Defensive behaviour and chemical deterrence against ants in the stingless bee genus Trigona (Apidae, Meliponini)
Lars Lehmberg, Kai Dworschak, Nico Blüthgen
Five species of Trigona (Apidae, Meliponini) in Borneo were tested for anti-predator deterrents, which potentially contribute to the protection of individual bees as well as their colony. Feeding choice experiments were performed with three predatory ant species. In most cases, ants significantly preferred bees that were washed with solvents (hexane and chloroform respectively) over untreated bees. This shows that stingless bees possess ant-deterrent substances. We suggest that plant-originated terpenes on the bees’ cuticles contribute to this deterrent effect. Furthermore, we observed behavioral defences of two Trigona species at their colony entrance. Upon simulated nest intrusion of ant workers, bees predominantly reacted with aggressive biting, but also utilized resin-like substances as glue against intruders. Therefore, stingless bees utilize a combination of defences that may help to deter ants as potential predators inside and outside the nest.