Evolution of Integrated Phenotypic Plasticity: Geographic Variation and Genetic Constraints

小行星9806775 许多动物，包括昆虫，能够在各种各样的环境中生存和繁衍。通常，这种在不同海拔、气候和植被的地区持续存在的能力是个体对当地条件进行调整的结果，这种现象被称为表型可塑性。例如，许多昆虫物种在发育过程中响应于高营养饮食和/或高温而发育出更大的体型和更长的翅膀。这些塑料变化对当地环境的反应可能会导致生殖产量和流动性的增加，反过来，如果昆虫以人类重要的植物为食，则会导致昆虫数量增加和农业破坏。在这项研究中解决的问题涉及蝗虫如何演变的能力，调整形态特征，以当地的环境条件和功能的协调或整合的头部和身体形态的塑料变化的后果。 较小的迁徙蝗虫，Melanoplus sanquinipes，将从美国西部夏季温度不同的地区取样。这些蝗虫的后代将在高低温和高营养和低营养饮食的四种组合中饲养，以测量身体大小，头部大小，腿长和翅长的塑性变化，并量化这些性状的遗传变异。研究人员将确定来自加州、内华达州和犹他州的蝗虫种群是否具有遗传差异，以及这些种群是否具有针对它们通常不会遇到的环境条件的表型可塑性。将测量蚱蜢的跳跃、飞行、进食和产卵性能，以确定头、身体、腿和翅膀大小的协调塑性变化是否增强了蚱蜢在不同温度和食用植物环境中生存和繁殖的能力。除了回答有关蝗虫种群表型可塑性整合的具体问题外，本研究还将检验几个关于遗传变异和环境异质性在可塑性性状进化中的重要性的一般假设。

9806775 Thompson Many animals, including insects, are able to occupy and thrive in a wide variety of environments. Often this ability to persist in regions with different elevation, climate, and vegetation is the result of individual adjustments to local conditions, a phenomenon termed phenotypic plasticity. For example, many insect species develop larger body size and longer wings in response to high nutrient diets and/or high temperature during development. These plastic changes in response to local environments may cause increases in reproductive output and mobility that, in turn, cause insect population increases and agricultural damage if the insects feed on plants important to humans. The questions addressed in this research concern how grasshoppers evolve the ability to adjust morphological traits to local environmental conditions and the functional consequences of the coordination or integration of plastic changes in head and body morphology. Lesser migratory grasshoppers, Melanoplus sanquinipes, will be sampled from regions of the western United States that differ in summer temperature. Progeny of these grasshoppers will be raised in four combinations of high and low temperature and high and low nutrient diet to measure plastic changes in body size, head size, leg length, and wing length and quantify genetic variation for these traits. The investigator will determine if grasshopper populations from California, Nevada, and Utah are genetically different and whether the populations harbor phenotypic plasticity for environmental conditions they do not normally encounter. Grasshopper jumping, flight, feeding, and egg-laying performance will be measured to determine if coordinated plastic changes in head, body, leg, and wing size enhance the ability of grasshoppers to survive and reproduce in different temperature and food plant environments. In addition to answering specific questions about the integration of phenotypic plasticity in populations of grasshoppers, this research will te st several general hypotheses about the importance of genetic variation and environmental heterogeneity in the evolution of plastic traits.