Scanning electron microscopy of the four larval instars of the lymphatic filariasis vector Culex quinquefasciatus (Say) (Diptera: Culicidae)

Since Culex pipiens quinquefasciatus is the main vector of lymphatic filariasis in tropics and subtropics, the identification and quantification of this mosquito is an important task. Scanning electron microscopy reveals that morphological changes during larval development as the number of comb scale varies greatly and their complexity increases from first to the fourth instar. Also, their structures are more complex with a varying number of subapical denticles. The amount of pecten shows modifications at different larval instars with regard to the number and complexity of their spines. The pecten teeth increase in their number and complexity during development. The number of lateral palatal brush filaments increases during larval development from the first to the fourth instar. The ventral brush of the abdominal segment X in the first and second instars is composed of two respectively three pairs of setae while the third and fourth instars have four pairs of sturdy setae.