DYNAMICS OF JUVENILE HORMONE-MEDIATED GONADOTROPISM IN THE LEPIDOPTERA

Reproduction in moths and butterflies is a dynamic process that is inf luenced by various endogenous physiological processes and exogenous fa ctors. The Lepidoptera may be divided into four distinct groups based on their gonadotropic hormones and other reproductive and biological c haracteristics, regardless of phylogenetic relationships. Some species have integrated their reproduction tightly with the endocrine events of metamorphosis, the waxing or waning ecdysteroid levels. Other speci es rely instead on juvenile hormone (1H), in part or solely. Species o f Lepidoptera that rely on IH as the gonadotropic signal also exhibit polyandry. Several mechanisms have been suggested for the occurrence o i polyandry, including availability of male-transferred nutrients (gon adotrophic effect), need for additional sperm, and increased genetic v ariability. We propose an additional reason for polyandry observed in some lepidopterans. If a female remains a virgin, her endogenous gonad otropic signal diminishes, and eggs that have been produced already ma y be resorbed to increase longevity. During copulation, the male may t rigger a neural/humoral response in the female, thus stimulating relea se of her endogenous gonadotropic signal, JH, and/or inhibiting degrad ation of the same, whence she matures new eggs. The mating effect appe ars to act humorally on the cephalic structures in several species. Wh ether this change in JH titer is due to an effect on synthesis and rel ease by corpora allata only or occurs in conjunction with inhibition o f JH degradation is unknown. (C) 1997 Wiley-Liss, Inc.