PHEROMONE RELEASE BY THE 2 FORMS OF CALLOSOBRUCHUS-MACULATUS FEMALES - EFFECTS OF AGE, TEMPERATURE AND HOST-PLANT

The influence of age, temperature and host plant on pheromone release was investigated in females of two forms of Callosobruchus maculatus ( Coleoptera: Bruchidae), referred to as the flightless form and the fli ght form. The emission of pheromone seemed to be correlated with repro ductive status: the flightless-form females which were sexually mature at emergence began to release pheromone on the first day following em ergence. The flight-form females which exhibited no reproductive activ ity at emergence also showed a delayed emission of pheromone. The temp erature conditions and the availability of host plant seeds had no app arent effect on pheromone release by the flightless form. In flight-fo rm females pheromone release was stimulated by the presence of host pl ant seeds. Temperature seemed to affect the age at which females initi ated pheromone release for the first time after emergence, pheromonal emission being brought forward slightly by higher temperature. All the se results are discussed relative to the specific environment of each form.