Open Collections

Tuttle, Sasha

University of British Columbia

Insects are in decline worldwide, with Hymenoptera being especially affected. Pollinator decline is driven by conventional farming practices such as intensive insecticide and herbicide use that negatively affect pollinator health and limit the availability of floral resources. With agricultural intensification and habitat loss further driving pollinator decline, growers have begun to rely on managed honey bees (Apis mellifera) to meet the pollination needs of their crops. Honey bees, however, cannot pollinate certain crops as effectively as wild pollinators. Highbush blueberry (Vaccinium corymbosum), a widely grown crop in British Columbia (BC), Canada, is one such crop that benefits from pollination by wild Bombus species. BC blueberry growers have previously been found to face limited crop yields and revenue due to insufficient pollination, but it is unknown how pollination limitation is affected by blueberry varieties and management practices. Research on other methods for growers to maximize yield, such as inter-varietal block design is also limited. I conducted a two year study on highbush blueberry fields with varying management practices within the Lower Mainland of BC. I ran pollen limitation experiments along transects set at varying distances from the field’s edge and surveyed pollinators visiting blueberry flowers on these transects to determine which taxa contributed the most to pollination. I also ran a pilot study in which I evaluated the effects of inter-varietal pollination on two different blueberry varieties. Results indicated fruit set and weight deficits are strongly related to bumble bee visitation rather than honey bee visitation and that growers who used clover as a cover crop experienced higher visitation than growers who did not. It was also found that growers may further increase yield by considering inter-varietal pollination during block design, but the level of yield increase depends on the blueberry varieties involved. These findings indicate that establishing floral resources beyond those offered by crops can encourage pollination services from wild Bombus sp., adding to a growing body of evidence that diversification of agricultural land can promote ecosystem services while contributing to conservation.

Text

2022-12-22

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/83477

Zoology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/