Conclusion
Our study found a high diversity of non-bee flower visitors, and the
primary non-bee pollinators were flies. Even though bee-mediated
pollination is important, our results suggest that non-bee species
significantly contribute to total pollination services for strawberry
crops in Ontario. On average, syrphids carried more pollen than native
bees, contextualizing their role as putative pollinators. The collective
contribution of three fly families, Syrphidae, Polleniidae and
Anthomyiidae, represented most of the active pollen within the
investigated fields. Although these families also tended to be the most
generalist foragers, their pollen loads contained large proportions of
strawberry pollen. Generalist pollinators are highly valuable in
agriculture; they contribute to the diversity of pollinators visiting
crop flowers and therefore increase pollination success, and they are
more robust in the face of ongoing landscape intensification (Ghazoul
2005, Blüthgen and Klein 2011, Garibaldi et al. 2014). Furthermore,
generalists may be more resilient to adverse weather conditions
(Heinrich and Mcclain 1986, Inouye et al. 2015). However, further
research is needed to understand the quality of pollination services of
non-bee pollinators.