Ovarian development in females of Triatoma sordida Stal (Hemiptera: Reduviidae: Triatominae) under fasting conditions

RODRÍGUEZ C, AGUIRRE S, NATTERO J, CANAVOSO L, CROCCO L

Congreso; XXIV International Congress of Entomology; 2012

Triatoma sordida is a secondary vector of Trypanosoma cruzi - causative agent of Chagas disease - considered a species of epidemiological importance. It is often found in peridomestic habitat and frequently invade and colonize human dwellings. The study of aspects of the reproductive capacity of these species is relevant for the relationship with colonization of new habitat. The object of the present work was to characterize through morphometric and histological studies the ovarian development in females of T. sordida in absence of food and mating, which were killed at different days post-ecdysis. Morphological changes of the ovaries were estimated by morphometric analysis of basal follicle of each ovariole and oocytes number for different phases of oogenesis. For histological study the ovaries were embedded in paraffin, processed routinely for hematoxylin? eosin. The results indicate that T. sordida presents a quantitative pattern appropriate to identify the three phases of oogenesis. The mean length of basal follicle varied between different phases (0.358±0.096 mm previtellogenesis, 0.638±0.331 mm vitellogenesis and 1.929±0.136 mm coriogenesis). At the 2nd day post-ecdysis 100% of the females showed previtellogenic oocytes and 50% showed vitelogenic oocytes at the 4th day. The coriogenic and ovulation process began at 8th day post-ecdysis, it is suggested the end of the first gonadotrophic cycle. The morphological changes observed in the basal follicles were consistent with the results of histological analysis. These results would indicate that at 6 days post-ecdysis females of T. sordida, without feeding, have eggs ready to be oviposited.