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Phoretic Deutonymphs of Schwiebea sp. (Acari:Astigmata: Acaridae) Travel in Commodious NitidDorsal Pits of Adult Lagocheirus araneiformisstroheckeri Dillon (Coleoptera: Cerambycidae:Lamiinae) in Florida, U.S.A.Author(s): Foster Forbes Purrington and Cathy J. DrakeSource: Entomological News, 119(4):415-419. 2008.Published By: The American Entomological SocietyDOI: http://dx.doi.org/10.3157/0013-872X-119.4.415URL: http://www.bioone.org/doi/full/10.3157/0013-872X-119.4.415

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PHORETIC DEUTONYMPHS OF SCHWIEBEA SP.(ACARI: ASTIGMATA: ACARIDAE)

TRAVEL IN COMMODIOUS NITID DORSAL PITS OFADULT LAGOCHEIRUS ARANEIFORMIS STROHECKERI

DILLON (COLEOPTERA: CERAMBYCIDAE: LAMIINAE) IN FLORIDA, U.S.A1

Foster Forbes Purrington2 and Cathy J. Drake3

ABSTRACT: Smooth-floored asetose pits on the pronotum and elytra of adult longicornbeetles, Lagocheirus araneiformis stroheckeri, are used for dispersal by Schwiebea sp.phoretic mites anchored in them with caudo-ventral suckers. Manifest suitability of thepits for transporting these mites, demonstrated by dimensions, shape, surface structureand a high occupancy rate connotes a beetle/mite mutualism, supported by their congru-ent life histories.

KEY WORDS: Acaridae, deutonymphs, Schwiebea, phoresy, longicorn beetles, mites

Mites in many families of the Astigmata (Acari: Sarcoptiformes) produce anon-feeding pre-adult deutonymph phoretic stage which is typically dorso-ven-trally flattened, heavily sclerotized, and that in taxa using arthropod phorontsusually bears a prominent array of caudo-ventral suckers (MacNulty, 1971; Lind-quist, 1975; OConnor, 1982; Athias-Binche, 1991; Houck and OConnor, 1991;OConnor, 1994; Walter and Proctor, 1999). We found that adults of the largelongicorn beetle, Lagocheirus araneiformis stroheckeri Dillon (Coleoptera:Cerambycidae: Lamiinae), recorded only from dead wood of gumbo limbo tree(Bursera simaruba (L.) Sargent (Burseraceae) (Linsley and Chemsak, 1995),commonly bear many limuloid deutonymphs (Figures 1A, 1B) of Schwiebea sp.(Acari: Astigmata: Acaridae: Rhizoglyphinae).

This beetle subspecies is distributed in southern Florida and Cuba (Linsleyand Chemsak, 1995). The mites are attached via paraproctal caudo-ventral suck-ers (Figure 2; for sucker plate structure nomenclature see Fashing and Chua,2002) inside deep smooth-bottomed asetose pits on the pronotum and elytra.High mite occupancy rates in these pits and their frequency of occurrence on bee-tle phoronts, together with structural details of the pits, co-occurrence of beetlelarvae and mites in the same microhabitat, and the specificity of decayed gumbolimbo wood as trophic substrate for both imply a co-evolution that has shaped thebeetles’ dorsal pits.

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______________________________1 Received on January 18, 2008. Accepted on February 25, 2008.2 Department of Entomology, Ohio State University, 400 Aronoff Lab, 318 W. 12th Avenue, Colum-bus, Ohio 43210 U.S.A. E-mail: purrington.1@osu.edu.

3 Department of Evolution, Ecology, and Organismal Biology, 300 Aronoff Lab, 318 W. 12th Avenue,Columbus, Ohio 43210 U.S.A. E-mail: drake.2@osu.edu.

Mailed on November 12, 2008

416 ENTOMOLOGICAL NEWS

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METHODSWe collected a series of Lagocheirus araneiformis stroheckeri adults on Big

Pine Key (Monroe County, Florida) in 2002 and following years. Others eclosedin our Ohio State University (O.S.U.) laboratory in Columbus from pieces ofdecayed gumbo limbo wood taken from the same Florida location. Additionalspecimens were borrowed from the Charles A. Triplehorn Insect Collection in theMuseum of Biological Diversity at O.S.U., and from private collections.

We obtained scanning electron micrographs (SEM) at the Campus Micro-scopy and Imaging Facility (CMIF) at O.S.U. Specimens for SEM imaging weretaken from a single female beetle that eclosed in April 2006 at O.S.U. They weresputter-coated in a Cressington 108 with gold-palladium and examined with anFEI NOVA nanoSEM 400 scanning electron microscope.

Mites were determined by Barry M. OConnor, Museum of Zoology, Univer-sity of Michigan, Ann Arbor.

RESULTS AND DISCUSSIONDorsal pits of two types exist on Lagocheirus araneiformis: large asetose pits

and smaller pits each bearing a long erect central seta (Figure 3). The largest pitsare arrayed along the dorsal and lateral anterior and posterior pronotal marginsand over the basal third of the elytra; asetose elytral pits diminish in size apical-ly and deutonymphs generally are not found in any pits of the posterior half ofelytra.

On most beetles examined, Schwiebea sp. phoretics occupied only pronotal,and external dorsal and lateral pits of elytra. In a few beetles, a few of these mitesalso were attached upon and within clusters of Uropodidae (Acari: Mesostig-mata: Uropodina) deutonymphs attached laterally on the beetle pronotum withcharacteristic hyaline para-anal pedicels, on the ventral surfaces of the elytraalong with uropodines, or elsewhere on the mesonotum and abdominal tergitesunderneath the flight wings. Some dorsal pits were occupied by more than oneSchwiebea sp. phoretic, some by two, rarely three. Some beetles carried circa 75deutonymphs in external pronotal and elytral surface pits.

Other acarids in the Rhizoglyphinae with close beetle associations include theNearctic Bolitoglyphus ornatus (Fain and Ide), which uses as phoront the beetlepolypore fungus specialist Bolitotherus cornutus (Panzer) (Coleoptera:Tenebrionidae), and the Palearctic mite Bolitoglyphus bolitophagi (Turk) on thebeetle Bolitophagus reticulatus (L.) (Tenebrionidae). Like their beetle trans-porteurs, adults of both these mite species are polypore mycovores, and theirdeutonymphs are transported in large asetose dorsal elytral pits (Fain and Ide,1976; OConnor, 1984). OConnor (1984) points to such cases of mite/beetlestructural and feeding site conformity as possible evidence of co-evolution.

We suggest the evident congruence of the longicorn/mite relationship we out-line here parallels these other reported cases. Structural accommodations mani-fested by the deep dorsal pits generated by Lagocheirus adults are likely driven

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by beneficial trophic conditions that these mites satisfy for them. Schwiebea sp.feeding stages, elongate cylindrical larvae that tunnel in vascular bundles (BarryM. OConnor, in littorem) of dead gumbo limbo tree wood, probably conditionthe fungal/cellulose substrate on which the tunneling longicorn larvae feed.

ACKNOWLEDGMENTS

We thank Barry OConnor (Museum of Zoology, University of Michigan) for his perspicaciousinsights and for identifying the Schwiebea specimens; Hans Klompen (Museum of Biological Diver-sity, O.S.U), Norm Fashing (Department of Biology, College of William and Mary), Heather Proctor(Department of Biological Sciences, University of Alberta), and Chuck Triplehorn (Department ofEntomology, O.S.U.) provided valuable comments and helped with obscure literature. CreightonFreeman (Museum of Biological Diversity, O.S.U.) kindly arranged a loan of Lagocheirus speci-mens. Brian Kemmenoe (Campus Microscopy and Imaging Facility, O.S.U.) provided the crisp SEMimagery. We appreciate the generous technical support of Barb Shardy and Andrea Prouty (Depart-ment of Evolution, Ecology, and Organismal Biology, O.S.U.). We gratefully acknowledge financialsupport from the Department of Entomology, O.S.U. Monica Farfan and Dave Horn (O.S.U.) re-viewed an early draft of the manuscript.

LITERATURE CITEDAthias-Binche, F. 1991. Evolutionary ecology of dispersal in mites, pp. 27-41. In, F. Dusbabek and

V. Bukva (Editors). Modern Acarology. Volume 1. SPB Academic Publications, The Hague.651 pp.

Fain, A. and G. S. Ide. 1976. A new genus and species of Acaridae (Acari) phoretic on the beetleBolitotherus cornutus (Panzer, 1794). Entomological News 87: 233-236.

Fashing, N. J. and T. H. Chua. 2002. Systematics and ecology of Naiadacarus nepenthicola, anew species of Acaridae (Acari: Astigmata) inhabiting the pitchers of Nepenthes bicalcarataHook. F. in Brunei Darussalam. International Journal of Acarology 28(2): 157-167.

Houck, M. A. and B. M. OConnor. 1991. Ecological and evolutionary significance of phoresy inthe Astigmata. Annual Review of Entomology 36: 611-636.

Lindquist, E. E. 1975. Associations between mites and other arthropods in forest floor habitats.Canadian Entomologist 107: 425-437.

Linsley, E. G. and J. A. Chemsak. 1995. The Cerambycidae of North America, Part VII, No. 2:Taxonomy and classification of the subfamily Lamiinae tribes Acanthocinini through Hemilo-phini. University of California Publications in Entomology Volume 114. University of CaliforniaPress, Berkeley and Los Angeles. 292 pp.

MacNulty, B. J. 1971. An introduction to the study of Acari-Insecta associations. Proceedings andTransactions of the British Entomological and Natural History Society (4): 46-70.

OConnor, B. M. 1982. Evolutionary ecology of astigmatid mites. Annual Review of Entomology27: 385-409.

OConnor, B. M. 1984. Acarine-fungal relationships: the evolution of symbiotic associations. pp.354-381. In, Fungus-Insect Relationships. Q. Wheeler and M. Blackwell (Editors). ColumbiaUniversity Press, New York. 514 pp.

OConnor, B. M. 1994. Life-history modifications in astigmatid mites. pp. 136-159. In, M. A.Houck (Editor). Mites: Ecological and Evolutionary Analyses of Life-History Patterns. Chapmanand Hall. New York, NY, U.S.A. 357 pp.

Walter, D. E. and H. C. Proctor. 1999. Mites: Ecology, Evolution, and Behaviour. CABI Pub-lishing. New York, NY, U.S.A. 322 pp.

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