Morph-Dependent Cyclic JH Titer in a Wing-Polymorphic Insect: Adaptive Significance and Underlying Causes

翼多态昆虫中形态依赖性循环 JH 滴度：适应性意义和根本原因

• 批准号: 0130665
• 负责人: Anthony Zera
• 金额: $ 29.76万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0130665&HistoricalAwards=false
• 关键词: Morph; Dependent; Cyclic; JH; Titer

Some insects, such as the cricket (Gryllus firmus), are wing polymorphic (i.e., they contain both flight capable and flightless morphs). Wing polymorphism has been extensively used to investigate the hormonal control of dispersal and the evolution of endocrine regulation in insects. However, all previous studies have focused exclusively on the hormonal control of flight capability (e.g., growth of wings and flight muscles) in the laboratory. No study has investigated the endocrine regulation of flight itself, and no study has investigated the hormonal regulation of wing polymorphism in the field. Recent studies indicate that the endocrine regulation of morph-specific traits is more complex than previously expected. The key regulator of wing polymorphism is juvenile hormone (JH). In the cricket, Gryllus firmus, the mean concentration of JH is similar in the flight capable and flightless morphs, but the morphs differ in how the level of this hormone varies over time. The JH titer changes 10-50 fold during the day in the flight capable morph, but it is relatively constant in the flightless morph. This study focuses on the underlying causes and adaptive significance of daily changes in the JH titer. Prolonged elevation of the JH titer is associated with ovarian growth and with the breakdown of flight muscles--changes that are detrimental with respect to flight. This study will test the hypothesis that brief elevation of the JH titer is of sufficient duration to cause the expression of flight behaviors but of insufficent duration to cause ovarian growth or the breakdown of flight muscles. Studies will involve direct comparisons of hormone titers between morphs throughout the day and evening. The JH titer will be experimentally manipulated, and its effect on flight propensity will be monitored. Finally, physiological processes (hormone biosynthesis and degradation) that regulate morph-specific daily changes in the JH titer will be investigated. Importantly, these studies will be undertaken in both the laboratory and the field. This study will substantially enhance our understanding of the endocrine regulation of dispersal and evolution of dispersal in insects.

一些昆虫，如蟋蟀（Gryllus firmus），翅膀是多态的（也就是说，它们既有能飞的，也有不能飞的）。昆虫翅膀多态性已被广泛用于研究昆虫的激素对传播的控制和内分泌调节的进化。然而，之前所有的研究都集中在实验室中对飞行能力（如翅膀和飞行肌肉的生长）的激素控制上。目前还没有研究飞行本身的内分泌调节，也没有研究研究翅膀多态性的激素调节。最近的研究表明，内分泌对形态特异性性状的调节比以前预期的要复杂得多。羽翼多态性的关键调控因子是幼体激素（JH）。在蟋蟀Gryllus firmus中，JH的平均浓度在会飞和不会飞的变种中是相似的，但是这种激素的水平随时间的变化是不同的。在能飞型中，JH滴度在白天变化10-50倍，而在不能飞型中则相对稳定。本研究的重点是JH滴度每日变化的潜在原因和适应意义。JH滴度的长期升高与卵巢生长和飞行肌的破坏有关，这些变化对飞行是有害的。本研究将检验一个假设，即短暂的JH滴度升高足以引起飞行行为的表达，但不足以引起卵巢生长或飞行肌肉的破坏。研究将包括在白天和晚上直接比较不同形态的激素滴度。将对JH滴度进行实验操作，并监测其对飞行倾向的影响。最后，生理过程（激素的生物合成和降解）调节形态特异性每日变化的JH滴度将被研究。重要的是，这些研究将在实验室和实地进行。本研究将大大提高我们对昆虫扩散的内分泌调节和扩散进化的认识。