COMPARATIVE NEUROENDOCRINE CONTROL OF REPRODUCTION IN MOTHS

在交配过程中，雄虫将保幼激素(JH)传递给雌虫，刺激雌虫体内保幼激素的生物合成和释放，同时抑制JH的降解，从而刺激卵子成熟。这种作用被认为是通过大脑来调节的，包括持续释放促生长素，刺激交配的雌性翼状体(CA)产生JH，同时释放一种JH-酯酶抑制剂。我们使用气相色谱-质谱仪测定体内JH滴度的能力，以及通过CA在体外测量JH生物合成和释放的能力，结合明确的生理实验表明，我们能够确定绿色隐翅虫交配诱导产卵所涉及的机制。绿色日光夜蛾很容易获得，也很容易在实验室饲养。大量对该物种生殖生物学的研究表明，它们在生殖生理方面与其他鳞翅目昆虫相似，因此是研究鳞翅目昆虫生殖生理过程的极佳模式。这项建议的重点是研究雌性日光夜蛾体内JH滴度的动态变化，假设处女的内源性JH水平随着年龄的增长而下降，在交配时，她会产生一个影响她大脑的男性因素，并伴随着促生长激素和促性腺激素的作用。这项旨在验证这一假设的研究的具体目标是：1)确定雌性大脑-食道下神经节复合体(Brain-SEG)在交配后刺激产卵中的作用；2)测量交配和处女雌性大脑-SEG对CA的反应；以及4)测序绿色刺激素。所提出的实验结果，结合同时进行的关于绿色隐翅虫促性腺激素/类生长抑素性质的研究数据，应该可以明确地解释鳞翅目昆虫交配诱导的促性腺作用的生理学，并增加我们对动物综合生理学中神经肽和其他内分泌分泌之间相互作用的认识。该项目将与堪萨斯州立大学昆虫学系主任兼教授S.B.Ramaswamy博士密切合作实施，他还同意允许调查员使用他的实验室设施。

During copulation, Heliothis virescens males transfer juvenile hormone (JH) to females and stimulate biosynthesis and release of her endogenous JH, while inhibiting JH degradation, thus stimulating egg maturation. This effect is hypothesized to be mediated via the brain, involving continued release of allatotropins that stimulates JH production by mated female corpora allata (CA) and simultaneously release of a JH-esterase inhibitor. Our ability to determine in vivo JH titers using gas chromatography-mass spectrometry and to measure in vitro JH biosynthesis and release by CA, combined with explicit physiological experiments show allow a determination of mechanisms involved in the mating-induced egg production seen in H. virescens. Heliothis virescens moths are readily available and easily reared in the laboratory. Numerous studies on the reproductive biology of this species suggest they are similar to other leptidopterans in many aspects of their reproductive physiology and, thus, serve as an excellent model to study these processes in Lepidoptera. The focus of this proposal is to study dynamics of JH titers in female Heliothis virescens, with the hypothesis that levels of endogenous JH decline with age in the virgin female and that on mating she derives a male factor that affects her brain, with a concomitant allatotropic and gonadotropic effect. The specific objectives of the proposed research to test this hypothesis are to: 1) determine the role of the female's brain- subesophageal ganglion (brain-SEG) complex in post-mating stimulation of egg production; 2) measure response of CA from mated and virgin female brain-SEG; and 4) sequence the H. virescens allatotropin. Results from experiments proposed, combined with data from concurrent studies on the nature of allatotropin/allatostatin in H. virescens, should provide a definitive explanation of the physiology of mating-induced gonadotropism in Lepidoptera, and also increase our knowledge of the interactions between neuropeptides and other endocrine secretions in the integrative physiology of animals. This project will be implemented in close collaboration with Dr. S.B. Ramaswamy, Chair and Professor, Department of Entomology, Kansas State University, who has also agreed to allow the investigator the use of his laboratory facilities.