Effects of ecdysteroid agonist RH-5849 on pupal diapause of the tobacco hornworm (Manduca sexta)

✍ Scribed by Marcin Sielezniew; Bronislaw Cymborowski

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 86 KB
• Volume: 35
• Category: Article
• ISSN: 0739-4462
• DOI: 10.1002/(sici)1520-6327(1997)35:1/2<191::aid-arch17>3.0.co;2-6

✦ Synopsis

The tobacco hornworm (Manduca sexta) exhibits facultative pupal diapause which is induced by the exposure of young larval instars to short day lengths. The daily body weight of pupae kept in constant humidity and the absence of eye pigmentation, were used as good markers for diapause in this species. The nonsteroidal ecdysone agonist, RH-5849, has proven to be very effective in inducing adult development in diapausing pupae in a dose-dependent manner. It was found that injection of 0.5 µg/g of pupal weight of acetone solution of this compound resulted in immediate cessation of the diapause and led to normal adult development and emergence. Higher doses (1-2 µg/g of body weight) caused emergence of the adults having deformed wings. Doses exceeding 2.5 µg/g of pupal weight caused hyperecdysonism, resulting in abnormal premature development without emerging from pupae. RH-5849 dissolved in acetone is about 13 times more effective in breaking the diapause as compared with the ethanol solution.