INVITRO BIOSYNTHESIS OF JUVENILE-HORMONE BY CORPORA ALLATA OF PSEUDALETIA-UNIPUNCTA VIRGIN FEMALES AS A FUNCTION OF AGE, ENVIRONMENTAL-CONDITIONS, CALLING BEHAVIOR AND OVARIAN DEVELOPMENT

Corpora allata of Pseudaletia unipuncta females, incubated in a medium containing l-[methyl-3H]-methionine released three radiolabelled products co-eluting with synthetic juvenile hormones I, II, and III (3:6.3:0.7) on HPLC. No juvenile hormone acid was released in vitro. Rates of juvenile hormone biosynthesis (juvenile hormones I+II+III produced) were low (< 1.0 pmol h-1/pair) in newly-emerged and 1-day-old P. unipuncta females, peaked in 3-day-old individuals (7.1 ± 1.8 pmol h-1/pair), and then underwent a slight decline from day 4 to day 6, in adults reared at 25°C, 16 h light-8 h dark. Two-day-old females, calling for the first time, displayed higher rates of juvenile hormone production than non-calling females of the same age. Females whose basal oöcytes did not exceed 0.32 mm in diameter produced less juvenile hormone (< 1.0 pmol h-1/pair) than those having larger ones. There was a delay in the activation of the corpora allata of females reared as adults at 10°C, 12 h light-12 h dark; on day 5 rates of juvenile hormone biosynthesis were still the same as those determined at emergence. Rates then increased slowly and reached 3.0 ± 0.6 pmol h-1/pair on day 34. © 1990.