Behavior of honey bees (Apis mellifera) and beetle invaders at the nest entrance and within the nest

We performed two experiments to determine 1) the behavior of European honey bee guards (Apis mellifera) toward beetle invaders exhibiting various levels of integration and 2) the behavior of the beetle invaders after entering the nest. In the first experiment, we used 5 species of nitidulid beetles and 1 tenebrionid beetle. These species included Aethina tumida (highly integrated), Lobiopa insularis and Epuraea luteola (accidentals), and Carpophilus humeralis, Carpophilus hemipterus, and Tribolium castaneum (non-integrated). Guard bee responses to a control bead also were noted. The subjects were introduced individually into a test arena at the entrance of an observation hive where they were confined with guard bees. Bee responses to beetles or beads were observed for 60 s. In general, bees ignored T. castaneum and E. luteola at a higher rate than they did the other species. Bees contacted (a non-aggressive behavior) the bead moreso than they did all beetle species. Bees treated A. tumida more defensively than they treated any other beetle species. In the second experiment, beetle species were introduced at the colony entrance and their subsequent locations within the nest were recorded at regular intervals. Aethina tumida was the only beetle regularly found “hiding” (inaccessible to the bees) around the perimeter of the colony rather than leaving the nest. The data suggest that, despite a heightened defensive response by bees toward A. tumida at the nest entrance, this highly integrated species was the only beetle to move into and inhabit the colony.