Morphology of reproductive accessory glands in eight species of blood-feeding Hemiptera (Hemiptera, Reduviidae) insect vectors of Chagas disease

Abstract

This paper documents the morphology of previously undescribed adult reproductive accessory glands in eight species of blood-feeding Hemiptera, vectors of Chagas disease. These species are three Triatoma (T. dimidiata, T. klugi, T. sordida), three Rhodnius (R. brethesi, R. nasutus, R. pictipes), and one species each from Nesotriatoma (N. bruneri) and Panstrongylus (P. megistus). This survey shows that the male reproductive systems between species of four genera of Reduviidae adhere to the same general plan seen in previously described vectors of Chagas disease. This morphological similarity suggests that reproductive success of the male is contingent on the delivery of a vital set of male accessory gland secretions to the female in conjunction with material from the testes and seminal vesicle. However, variations were observed in the accessory glands of females, especially at the level of the genus. The spermathecae are morphologically distinct, and the posterior accessory glands are absent in some. The differences in spermathecae morphology likely reflect physiological adaptations associated with speciation driven by cryptic female choice in which the female determines which sperm are used for fertilization. Differences in the posterior reproductive accessory gland can be correlated with variations in ovipositioning behaviour. Since reproductive physiology is important for species success, this information also augments epidemiological studies by providing a comparison to R. prolixus, a Chagas disease vector for which the physiology is well known.