Chemical ecology of stingless bees.

Stingless bees (Hymenoptera, Apidae: Meliponini)represent a highly diverse group of social bees confined to the world's tropics and subtropics. They show a striking diversity of structural and behavioral adaptations and are important pollinators of tropical plants. Despite their diversity and function al importance, their ecology, and especially chemical ecology, has received relatively little attention, particularly compared to their relative the honeybee, Apis mellifera. Here, I review various aspects of the chemical ecology of stingless bees, from communication over resource allocation to defense. I list examples in which functions of specific compounds (or compound groups)have been demonstrated by behavioral experiments, and show that many aspects (e.g., queen-worker interactions, host-parasite interactions, neuronal processing etc.)remain little studied. This review further reveals that the vast majority of studies on the chemical ecology of stingless bees have been conducted in the New World, whereas studies on Old World stingless bees are still comparatively rare. Given the diversity of species, behaviors and, apparently, chemical compounds used, I suggest that stingless bees provide an ideal subject for studying how functional context and the need for species specificity may interact to shape pheromone diversifi-