LOCATION AND ULTRASTRUCTURE OF SEX-PHEROMONE GLANDS IN FEMALE CALLOSOBRUCHUS-MACULATUS (FABRICIUS) (COLEOPTERA, BRUCHIDAE)

The ultrastructure of the female sex pheromone glands in Callosobruchu s maculatus (Coleoptera: Bruchidae) were localized using a masking tec hnique, combined with electroantennography and by a comparison of the glandular sells of sexually active (flightless) females and non-sexual ly active (flight-form) females. Each unicellular gland is an invagina tion of the integumental membrane capped by a single secretory cell. T hese glands are situated on the fine intersegmental membrane, which jo ins the pygidium to the ovipositor. The secretory cells of the glands of active females are characterized by well-developed microvilli, with many elongated mitochondria among the latter. The high metabolic acti vity of these cells is revealed by the presence of heterogeneous secre tion vesicles, some of which contain abundant crystallized material. D eep basal invaginations indicate the uptake of substances from :he hae molymph. The receptor canal is a network of fine cuticular filaments w hich have the same structure regardless of the female's sexual status. Cells from the glands of non-sexually active females are underdevelop ed and show no invaginations of the basai membrane and very few microv illi. The localization of these glands was made possible by the use of SEM, TEM and EAG as well as by masking the suspected zones and by com paring females in different physiological stales: flightless females, which were sexually active and producing pheromones; and flight-form f emales, nonsexually active and producing no sex pheromones. Only by ad opting such a stringent method was it possible to confirm the function of the glands whose ultrastructure was studied. (C) 1997 Published by Elsevier Science Ltd.