Mosquito juvenile hormone: Identification and bioassay activity

Abstract Juvenile hormone III was identified in whole-body extracts of larval and adult Aedes aegypti . No juvenile hormone I or II was detected. The activity of juvenile hormones I, II and III, as well as two juvenile hormone analogues (methoprene, or ZR-515 and ZR-371) was examined in adults, whereas the activity of only the three naturally occurring hormones was studied in larvae. In the larval assay fourth-instar larvae were exposed to the juvenile hormones and their ability to eclose normally was measured. In the adult assay, abdomens were removed shortly after eclosion and the juvenile hormones or analogues were applied topically. Growth of the oocytes to the resting stage was measured. In larval and adult bioassays juvenile hormone I was 10 × and 25 × more active, respectively, than juvenile hormone III. The bioassay and titre data taken together suggest that juvenile hormone III is the sole physiologically necessary juvenile hormone in Aedes .