Vol. 37 No. 2, 1998

Juvenoid Biosynthesis by Corpora Allata of Adult Female and Male Loreyi Leafworm, Mythimna loreyi Duponchel (Lepidoptera: Noctuidae)

Rong Kou* and Meng-Ping Tu

Institute of Zoology, Academia Sinica, Taipei, Taiwan 115

Rong Kou and Meng-Ping Tu (1998) In adult female Mythimna loreyi, the maximum rate at which the corpora allata (CA) incorporate L-[methyl- 3 H]-methionine in vitro was determined to be at 7 µM methionine concentration, and the greatest hourly incorporation (3.7 pmol/h/CA) occurred during 6-h incubations; both in vitro release of juvenile hormone (JH) II and JH III by female CA were age-dependent and showed similar trends, which peaked at day 4 (2.9 pmol JH III/4 h/CA) and day 9 (5.0 pmol JH III/4 h/CA) of adulthood. For adult male CA, the greatest hourly release of juvenile hormone acid (JHA) III occurred during the 1st 2-h incubations (27.7-37.8 pmol/h/CA); the in vitro release of JHA I, Iso-JHA II, and JHA III by male CA was also age dependent; the trends of JHA I and Iso-JHA II are similar, peaking at day 3 and day 10; for JHA III, the release rate peaked at day 4 and day 10. Male CA from different time intervals of a 24-h photoperiod showed different abilities to release JHA: from 5 h into photophase and 5 h into scotophase they showed the highest release rates of JHA I and JHA III, respectively; from 1 h and 5 h into scotophase, and 3 h into photophase they showed the higher release rates of Iso-JHA II; and from any time interval showed a constant low release rate of JHA II.

Key words: Juvenile hormone, Juvenile hormone acid, Radiochemical assay.

*Correspondence: Tel: 886-2-27899541. Fax: 886-2-27858059. E-mail: kourong@gate.sinica.edu.tw