perspective of beekeeping and nature conservation the cultivation of alternative crops is desirable for biomass production. The experiments (2005 to 2011) of the Thüringer Landesanstalt für Landwirtschaft showed that Silphium perfoliatum L. could be such an alternative to maize. The increased cultivation would result in an expansion and enrichment of pollen and nectar offering in mid to late summer and would improve the food source for honey and wild bees and other blossom visiting insects. In Austria the project "Bioenergy-Silphium" evaluates the potential of this plant on 4 locations. Here, questions related to growing, harvesting, utilization and selective environmental effects will be examined, as well as a comparative economic assessment with other energy crops (maize, sunflower and sorghum). This project is supported by the Climate and Energy Fund within the program "NEW ENERGY 2020". An additional project on issues of use of Silphium perfoliatum L. as a food source for honey bees, wild bees and other blossom visiting insects is in planning.

P47 Interlaboratory testing of honey comparing Reference Methods and Fourier Transform Infrared Spectroscopy - Laborvergleichsuntersuchung von Honig mit Fourier-transformierter Infrarotspektroskopie und Standardverfahren

Birgit Lichtenberg-Kraag, R. Piro, B. Brinkmann, L. Piana, P. Beaune, V. Kilchenmann, C. Kast (Hohen Neuendorf, Bern)

Fourier Transform Infrared Spectroscopy (FT-IR) is a fast and reliable method for simultaneous determination of several physicochemical measurands. Furthermore, FT-IR is the ordinary analytical method used for analysis of other food products. In several laboratories, FT-IR has recently been established as routine method for honey analysis. With this study we aimed to evaluate if FT-IR analysis leads to comparable results and can be considered equivalent to the established methods even if instrument types and sample preparation are different.

68

Fructose, glucose, sucrose, pH, electrical conductivity, water content and free acidity were determined by reference and FT-IR analysis in four different laboratories. Honey samples from German ring trials as well as European unifloral honeys were analyzed. The reference methods showed good accuracy for all honey types. Average values of the reference methods were used for evaluation of the quality of the FT-IR results. In case of acacia, rape, lavender, tilia and honeydew honeys most measurands were comparable for FT-IR and reference methods, however FT-IR analysis of chestnut honey deviated a lot. In general, fructose, glucose, and moisture gave mostly comparable values with both methods. Different results obtained from FT-IR and reference methods may be related to the honey types used for FT-IR calibration in the various laboratories, rather than type of FT-IR instrumentation or sample preparation. This first interlaboratory testing shows, that FT-IR is a promising approach even for a product with a high variability of components like honey. Knowing the outliers in the ring trials, each laboratory can improve or correct its specific calibrations which should be verified in a forthcoming ring trial.

P48 Do Primitively Eusocial Wasps Thermoregulate their Nests? - Regulieren primitiv eusoziale Wespen die Temperatur ihrer Nester?

Nicole HöcherlS, Jürgen Tautz (Würzburg, ZOO II)

Nest thermoregulation of social insects is important for these species, because their larvae usually need a relatively constant temperature for an optimal development. The nest thermoregulation can be divided in active and passive. The tactics of e. g. honeybees seem to be understood, but the thermoregulation of Polistes dominulus, raises questions. These wasps build nests without any cover, which could protect the brood against cooling and overheating. To investigate the temperature development of nests depending on time of day, we used two methods. A) Recording of 24h-series by using an Infrared Camera (ThermaCAM P640; Flir Systems). The Camera was adjusted to take a picture every ten seconds. The nest has been recorded for at least 10 minutes, every two hours. 30 contiguous images were analyzed by determining 4 monitoring points per nest and ambience. Data of a weather station were acquired, to get data from outside the barn. B) Two Temperature Sensors (Thermofox; Scanntronik; measuring interval: 10 min): One sensor directly under the nest and one between nest and roof. The analysis of the Infrared Camera images shows that the nest temperature follows the ambient temperature. Although it was a cool day (in our example: maximum outside 20.6°C), the nest is ca. 2°C cooler as the ambient temperature between 10 am-6 pm. During the night (8 pm-8 am) the nest is ca. 2°C warmer. The data of the Temperature Sensors approve these results. Both methods show that a cooling of the nest takes place during the day. This result is in accordance with earlier results. During the night, the nest keeps warmer than the ambience. Because neither an active heating, nor an active cooling by the adults was observable, these temperature differences can only be explained by the architecture of the nest – a part of the passive thermoregulation. As P. dominulus-larvae develop under

69

these non-constant temperature conditions too, this species seem to be extraordinary tolerant to temperature alterations.

P49 Evidence of methylglyoxal in honey - Nachweis von Methylglyoxal in Honig

Stefan KellerS, H. Horn (Hohenheim)

Methylglyoxal (MGO) ist ein natürlicher Inhaltsstoff des Honigs. Es ist eine 1,2-Dicarbonylverbundung. Besonders hohe Konzentrationen finden sich in Manuka-Honige. Diese Honige von der neuseeländischen Südseemyrte (Leptospermum scoparium) weisen eine besonders hohe antibakterielle Wirkung auf. In dieser Arbeit wurden einheimische Sortenhonige auf ihren Gehalt an MGO untersucht. Neben den Sortenhonigen und Manuka-Honigen wurde auch ein medizinischer Honig (Medihoney®) auf Pollenzusammensetzung und MGO-Gehalt getestet. Dabei wurde geprüft, ob einheimische Sortenhonige als eine kostengünstige Alternative verwendet werden können. In einem weiteren Versuchsteil wurde die Bildung von MGO unter verschiedenen thermischen Bedingungen analysiert. Es wurde eine Vorsäulenderivatisierung mit o-Phenylendiamin (OPD) durchgeführt. MGO wurde als Chinoxalinderivat nachgewiesen. Aus 153 Honigproben konnten 6 Honigsorten mit einer Probenzahl n>10 zusammengefasst werden, mit mittleren MGO-Konzentrationen zwischen 0,7 mg/kg Honig und 2,7 mg/kg Honig. Die Gehalte des Manuka-Honigs (94,4 mg/kg Honig) und des Medihoney® (394,8 mg/kg Honig) lagen deutlich über den einheimischen Honigen. Bei den Erhitzungsversuchen zeigte sich ein Maximum nach ca. 20 Std, die Konzentration an MGO sank jedoch im weiteren Versuchsverlauf bis unter den Ausgangswert. Als Ergebnis der Arbeit lässt sich zusammenfassen, dass die Konzentration an MGO sortenspezifisch ist. Die Konzentrationen der einheimischen Sortenhonige ist jedoch deutlich geringer als die der neuseeländischen Manuka-Honige. Durch thermische Belastung kann der Gehalt an MGO leicht gesteigert werden, es gibt jedoch ein Maximum in der Konzentrationskurve.

P50 Automatic analysis of Apis mellifera comb photos and brood development - Automatische Auswertung von Apis mellifera Wabenfotos und Brutentwicklung

Benjamin Höferlin, M. Höferlin, M. Kleinhenz, H. Bargen (Osnabrück, Stuttgart, Niefern-Öschelbronn)

The software “HiveAnalyzer” (http://hiveanalyzer.visionalytics.de) has been developed to analyze the cell contents in photos of honeybee combs by means of advanced image analyzing technologies. The software speeds up the time-consuming comb analysis, reduces the risk of errors and allows tracing the complete brood development cycle in several 100 cells (e.g., OECD guidance document no. 75, 2007). Optimal image quality is

70

obtained using homogeneous, indirect illumination according to the concept of dome light and HDR (high dynamic range) photography. The software automatically adjusts photos (magnification, perspective, etc.) of the same comb taken at different times (image registration). A cascade of different tailored feature-classifier combinations (e.g., linear SVM with multi-scale Haralick features and color histograms) is used to detect the comb cells and to classify their content. To avoid mistakes, cells with low recognition confidence are marked for manual evaluation. Using a conservative classification scheme, the software recognizes 78% of all cells with high recognition confidence at a class assignment precision of 94% (measured on approx. 20000 cells with typical brood distribution, without any manual correction). Efficient manual annotation of cell content is supported by different cell visualizations. For example, crops of cell images are displayed in separate sections, sorted by class. This leverages the human recognition capability to detect wrongly classified cells as salient outliers of a presented pattern and allows correcting them. The tight integration of manual and automatic cell content analysis implements the emerging visual analytics methodology. For documentation of results, a PDF containing every individual cell and an overview of the entire comb including registration of single cells can be printed. For further processing (e.g., in Excel or SPSS), the cell data and calculated OECD-75 indices are available as data export.

P51 Seperate cells of a honeycomb for the classification of the cell content - Ausschneiden der Zellen auf einer Wabe für die Klassifikation des Zellinhalts

Steffen Mankiewicz, G. Lüth (Berlin)

Zur Beurteilung der Vitalität eines Bienenvolkes ist es notwendig in gewissen Abständen den Zellinhalt der Waben eines Bienenvolkes zu bestimmen. Insbesondere von Interesse ist dabei wie viel Brut und Honigeinlagerungen ein Bienenvolk hat. Derzeitige Schätzmethoden sind unsicher und nicht reproduzierbar. Im Rahmen des Forschungsthemas BiVi beim BMELV wurde eine Aufnahmebox entwickelt, mit der von jeder Wabe eines Bienenvolkes eine hochauflösende Aufnahme gemacht werden kann. Für die später durchzuführende Klassifikation der einzelnen Zellen ist es zuvor notwendig die Zellen auf der Wabe mit Verfahren der Bildverarbeitung zu finden. Im vorliegenden Vorschlag wurden die hochauflösenden Bilder der Wabe mit einem adaptiven Threshold binarisiert. Anschließend wurden mit Hilfe von Verfahren der Kontourfindung die einzelnen Zellen extrahiert. Ein Großteil der Zellen können mit diesen Verfahren gefunden werden. Probleme machen aber z.B. Zellen verdeckelter Brut. Hier lassen sich keine typischen Zellkonturen ermitteln. Um dennoch auch in diesen Bereichen Zellen ausschneiden zu können, wurde die Annahme getroffen, dass eine Wabe eine nahezu regelmäßige Zellstruktur aufweist. Über die gesamte Wabe kann daher ein elastisches Netz aufgespannt werden. Die Ankerpunkte des Netzes bilden die bisher gefundenen Zellen. Das Netz wird im Folgeschritt an die jeweiligen lokalen Gegebenheiten der Wabe angepasst. Diese entstehen hauptsächlich durch unterschiedliche Zellgrößen. Jede

71

einzelne zuvor nicht gefundene Zelle kann nun durch ihre Nachbarn in Abhängigkeit der Größe und Position sehr genau extrapoliert werden.

P52 Critical thermal maxima of two honeybee subspecies, Apis mellifera carnica and A. m. ligustica - Kritische thermische Maxima von zwei Honigbienen Rassen, Apis mellifera carnica und A. m. ligustica

Käfer, H., Helmut KovacS, Stabentheiner, A., Costa, C. (Graz, Bologna)

The Italian honey bee Apis mellifera ligustica (SPINOLA) originates from continental Italy. It is adapted to the warmer climate of the Mediterranean and less able to deal with cold winters and wet springs of northern temperate regions. The Carniolan honeybee Apis mellifera carnica (POLLMANN) has established and adapted to the Carniola-region (Slovenia), the southern Austrian Alps, southern Pannonian plain, Dinaric alps, and northern Balkan. It endures the harsh, long winters well in a tight cluster, and during the breeding season it quickly adjusts foraging and brood rearing to changes in weather. We investigated whether the adaptation of these neighbouring subspecies of the Western honeybee to different climates manifests in differences in physiological traits like the upper thermal limits (critical thermal maxima, CTmax). We combined IR thermography (measurement of body temperature and assessment of behaviour à activity CTmax) with a standardized thermolimit respirometry procedure (à respiratory CTmax). Experimental ambient temperature was increased up to 55 °C at a rate of 0.25 °C min-1. CTmax was defined as the temperature where controlled activity ceased (act CTmax) and cyclic CO2 production stopped (resp CTmax), respectively. Mean respiratory and activity CTmax in A. m. ligustica were higher by 1.3 and 1.2 °C than in A. m. carnica, respectively. However, the differences were not statistically significant (resp CTmax = 50.1±1.1 °C vs. 48.8±2.5 °C; p = 0.08139; act CTmax = 50.2±1.1 °C vs. 49.0±2.3 °C; p = 0.09338; t test, each test and ssp. N = 14). The amount of the thoracic heating bout, a phenomenon detectable in bees and wasps at the upper end of their viable temperature range, right after the mortal fall, was quite similar (1.8 ±1.1 °C, n=14 vs. 2.0±0.6 °C, n = 10; p = 0.56213, t test). These results suggest the CTmax of the two races to be quite similar. However, the slightly higher values of Ligustica points to a better adaptation to higher temperatures.

6. Genetik & Zucht P53 Methodological improvements regarding the centrifugation of drone semen - Methodische Verbesserungen bei der Zentrifugation von Drohnensperma

Jakob Wegener, T. May, G. Kamp, K. Bienefeld (Hohen Neuendorf, Mainz)

Centrifugation to reconcentrate diluted honey bee drone semen is required if a homogeneous mixture of ejaculates is desired, or if semen is collected via the so-called

72

“washing technique”. Several reports have found that centrifugation in existing extenders damages sperm and reduces the performance of inseminated queens. Here we tested four new centrifugation media as well as different additives (catalase, aprotinin, and egg yolk) in order to reduce damage through centrifugation. Post-centrifugation semen quality was measured by double fluorescent (“viability”-) staining and measurement of motility after resuspension in an activating medium. Two media, a hypertonic Tris-buffer and a slightly hypertonic HEPES/citrate-buffer, resulted in an improved motility after centrifugation, as compared to the literature standard. None of the tested additives brought an additional improvement. Centrifugation at 1300 x g for 12 minutes in the HEPES/Tris-buffer was found to result in an acceptable level of reconcentration and only a slight (approximately 10%) reduction in cell viability/motility. Two times two groups of five queens each were inseminated with either untreated or centrifuged semen. Nearly all queens receiving centrifuged semen produced normal brood patterns. The number of sperm reaching the spermathecae was similar to that in control animals receiving non-centrifuged semen. Although long-term observations on queen performance are required to conclude with certainty, our results suggest that the new HEPES/citrate buffer, in combination with the optimized centrifugation strength/duration, should allow for a reduction of centrifugation-related fertility losses in honey bee semen.

P54 Influence of the different time periods in which virgin queens were kept in the same ambient conditions, on their mating success level registered on the isolated island mating station of Mali Drvenik in Dalmatia - Effekt unterschiedlicher Zeitverläufe bei der Haltung von Jungköniginnen unter kontrollierten Bedingungen auf ihren Begattungserfolg auf der in Dalmatien gelegenen Inselbelegstelle Mali Drvenik

Damir Šekulja (Rijeka)

According to usual queen rearing practice, virgin queens in Apidea type mating hives should be kept in a dark and cold place for at least three days in order to allow colony members to get aquatinted and to start acting as a small colony. In practice, due to various reasons, unmated queens are often left isolated, for a shorter or a longer period of time than is recommended. The purpose of this work was to check if this has any significant impact on the field obtained mating results. In the late spring of 2012, two shipments of over 500 Apidea type mating hives each, were brought to the Dalmatian island mating station of Mali Drvenik (near Trogir) with one week’s difference between them. All mating nuclei had the same amount of bees and food, and were supplied with one day old virgin queens. They were then all left in a dark and cold, cave-like underground shelter (12⁰C) from one to six days. The Apideas were placed in numbered blocks of eight pieces. Transport was made by car trailer during the day. After transport to the island by ferry, mating hives were left open on the same

73

evening, and remained on the island for three weeks, i.e. till the appearance of the sealed worker brood. During the collection and packing of the mated queens, the mating results of all the above mentioned groups of virgin queens were checked and compared. In the cases when virgin queens were kept from two to six days in isolation the oscillations in mating success on the island were below 2%. Only in the case when queens were kept just one day in isolation, the mating success was 4.82 % lower than the average of 78.82 %. From the obtained results, it could be concluded, that in practical queen rearing terms, under given circumstances, there was no significant difference in the mating success no matter if the queens were kept isolated for one or even six days before they were left open in the field.

P55 Comparison of the re-queening acceptance level in relation to the worker bee accompaniment of the queen cages - Vergleich des Umweislungserfolgs in Abhängigkeit vom Bienenbesatz der Zusetzkäfige

Damir Šekulja (Rijeka)

Beekeepers are often confused about the choice of the best way of re-queening their colonies. In practical terms, most of them are re-queening colonies immediately after the old queen is taken away from the host colony, by adding a new queen (in a transport cage), usually together with old bees which accompany it. Common doubt is whether it would be better to introduce a new queen alone, i.e. without old bees, as it is presumed that old bees might be the reason for the rejection of the new queen. In order to check if the origin or the presence of accompanying bees would make any difference in the acceptance of the new queens, within the frame of this work, three groups of queens were formed and used for the re-queening of over 200 A.m.carnica colonies in 2012 in Rijeka, Croatia. First group was used for re-queening in a way that old bees were left in transport cages, and only the consumed food was filled prior the introduction into a host colony. The second group was formed by transferring the new queen into a new transport cage, filled with the bees from the host colony (the colony in which the queen was introduced), while the third group was left with queens with no bees at all (old bees were left out of the cage). The quality and the quantity of the food in all transport cages was the same, and so was the type of cage. Re-queening success in the first group was 86.21%, in the third group was 86.67% and only in the second group, when accompanying bees were from the colony in which the queen was introduced, it was significantly different i.e. 95.23%. According to obtained results, it was concluded that from a practical point of view, there is no need to remove the accompanying bees prior to re-queening, as the percentage of the acceptance of queens was not significantly different, but although it is more time consuming, in order to improve acceptance rate, it should be considered replacing accompanying bees with bees originating from the host colony.

74

P56 Comparison of the two different methods for determining the level of V. destructor invasion in A. m. carnica colonies - Vergleich der Genauigkeit zwei unterschiedlicher Methoden zur Bestimmung der Invasion von V. destructor in A. m. carnica Völker

T. Ivančić, V. Ljubović, Damir Šekulja (Rijeka)

To conclude if the treatment against V.destructor in brood right A.m.carnica colonies is efficient, and, if in local beekeeping conditions in Rijeka (Croatia), bees could be left untreated until the brood-less period, during the last few years a method described by Büchler et al, ADIZ, 7/2006 was successfully used. According to it, a sample of approximately 30 g of bees was collected before the treatment and after the recommended treatment period. If the percentage of V.destructor invasion was lower than 2%, then additional treatment was not needed. Recently, a new method was described by Büchler et al, ADIZ, 8/2011. According to this method, collected bee samples were not sacrificed, but were instead (after being powdered with sugar) returned back to their original colonies. As the first method required approximately 600 bees per colony, the storage of samples in a deep freezer, and time consuming laboratory work in the cases when many samples needed to be processed, the new method was instantly well accepted amongst the beekeepers. However, from a practical point of view, it was necessary to check in Rijeka’s climate, under the same conditions, whether both methods would provide the beekeeper with equal or at least similar results. On five different apiaries, approximately ten bee samples were tested in parallel (before and after Check Mite + treatment) by both methods. By the old method, the average invasion level was 0.76% before and 0.04% after the treatment, and by the new method it was 0.77% before and 0.03% after the treatment. According to the obtained results, it could be concluded that the percentage of V.destructor invasion registered by both methods was not significantly different. The last method has proven to be more weather related, because it was difficult or practically impossible to perform in rainy or windy weather. The field work was also prolonged. On the other hand, the results were immediate, and the new method required no sacrificing of bees.

P57 There are several ways to kill a honey bee larva – A model for pathogenesis of P. larvae infections - Es gibt mehr als einen Weg eine Larve zu töten – Ein Modell zur Pathogenese der P. larvae Infektion

Anne FünfhausS, L. Poppinga, E. Garcia-Gonzalez, E. Genersch

Paenibacillus larvae (P. larvae) causes American Foulbrood (AFB), a notifiable epizootic of honey bees lethal for infected larvae and most often also for diseased colonies. Four genotypes of P. larvae have been described on the basis of repetitive element PCR (repPCR) performed with ERIC-primers. These genotypes (ERIC I – IV) differ in virulence on

75

larval and colony level with P. larvae ERIC I being less virulent than P. larvae ERIC II – IV on individual larval level. P. larvae ERIC I and ERIC II are frequently isolated from AFB outbreaks all over the world while genotypes ERIC III and ERIC IV are only represented by very few historical isolates in international culture collections. Hence, P. larvae ERIC I and ERIC II are the most important genotypes from the practical point. In the recent past, the pathogenesis of infections with P. larvae ERIC I and ERIC II have been described using fluorescence in situ hybridization. Furthermore, several virulence factors of P. larvae ERIC I and ERIC II could be identified and characterized recently. Among these virulence factors were a surface layer protein (S-layer protein) SplA, two toxins, Plx1 and Plx2, and a chitin-degrading protein CBP49. Based on this descriptive and analytical information we here present a model for P. larvae pathogenesis where activity of CBP49 paves the way for SplA and Plx1/2 to act on the epithelium and to allow breaching of the epithelial layer and entering the haemocoel.

Wir bedanken uns herzlich bei allen Sponsoren und Unterstützern der 60. Jahrestagung der Institute für Bienenforschung:

76

Lageplan: Campus Am Hubland