Confinement of small hive beetles (Aethina tumida) by Cape honeybees (Apis mellifera capensis)

In this study we quantify small hive beetle (Aethina tumida. Murray) and Cape honeybee (A.m. capensis Esch., an African subspecies) behaviours that are associated with beetle confinement in an effort to understand why Cape bees can withstand large beetle infestations. Four observation hives were each inoculated with 25 beetles and were observed for 11-17 days. Data collected included guard bee (worker bees who guard beetle confinement sites) and confined beetle behaviour. There was considerable colony variation for many bee and beetle behaviours. Overall, there were more beetle guards during evening, which was likely an effort to keep increasingly active beetles contained. About one-fifth of the beetles were found at the comb periphery although the colonies suffered no ill effects. Although beetles reached the combs, the bees were able to prevent beetle reproduction. Our data suggest that confinement is more likely an initial defence against invading beetles and not the sole reason African subspecies of honeybees are usually immune to beetle infestations while European bees are not.