Semiochemicals from anal exudate of larvae of tsetse fliesGlossina morsitans morsitans Westwood andG. morsitans centralis Machado attract gravid females.

Tsetse flies (Diptera: Glossinidae:Glossina) mature their offspring in utero, giving birth to mature larvae that burrow into soil and pupariate. During the hot dry seasons, puparia of some species of tsetse are aggregated in areas of deep shade in dense thickets. We have confirmed the presence of a semiochemical from the prepupariation excretions of larvae ofGlossina morsitans morsitans Westwood and report a similar semiochemical inGlossina morsitans centralis Machado. These semiochemicals are attractive to gravid females and result in the aggregation of puparia. Behavioral studies withG. m. centralis showed that a higher percentage of females larviposited over moist sand conditioned by the anal exudate of larvae. Electroantennogram analyses of extracts of sand conditioned byG. m. centralis andG. m. morsitans confirmed the presence of olfactory receptors on the antennae for the semiochemicals. Both subspecies responded to extracts of the semiochemicals of the other, withG. m. morsitans more responsive to lower concentrations of extract ofG. m. centralis than the converse.