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Habitat Management for Native Pollinators
(and Natural Enemies)
Robyn McCallum, Nancy McLean and Chris Cutler November 2015
ACORN
How can we enhance agroecosystems?
Outline• What is habitat management? • How does it work? • What are some benefits of habitat management?
• Native pollinators in Atlantic Canada • Natural enemies • Biology • Their needs • How do we start thinking like them?
What are Native Pollinators?
Wild Bees• ~ 200 different bees in NS • ~ 900 different bees in Canada • ~ 20,000 worldwide
Bumble bees (Bombus)
Halictids
Image from entnemdept.ufl.edu
Image from discoverlife.org
Andrenids
Image from naturespot.org.uk
Image form bee-busy.com
Megachilids
Images from bugguide.net
Apidae
Image from beneficialbugs.org
Managed Pollinators
• Honey Bees • Alfalfa Leafcutter Bees • Bumble bees
Why are native pollinators important?
• conservation
• ‘insurance policy’
• free services- food and plant biodiversity
• challenges facing managed bees
• efficient & effective
• buzz pollination
VS
What are natural enemies?
• beneficial insects, parasitoids, predators
• Involved in pest control • E.g. beetles, wasps • Similar needs as pollinators
Why are natural enemies important?
• Biological control • Dual purpose- pollination • Nature takes care of itself
Image from atlanticpestsolutions.net
Image from ipm.iastate.edu
Native Bee Biology
Solitary vs Social Bees• Most bees are solitary • Cavity nesting, ground nesting
• Some are social - Honey bees ! hives - Bumble bees ! rodent holes
Nesting• Trees, stems, reeds,
under rocks, in old cars, in roof eaves, milk cartons
• Proximity of water
• Parasites- nesting aggregation
• Soil tillage
Food• Typically pollen & nectar from flowers, but also oils
• Specialists vs generalists
How can we manage nesting?
• Tubes for cavity-nesters
• Soil conditions for ground-nesters
How can we manage food?
• Floral plantings along field edge
• Marginal land, ditches, etc have also been used
• Provides habitat in addition to food at valuable times
• Annual and perennial wildflowers • Growing interest in “native flowers” • Important to have diversity of flowers- tongue
length, nectar rewards
• Important to note that bees and other pollinators need food throughout the season- before and after crop bloom
Nutrition
Foraging Range• Depends on body size,
species
• Affects foraging & access to flowers
• Ranges from ~100 m to 5 km
Emergence, Phenology
• Spring vs later in the season
• Varying adult life spans- weeks to months to years
• What happens if required flowers aren’t blooming at the right time? Climate change? Evolution? Tongue length example
Development• Bumble bees vs solitary bees
How do we think like bees?
• What are basic needs? Food, water,
habitat
Habitat Management
• Conservation biology ! improve availability of resources (Landis et al. 2000)
• Connecting habitat mgmt with pollinator abundance and crop yield ?
• Apple & highbush blueberry studies
Habitat ManagementPotential benefits include:
Alternative or complement to managed bees
Increased biodiversity
Increased biological
control
What Drives Conservation Biology?
Economic Factors
Conservation Concerns
What do I plant?
• Annuals & Perennials • Different bloom times • Different flower structures
• Red clover, alfalfa, sweet clover, buckwheat, black eyed susan, vetch, sunflowers
• Wild roses, goldenrod, St. John’s Wort • Phacelia? Wild bergamot? • Spring-flowering trees (willow, etc.)
• Takes time- both plant and bee establishment
Soil Prep• pH ** • Tillage • Habitat disturbance risks- mitigate with perennials
On-Farm Techniques
• Weeds for food- balancing act • Woodpiles for habitat • Setting aside poor land for flowers • Pollinator gardens
Public Concern for Native Pollinators
• Population decline? • Pesticides? • Pathogen spillover from managed hives (or vice
versa??) • Lack of habitat ** • Lack of food (flowers) **
Enhancing Native Pollinators and Natural Enemies in Wild
Blueberry Agroecosystems
• Many crops require pollinators for fruit set • Pollinator services from managed bees = high input
costs • Native pollinators are efficient, effective and already
present (Javorek et al. 2002)
Background
• Native pollinators provide important ‘free’ services
• Populations could be increased to become more economically important
Lowbush Blueberry
• Requires cross pollination • Pollination services can be #1 cost (honey bees, other
managed bees) • Unique cropping system (crop vs sprout) • Opportunity to enhance agroecosystem for pollinators
• Techniques to boost native pollinators & natural enemies
• Focused on habitat and food
Objectives
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
Buckwheat
• Can we plant buckwheat around the field to provide food after blueberry bloom?
Buckwheat
• Annual • Can tolerate low pH • Tolerates poor soil fertility • Improves soil structure • Doesn’t spread • Attractive to bees • Long blooming period • Used for honey bees
Buckwheat
Data Collection
Buckwheat results so far
Challenges• Producer inputs !tillage, seed, management (no spray), need to plant each year, perhaps 2x per season
• Drought • Deer
• Economic benefits? • Conservation benefits?
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
Operation Pollinator
• Mixture of annuals and perennials • Can we measure nectar content? • What is persistence like, weed invasion, etc?
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
• Trap nests for Osmia species (Hymenoptera: Megachilidae)
• Cavity-nesting bee, readily accepts artificial nests
• Known to be good pollinators
Habitat Management for Mason Bees
• Solitary
• 8-9 species involved in blueberry (Stubbs et al. 1997)
• Queen lays eggs on pollen provision, larva ! pupa ! emerges the next year (Torchio 1989; Bosch et al. 2001)
• Linear sequence of ‘cells’
Osmia Biology
• Adult life span! 3- 5 weeks • Can fly @ low temps and emerge early in season • Need mud to ‘cap’ their nests, so water source important
Osmia Biology
www.bugguide.net
• What species are involved? • Does nesting uptake differ from crop field
to sprout field? • When does nesting occur? • Are nests parasitized?
Questions
• 80 trap nests in 4 fields (64 wooden, 16 milk cartons)
• Placed 10 m apart along field edge and facing the sun, supported on stakes
• Set out 22 April in crop fields in northeastern Nova Scotia
Materials & Methods- 2014
Wooden Trap Nests
• Examined different hole diameters, rain cover, burning
• Tubes were 10 cm deep
• 12 tubes/ 2L carton • Tubes = 15 cm long • Varying diameters (7 and 9 mm) • Tubes from rolled white paper + newspaper and placed
through high-density polystyrene foam; spray foam insulation to support tubes (Sheffield et al. 2007)
• Cartons painted white
Milk Cartons
Results 2014Nesting Success
%
Succ
ess
0
18
35
53
70
Nest Typemilk carton wooden
• n =
n = 14
• Focused on milk cartons only • Compared crop and sprout
Materials & Methods- 2015
• Modified design • 16 tubes instead of 12 • All the same diameter (7 mm) • Added plastic straws
Milk Cartons- 2015
• 26/32 milk cartons had capped nests (81%) • 4 milk cartons were removed due to bear
damage
Results & Discussion- 2015
Question: Crop vs Sprout
• No significant difference
• Trade offs for nearby crop/sprout rotations (bees & pests)
Question: Timing
Phenology of Osmia Nesting in 2015
Tota
l # C
appe
d N
ests
0
35
70
105
140
Date12-Jun 26-Jun 1-Jul 10-Jul 17-Jul 22-Jul 31-Jul
• Blueberry Bloom
Question: Timing• Capped nests appeared
after blueberry bloom had finished
• Not all tubes were capped at the ends
• Queens likely nested in more than one tube
• TBD, as well as species of Osmia
Question: Parasitism
• Why are milk cartons attractive? -Longer tubes -Smell? -Pink Styrofoam? White carton?
• Landscape factors- water sources, previous populations, food throughout season
Discussion 2015
Implications for Industry & Science
• Better understanding of Osmia nesting biology & involvement in wild blueberry
• Nests could be moved to crop fields requiring pollinators
• Practical, inexpensive technique
Implications for Industry & Science
• More efficient pollination
• Biodiversity conservation
• Alternative & complement to managed bees
Diversity of pollinators demands a diversity of habitat management techniques
Global Importance• $ for farmers in Europe who implement
bee-friendly practices • Marketing strategy for US farms “bee
friendly farms” • “bee friendly” product labeling
Community Engagement
• Fact sheets for blueberry production • OP seed mix fact sheet • 4H pollinator project development • Grower field days • Industry meetings • Schools • Garden Clubs
Agvocate Challenge• We need more positive ag stories! • First blossom, bees, tractors, people • Use opportunity to share
Resources
• Lawrence Packer Lab, York University
• Sheila Colla- online resources • Nova Scotia Dept of Ag handout
re: bees • Discover Life • Bug Guide
AcknowledgementsCommittee Members
Dr. Paul Hoekstra, Syngenta Blueberry Producers of NS for Field Sites
Snake Patrol
