An ecological digest of the small hive beetle (Aethina tumida), a symbiont in honey bee colonies (Apis mellifera)

The small hive beetle (Aethina tumida Murray) is an endemic scavenger in colonies of western honey bee subspecies (Apis mellifera L.) inhabiting sub-Saharan Africa where it only occasionally damages host colonies. Such damage is usually restricted to weakened/diseased colonies or is associated with after absconding events (all bees, including the queen, leave the hive) due to behavioral resistance mechanisms of its host. In sharp contrast, the beetle has proven deleterious to honey bee colonies in introduced ranges of the United States and Australia. With this review we synthesize the existing data in a manner that allows us to discuss the beetle's natural history from an ecological perspective. A thorough exploration of beetle ecology allows us to 1) illuminate the unique symbiotic relationship it and its host share and understand how this relationship is fostered, 2) place this relationship in context with those of other arthropods inhabiting social insect colonies, 3) understand its natural reliance on honey bee colonies, 4) predict its spread outside its native range, and 5) predict its effects on non-African honey bees and non-target species. Here we present an amalgamation of information that will contribute to a more thorough and appropriate understanding of not only small hive beetles as symbionts, but of social insect symbionts in general.