Beyond the antipredatory defence: honey bee venom function as a component of social immunity

The honey bee colonies, with the relevant number of immature brood and adults, and stable, high levels of humidity and temperatures of their nests, result in suitable environments for the development of microorganisms including pathogens. In response, honey bees evolved several adaptations to face the increased risks of epidemic diseases. As the antimicrobial venom peptides of Apis mellifera are present both on the cuticle of adult bees and on the nest wax it has been recently suggested that these substances act as a social antiseptic device. Since the use of venom by honey bees in the context of social immunity needs to be more deeply investigated, we extended the study of this potential role of the venom to different species of the genus Apis (A. mellifera, Apis dorsata, Apis cerana and Apis andreniformis) using MALDI-TOF mass spectrometry techniques. In particular we investigated whether (similarly to A. mellifera) the venom is spread over the body cuticle and on the comb wax of these three Asian species. Our results confirm the idea that the venom functions are well beyond the classical stereotype of defence against predators, and suggest that the different nesting biology of these species may be related to the use of the venom in a social immunity context. The presence of antimicrobial peptides on the comb wax of the cavity-dwelling species and on the cuticle of workers of all the studied species represents a good example of "collective immunity" and a component of the "social immunity " respectively.