Active flight results in a significant increase in body temperature (Heinrich, 1993) and juvenile hormone (JH) biosynthesis (Bühler et al., 1983; Cusson et al., 1990). For example, when female rice leaf roller Cnaphalocrocis medinalis (Guenee) were transferred from 10 to 15 C, JH biosynthesis increased within 24 h, which significantly accelerated the female's reproduction via reduction of the period from eclosion to first egg-laying and increase in mating rate,mating frequency and total fecundity