Sex differences in the foraging behavior of a generalist hawkmoth

Within-species variation in pollinator behavior is widely observed, but
itscauses have been minimally investigated. Pollinator sex is associated
with large differ-ences in behavior that may lead to predictable
differences in flower foraging, but thisexpectation has not been
explicitly tested. We investigate sex-associated differences
innectar-foraging behavior of the hawkmothHyles lineata, using pollen on
the proboscisas a proxy for flower visitation. We tested two predictions
emerging from the literature:(1) the sexes differ in the flower species
they visit, (2) females are more specialized inflower choice. We also
examined potential drivers underlying these predictions by per-forming
field and laboratory experiments to test whether males (3) switch among
flowerspecies more frequently, or (4) fly farther and therefore encounter
more species than fe-males. Consistent with prediction (1), pollen load
composition differed between the sexes,indicative of visitation
differences. Contrary to prediction (2), females consistently car-ried
more species-rich pollen loads than males. (3) Both sexes switched between
flowerspecies at similar rates, suggesting that differences in floral
fidelity are unlikely to explainwhy females are less specialized than
males. (4) Males flew longer distances than females;coupled with larger
between-site differences in pollen composition for females, this
resultsuggests that sex differences in mobility influence foraging, and
that females may foragemore frequently and in smaller areas than males.
Together, our results demonstrate thatsex-associated foraging differences
can be large and consistent over time, and highlightthe importance of sex
as a driver of variation in pollinator behavior.