Sex differences in pollinator behavior: Patterns across species and consequences for the mutualism.

Intraspecific variation in floral visitor behaviour and pollination efficiency has been much less studied than interspecific variation. Nevertheless, it is clear that large differences in these traits exist within species, and in particular between sexes within species. With the exception of a few well-studied interactions, however, the consequences of these differences in the pollinators and visited plants remain to be investigated. In this review, we document large and consistent differences in the foraging patterns of male and female pollinators that have been demonstrated to directly affect plant reproduction or that have clear potential to do so. Males and females differ in visitation frequency, type of flowers visited, and per-visit pollen transfer. Females gather more and different resources from flowers compared to males, and males generally tend to show more mobile foraging patterns than females. We argue that these sex-associated patterns have broad generality across pollinators, and that sex-associated differences can in some cases be larger than differences between species. We offer predictions about how these patterns will influence pollinator preference, specialization, and fidelity, as well as the cost, quality and quantity of pollination service to plants. In the face of increasing threats to plant-pollinator interactions, understanding their basic functioning and the variation inherent in their component parts is critical. We advocate for more attention to sex-based differences among pollinators in particular, and the consequences of intraspecific variation more broadly.