Effect of Synthetic Juvenile Hormone on Ovarian Diapause of Culex Pipiens Mosquitoes1

Abstract

Hormonal control of ovarian diapause in Culex pipiens was studied to determine whether synthetic hormones may be employed against natural populations to disrupt hibernation. As in previous studies, ovarian follicles of C. pipiens reared at a 16-hr (long) photophase were larger than were follicles from mosquitoes reared at an 8-hr (short) photophase. Ovarian follicles of allatectomized C. pipiens reared at a long photophase were smaller than those of long-photophase nonallatectomized mosquitoes and the same size as those of short-photophase non-allatectomized mosquitoes. Oral as well as topical treatment with synthetic juvenile hormone resulted in growth of such small follicles. These observations suggest that ovarian diapause of C. pipiens is controlled by the corpora allata and that hibernation may be disrupted by feeding synthetic juvenile hormone.