Pollen preference of two Andrenid bees in British Columbia’s oak-savannah ecosystem


  • Julie Wray Simon Fraser University
  • Elizabeth Elle Simon Fraser University


Andrenidae, Apidae, oligolecty, pollen preference


Although understanding the dietary requirements of species is an essential component of their conservation, the extent of specialisation is unknown for most pollinators in Canada. In this paper we investigate pollen preference of two bees, Andrena angustitarsata Vierick [Hymenoptera: Andrenidae] and A. auricoma Smith.  Both species range widely throughout Western North America and associated floral records are diverse.  However, these species were primarily associated with spring-blooming Apiaceae in the oak-savannah ecosystem of Vancouver Island, BC, specifically Lomatium utriculatum [Nutt. ex Torr. & A. Gray] J.M. Coult. & Rose, L. nudicaule [Pursh] J.M. Coult. & Rose, and Sanicula crassicaulis Poepp ex. DC. Floral records and scopal pollen composition from two regions on Vancouver Island indicate specialisation in oak-savannah habitats where Apiaceae are present. Both species were also caught in low abundances in residential gardens where Apiaceae were scarce, and our results indicate they were foraging on unrelated plants with easily accessible nectar and pollen rewards. Further study of these species is needed to understand whether preferences observed locally in BC exist elsewhere in their range. Our findings contribute to understanding pollen preference in natural and urban areas, and highlight two bee species to consider for conservation action in a highly sensitive fragmented ecosystem.

Author Biographies

Julie Wray, Simon Fraser University

Dept. of Biological Sciences

Elizabeth Elle, Simon Fraser University

Dept. of Biological Sciences


Biesmeijer, J.C., Roberts, S.P.M., Reemer, M., Ohlemüller, R., Edwards, M., Peeters, T., Schaffers, A.P., Potts, S.G., Kleukers, R., Thomas, C.D., Settele, J., and Kunin, W.E. 2006. Parallel declines in pollinators and insect-pollinated plants in Britain and the Netherlands. Science, 313: 351–4. doi: 10.1126/science.1127863.

Burkle, L.A., Marlin, J.C., and Knight, T.M. 2013. Plant-pollinator interactions over 120 years: loss of species, co-occurrence and function. Science, 339: 1611–1615. doi: 10.1126/science.1232728.

Cane, J.H., and Sipes, S. 2006. Characterizing floral specialization by bees: analytical methods and a revised lexicon for oligolecty. In Plant-Pollinator Interactions: From Specialization to Generalization. Edited by N.M. Waser and J. Ollerton. The University of Chicago Press, Chicago, USA. Pp. 99–122.

Davies, K.F., Margules, C.R., and Lawrence, J.F. 2000. Which traits of species predict population declines in experimental forest fragments? Ecology, 81: 1450–1461. doi: 10.1890/0012-9658(2000)081[1450:WTOSPP]2.0.CO;2.

Dunning, J.B., Danielson, B.J., and Pulliam, H.R. 1992. Ecological processes that affect populations in complex landscapes. Oikos, 65: 169–175. doi: 10.2307/3544901.

Elle, E., Elwell, S.L., and Gielens, G.A. 2012. The use of pollination networks in conservation. Botany, 534: 525–534. doi: 10.1139/B11-111.

Fahrig, L. 2001. How much habitat is enough? Biol. Conserv., 100: 65–74. doi: 10.1016/S0006-3207(00)00208-1.

Fuchs, M.A. 2001. Towards a recovery strategy for Garry oak and associated ecosystems in Canada: Ecological assessment and literature review. Technical Report GBEI/EC-00-030.

Gielens, G.A. 2012. Pollen limitation and network asymmetry in an endangered oak-savannah ecosystem. M. Sc. thesis, Simon Fraser University, Burnaby, Canada.

Haider, M., Dorn, S., and Müller, A. 2013. Intra- and interpopulational variation in the ability of a solitary bee species to develop on non-host pollen: implications for host range expansion. Funct. Ecol., 27: 255–263. doi: 10.1111/1365-2435.12021.

Henle, K., Davies, K.F., Kleyer, M., Margules, C., and Settele, J. 2004. Predictors of species sensitivity to fragmentation. Biodivers. Conserv., 13: 207–251. doi: 10.1023/B:BIOC.0000004319.91643.9e.

LaBerge, W.E. 1989. A Revision of the Bees of the Genus Andrena of the Western Hemisphere . Part XIII . Subgenera Simandrena and Taeniandrena. Transactions of the American Entomological Society, 115: 1–56.

LaBerge, W.E., and Ribble, D.W. 1975. A Revision of the Bees of the Genus Andrena of the Western Hemisphere . Part VII . Subgenus Euandrena. Transactions of the American Entomological Society, 101: 371–446.

Linsley, E.G., and MacSwain, J.W. 1958. The significance of floral constancy among bees of the genus Diadasia (Hymenoptera, Anthophoridae). Evolution, 12: 219–223.

MacIvor, J.S., Cabral, J.M., and Packer, L. 2014. Pollen specialization by solitary bees in an urban landscape. Urban Ecosyst., 17: 139–147. doi: 10.1007/s11252-013-0321-4.

Michener, C.D. 2007. The Bees of the World, Second ed. John Hopkins Press, Baltimore, USA.

Müller, A. 1996. Host-plant specialization in Western Palearctic anthidine bees (Hymenoptera: Apoidea: Megachilidae). Ecological Monographs, 66: 235–257. doi: 10.2307/2963476

Müller, A. and Kuhlmann M. 2008. Pollen hosts of western palaearctic pees of the genus Colletes (Hymenoptera, Colletidae): the Asteraceae paradox. Biological Journal of the Linnean Society 95:719-733. doi: 10.1111/j.1095-8312.2008.01113.x

Praz, C.J., Müller, A., and Dorn, S. 2008a. Specialized bees fail to develop on non-host pollen: Do plants chemically protect their pollen? Ecology 89 (3):795-804. doi 10.1890/07-0751.1

Praz, C.J., Müller, A., and Dorn, S. 2008b. Host recognition in a pollen-specialist bee: evidence for a genetic basis. Apidologie, 39: 547–557. doi: 10.1051/apido:2008034.

Robertson, C. 1925. Heterotropic bees. Ecology 6:412-436.

Sipes, S.D., and Tepedino, V.J. 2005. Pollen-host specificity and evolutionary patterns of host switching in a clade of specialist bees (Apoidea: Diadasia). Biol. J. Linn. Soc., 86: 487–505. doi: 10.1111/j.1095-8312.2005.00544.x.

Steffan-Dewenter, I., and Tscharntke, T. 2000. Butterfly community structure in fragmented habitats. Ecol. Lett, 3: 449–456. doi: 10.1046/j.1461-0248.2000.00175.x.

Thorp, R. W. 1979. Structural, behavioral, and physiological adaptations of bees (Apoidea) for collecting pollen. Ann. Missouri Bot. Gard. 66:788-812.

Williams, N. M. 2003. Use of novel pollen species by specialist and generalist solitary bees (Hymenoptera: Megachilidae). Oecologia 134: 228-237.

Wray, J.C., and Elle, E. 2015. Flowering phenology and nesting resources influence pollinator community composition in a fragmented ecosystem. Landscape Ecol., 30: 261–272. doi: 10.1007/s10980-014-0121-0.