Sandra Gillespie

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“Whether in natural or agro-ecosystems, researchers are increasingly viewing positive interactions such as pollination in a broader context rather than as isolated pair-wise interactions,” Gillespie says. “In natural ecosystems, my research has explored how incidence of parasites and diseases of native bumble bees may affect pollination of plants in old-field meadows in Massachusetts. High incidence of certain parasites reduced pollination of bumble bee-dependent wild plants, suggesting that parasitism may impact pollination service to native plants and crops.”

“In a more applied context, I examined the effects of field management decisions, including pesticide use and irrigation practices, on pollination service in onion seed production in California. High insecticide use, even pre-bloom, as well as reduced irrigation negatively impact pollinator visitation in this crop, highlighting the importance of considering the indirect effects of management on the pollination process in agro-ecosystems.”

Gillespie, a postdoctoral researcher at UC Davis since 2011, received her bachelor’s degree in biology from Simon Fraser University, Canada. Her doctorate, from the University of Massachusetts, Amherst, was a joint degree in organismic and evolutionary biology, and entomology.  Her doctoral dissertation, with major professor Lynn Adler, “sought to understand whether mutualisms can mediate trophic cascades, and whether the occurrence and strength of such cascades is affected by the interdependence between mutualists. I examined the context and mechanisms by which parasitoids and parasites of bumble bees can have indirect effects on pollination service to plants using a range of approaches, including field surveys, laboratory manipulations and theoretical modeling.”

As a postdoc in the Williams lab, she is applying these techniques to examine the mechanisms behind yield declines in hybrid onion seed production in California, with the goal of developing sustainable recommendations for producers.

Gillespie and Adler co-authored “Mutualisms in Trophic Cascades: Parasitism of Bumble Bees and Pollination Service to Plants,” pending publication in Ecology.

Her research on “Factors Affecting Parasite Prevalence among Wild Bumble Bees,” was published in Ecology Entomology, 2010.  She has also published her work in the American Journal of Botany  (“Variation in the Timing of Autonomous Selfing among Populations that Differ in Flower Size, Time to Reproductive Maturity, and Climate,” 2010) and Annals of the Entomological Society of America (“Laboratory Rearing of North American Tiger Beetles (Coleoptera, Carabidae: Cicindelinae,” 2011).

Pending publication in the Journal of Economic Entomology: “Insecticide Use in Hybrid Onion Seed Production Affects Pre- and Post-Pollination Processes,” by Gillespie, Neal Williams, Rachael Long and Nicola Seitz.

A recipient of several nationally competitive and specialty grants, Gillespie received a National Science Foundation Dissertation Improvement Grant in 2008, and a Natural Sciences and Engineering Research Council of Canada Post-Graduate Award in 2007. The California Garlic and Onion Growers’ Association awarded her a research grant in 2011.

Gillespie presented a seminar on “Indirect Effects of Insecticides on Pollination in Hybrid Onion Seed Production” at the 2012 meeting of the Pacific Branch of the Entomological Society of America. In 2009, her graduate student presentation on “Factors Affecting Parasitism in Bumble Bees” at the annual meeting of the Entomological Society of Canada and the Entomological Society of Manitoba won her the President’s Prize award for the best student talk.