![](/wp-content/uploads/2020/12/abstractheadergraphic2019.gif)
Meeting Abstract
We observed three species of carpenter bees foraging at the chasteberry bush, Vitex agnus-castus, on the Northeast Aegean island of Lesvos (Greece). Observations were made at 30-minute intervals during a 14-hour period (sunrise to sunset). Simultaneously (but reported elsewhere) we observed activity patterns of the same bee species in the laboratory for endogenous, circadian rhythms. We found distinct patterns among the species that appeared to correspond with the size of each species. The largest bodied species, Xylocopa violacea, was most commonly seen during the earlier and later periods of the day while the smaller bodied X. iris was dominant during the middle of the day. The third species, X. oliveri, was restricted to very early or very late periods of the day, including during dim light. We predict that a mixture of ecological and genetic factors causes differences in foraging times. Larger bodied species have a physiological advantage during cooler periods of the day (given their reduced ability to radiate heat) while smaller bodied species can forage during the hottest time of day when larger species are rare or absent. Subsequent results of the thermotolerance of these species are consistent with this conclusion. Our results also suggest, however, that X. oliveri has greater endogenous constraints on its range of foraging times than the other two species. For these reasons, we believe these species represent an ideal study system for understanding the foraging dynamics of pollinators within flowering plant communities.