Características biológicas e moleculares na ovogênese de Anopheles darlingi Root (Diptera Culicidae)

Abstract

The mosquito Anopheles darlingi is the main vector of human malaria in Brazil. Nevertheless, little information exists on the gonotrophic cycle of this important vector, whose knowledge is important for an effecient control strategy. Therefore, this work studied the oogenesis in this mosquito species. Molecular, biologic and morphological aspects of oogenesis, before and after the blood meal (BM), were investigated in female A. darlingi collected at the suburb of Manaus and Coari city to study the. Before the BM, ovaries of female A. darlingi are small and contain few lipid vesicles. At this stage the expression of vitellogenin (Vg) gene is absent. After the BM, there were marked internal and external changes in the ovaries due to storage of yolk in the oocytes. Small granules of yolk are already observed at 3h post BM, although the expression of Vg gene was only detected at 6h post BM. The expression of Vg and their storage in the ovaries are more evident after 24 hours of BM, remaining constant between 36 to 48 hours post BM. The final dimensions of the egg are reached at 72 hours post BM when Vg gene expression decreased. Oviposition occurred at 96 hours post BM when the expression of Vg is absent. In the analyses of the frequence of blood meals taken by female A. darlingi, 80% ingested two blood meals within 24h and 75% fed three times in a period of three days, showing the ability of this species to feed more than once during a single gonotrophic cycle. An apparent increase in Vg gene expression was noticed in females taking multiple BMs.