ABSTRACT
The effect of juvenile hormone [JH] and ecdysone on initiating blood meal - stimulated ovarian cycles was studied in autogenous [2[nd] ovarian cycle] and anautogenous [1[st] ovarian cycle] Cx. pipiens. Although vitellogenesis was initiated in both mosquitoes in response to ecdysone, JHI and sequential JHI-ecdysone treatments induced vitellogenesis in anautogenous females only. JHI treatment initiated vitellogenesis in Ca. 30% of anautogenous females and only half of those were able to form mature eggs. Sequential JHI- ecdysone treatment triggered vitellogenesis in 10 out of 25 anautogenous females and mature eggs were formed in three females only. In response to ecdysone, vitellogenesis in 10 out of 18 autogenous females and mature eggs were formed in two individuals. In Ca. 70% of anautogenous siblings vitellogenesis was initiated and in most of those females mature eggs were developed. Our data suggests that differences in hormone - dependent events of vitellogenesis in autogenous and anautogenous Cx. pipiens seem to be related to the regulation of ecdysteroide release