Chemical composition and efficacy of cephalic gland secretion ofArmitermes chagresi (Isoptera: Termitidae)

Soldiers of the neotropical humivorous termiteArmitermes chagresi have large ice-tong-like mandibles for mechanical defense and a moderate length nasus from which cephalic gland defensive secretions are discharged. Soldiers do not eject secretion, but ooze droplets which are held at the nasus tip by hairs. The chemical secretion is composed of C₂₂–C₂₆ macrocyclic lactones, including C₂₄ and C₂₆ and - and -hydroxylated lactones, with C₂₄ macrolides predominating. The cephalic gland secretion has no pheromonal properties and does not induce alarm or attraction in soldiers or workers. Upon application, the secretion repels and is irritating to ants, but does not appear to act as an antihealant. The defensive behavior and chemistry ofA. chagresi is discussed in light of termite ecology and evolution.