Identification of the defensive secretion from soldiers of the North American termite,Amitermes wheeleri (Desneux) (Isoptera: Termitidae).

Head capsule extracts ofAmitermes wheeleri soldiers yielded an isomeric mixture (67 μg/ soldier) of three sesquiterpene hydrocarbons identified by EIMS, [(13)C]-, and [(1)H]NMR as (+)-(S,Z)-α-bisabolene (53%), (+)-(R)-β-bisabolene (16%), and (-)-(Z)-α2-bisabolene (31%). When alarmed, the termite soldiers secreted the fluid onto the head surface surrounding the efferent pore of the frontal gland reservoir. A defensive function for the soldier secretion was indicated by the avoidance behavior displayed toward alarmed soldiers by the antagonistic ants,Pogonomyrmex rugosus andIridomyrmex humilis. Laboratory studies demonstrated that the sesquiterpene mixture is repellent to foragingI. humilis workers.