Phenological synchrony between the hoary squash bee (Eucera pruinosa) and cultivated acorn squash (Cucurbita pepo) flowering is imperfect at a northern site

D Susan Willis Chan; Nigel E Raine

doi:10.1016/j.cris.2021.100022

Phenological synchrony between the hoary squash bee (Eucera pruinosa) and cultivated acorn squash (Cucurbita pepo) flowering is imperfect at a northern site

Curr Res Insect Sci. 2021 Oct 23:1:100022. doi: 10.1016/j.cris.2021.100022. eCollection 2021.

Authors

D Susan Willis Chan¹, Nigel E Raine¹

Affiliation

¹ School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.

Abstract

The phenology of crop flowering and pollinator reproduction can become asynchronous at the edge of their respective ranges. At a northern site in Peterborough County, Ontario, we evaluated offspring emergence of Cucurbita pollen specialist hoary squash bees (Eucera pruinosa) from nests in enclosures to determine their phenological synchrony with a squash crop (Cucurbita pepo). For the crop, we evaluated the percentage of bees that emerged in time to provide pollination services during the crop pollination window. For the bees, we compared the period when both male and females were present and could mate to the whole crop flowering period. We found that fewer than half the bees had emerged by the time the crop pollination window closed and only 34.1% of the flowering period of the crop could support the reproductive activities of the bees, suggesting that phenological synchrony was imperfect from the perspective of both the crop and the pollinator at this northern site.

Keywords: crop pollination; emergence; range limit; reproductive output; sex ratio.