Pollen transport by male stingless bees

Abstract

Only female bees actively collect pollen, which they use to provision brood. Although male bees also visit flowers for nectar and thus may passively vector pollen, the contribution of males to pollination services is poorly documented for most bee species. We investigated pollen transport by males of the Australian stingless bee Tetragonula carbonaria. We found that almost all males sampled at mating aggregations had pollen on their bodies, and that the quantity and diversity of pollen grains on males was similar to that found on nectar-foraging workers. We then assessed behavioural differences between males and workers which might influence pollen acquisition and retention. We found that both sexes behaved similarly while foraging on flowers, regularly contacting the flower’s reproductive structures. Both males and workers also groomed themselves to remove excess pollen, but in the morning males tended to have more pollen grains left on their bodies from the previous day’s foraging. This is presumably because workers (but not males) are allogroomed by their sisters in the nest and thus more efficient at removing pollen overnight. In all, our results suggest that male T. carbonaria may contribute to the pollination of a range of native plants and indicate possible sex differences in pollen transport by stingless bees. In particular, as male stingless bees remove less pollen from their bodies overnight and traverse far greater distances in their lifetimes, they may be more likely than workers to move pollen between fragmented plant communities.