RUI Collaborative Proposal: Biochemical and Physiological Mechanisms of Thermal Adaptation in a Montane Insect Herbivore

本研究调查了高海拔地区叶甲虫金翅虫种群的进化。内华达山脉（加利福尼亚州）的种群位于该物种活动范围的南部边缘。先前的研究发现，排水系统因气温而异，甲虫数量随气候变化而波动。不同形式（基因型）的温度敏感酶磷酸葡萄糖异构酶（PGI）的频率在不同的排水中存在差异，表明自然选择作用于PGI。甲虫体内的热休克蛋白（Hsp）水平与空气温差有关，并与PGI基因型有关。本研究将探讨温度与PGI基因型功能特性之间的关系（即它们催化代谢基础生化反应的能力）。其次，以热敏感蛋白和泛素偶联物为生理胁迫指标，研究温度对不同PGI基因型甲虫生理的影响。第三，比较不同PGI基因型甲虫在自然界的生存和繁殖情况。该研究将为酶多态性的进化意义提供重要信息。这可能会增加人们对气候变化对本地昆虫影响的认识。最后，它将允许本科生参与基础研究，增强他们的教育经验，扩大他们未来的机会

This research investigates evolution in high elevation populations of the leaf beetle Chrysomela aeneicollis. Populations in the Sierra Nevada (California) are on the southern edge of the species' range. Previous studies found that drainages differ in air temperature and beetle populations fluctuate with changes in climate. Frequencies of different forms (genotypes) of the temperature-sensitive enzyme phosphoglucose isomerase (PGI) vary among drainages, suggesting that natural selection acts on PGI. Heat shock protein (Hsp) levels in beetles correspond to air temperature differences and depend on PGI genotype. The proposed research will investigate the relationship between temperature and functional property of PGI genotypes (i.e. their ability to catalyze biochemical reactions fundamental to metabolism). Second, the effects of temperature on the physiology of beetles of different PGI genotype will be studied, using Hsp's and ubiquitin conjugates as indices of physiological stress. Third, survival and reproduction of beetles of different PGI genotype in nature will be compared. The research will provide important information about the evolutionary significance of enzyme polymorphisms. It may add insight about the impact of climate change on native insects. Finally, it will allow undergraduates to participate in basic research, enhance their educational experience and expand their opportunities for the future