INTERACTION OF PHEROMONES DURING FOOD EXPLOITATION BY THE TERMITE SCHEDORHINOTERMES LAMANIANUS

Chemical signals from secretions of different exocrine glands modulate a variety of behavioural patterns in termite societies. These signals have multiple functions and may be interactive. During food exploitat ion workers of the African termite Schedorhinotermes lamanianus (Isopt era: Rhinotermitidae) employ, on foraging trails, the secretion from t he sternal gland both for orientation and recruitment to a food source . The secretion from the labial gland, released onto the food by gnawi ng termites, stimulates additional workers to gnaw at the same site, t hereby forming aggregations of gnawing termites. An interaction betwee n these two pheromones during food exploitation is demonstrated for th e first time. The volatile signal from the sternal gland inhibits in a dose-dependent manner the non-volatile, highly persistent, signal fro m the labial gland. The development of gnawing aggregations is inhibit ed and established ones are dissolved. Behavioural evidence for the pe rception of both the volatile signal from the sternal gland by olfacto ry neurones and of the non-volatile signal from the labial gland by gu statory neurones on the antennae is given. The interaction of the two pheromones as a basis for the development of distinct commuting and gn awing zones on the food source, and as a means for a dynamic regulatio n of food exploitation, is discussed.