The Hypopharynx of Male and Female Mosquitoes

In blood-feeder female mosquitoes, the hypopharynx stylet is one part of the fascicle, the structure that pierces into the host skin during blood feeding. As other parts, the hypopharynx is a free stylet. However, since male mosquitoes do not feed blood, their mouthparts are less developed. The hypopharynx fuses with the inner wall of the labium, while maxillae and mandibles are much shorter than the labium. Only the labrum and the labium are well developed and function as food canal and its sheath, respectively. Light microscopy (LM) and scanning electron microscopy (SEM) were done to compare the hypopharynx of males of several mosquito genera and, in addition, females of autogenous mosquitoes. The hypopharynxs of males of both autogenous and anautogenous mosquitoes fuse with the labium inner wall as long as the labium length, but are distinctly different structures from the labium. Dissociation occurs on the hypopharynx of female autogenous mosquitoes: Toxorhynchites spp. have a free hypopharynx as in anautogeny mosquitoes, whereas it fuses with the labium wall in Malaya genurostris Leicester, as in male mosquitoes.