Mandibular glands of stingless bees (Hymenoptera: Apidae): Chemical analysis of their contents and biological function in two species ofMelipona.

Workers ofMelipona fasciata andM. interrupta triplaridis respond to their respective mandibular gland extracts with alarm recruitment and defensive behavior. Workers rapidly exit from the nest entrance, land on an intruding object, and bite with the mandibles while vibrating the flight muscles. These behaviors are accompanied by the release of the contents of the mandibular glands. Colonies of both species exhibited greater response to their own mandibular gland extracts than to those of other stingless bee species. Chemical analysis identified 2-heptanol as the major component in hexane extracts of each species. Undecane was a constituent of both species; skatole and nerol were identified only in extracts ofM. i. triplaridis.