Foraging Patterns of Three Carpenter Bee Species at Chasteberry Bushes in an Aegean Island Ecosystem

Abstract

We recorded foraging times of three species of carpenter bees at chasteberry bushes on the Northeast Aegean island of Lesvos (Greece). These records were made at 30-minute intervals over a 14-hour period (before sunrise and after sunset). In a sister study, we observed activity patterns of the same bee species in order to elucidate any corresponding circadian rhythms. The largest bodied of the three bee species was most frequently observed during the earlier and later periods of the day while the smallest bodied species was more common during the middle of the day. The third species (mid-sized) was crepuscular in its habits. Ecological and genetic factors may both contribute to these differences in foraging times and larger bodied species may have a physiological advantage during cooler periods of the day (given their reduced ability to radiate heat) while smaller bodied species may better forage during the hottest times of day. Subsequent studies of the thermotolerance of these species are consistent with this conclusion; the crepuscular species may have more limited ranges of time for foraging than the other two species. This study system has application to broader questions concerning foraging dynamics of pollinator species within plant communities across ecosystems.