Preimaginal vitellogenic development and repeated autogeny in Culex pusillus (Diptera: Culicidae) from Egypt.

Autogenous ovarian development was investigated in pupal and adult stages of Culex pusillus Macquart from Egypt. Vitellogenesis was initiated synchronously in > 90% of 1-d-old pupae, and primary follicles of all pupae reached stages III and IV 1 d later. All adult females oviposited their initial autogenous egg batches within 1-4 d after emergence. Females were capable of ovipositing up to four successive autogenous egg batches. The expression of repeated autogeny was confirmed by the presence of an equivalent number of dilatations and the concurrent existence of mature primary follicles and maturing secondary follicles in the same ovarioles. In addition, the total fecundity of 33% of the females that oviposited repeatedly exceeded the ovariole number of the two ovaries. This species failed to ingest a blood meal when offered a variety of hosts. Therefore, Cx. pusillus from Egypt expressed autogenous ovarian development throughout life, a characteristic apparently unique among the genus Culex.