Collaborative Research: Physiological and Genetic Responses to Winter in a Willow Leaf Beetle

在内华达山脉，像许多高海拔环境一样，积雪每年都非常多变。许多高海拔动物在雪下过冬，雪为它们抵御极端温度提供了缓冲。许多独特的、具有生态重要性的动物生活在山区环境中，因此了解和预测积雪覆盖的年度差异对其种群数量的影响至关重要，但到目前为止，我们对雪如何影响昆虫和其他动物的生存和繁殖的了解有限。该项目计划在实验室和自然环境中研究高海拔甲虫对积雪变化的生理和遗传反应，以了解雪如何改变冬季和随后的夏季繁殖成功。这项工作将在加州大学伯克利分校和两所主要的本科生机构之间建立合作伙伴关系。主要是本科院校的本科生将与伯克利分校的研究人员合作，伯克利分校的博士生将指导来自各种背景和经验的本科生。因此，这两组学生都将接触到不同教育机构的文化，并有机会接触到他们通常网络之外的专业联系人。根据该项目为K-12学生开发的课程模块将用于帮助他们了解生物在下雪气候中面临的挑战，该模块将通过加州大学伯克利分校的网站分发给K-12教师。对于高海拔动物来说，夏天是获得能量的时候，而冬季节能是关键，因为资源稀缺，动物依赖能量储备。为了抵御冬季寒冷，高海拔昆虫利用能量储存来合成代谢性昂贵的冷冻保护剂。这可能会在耐寒性和节能之间产生一种权衡。雪缓冲了温度波动，降低了寒冷死亡率和对寒冷耐寒的需求。然而，由于雪下的温度高于无雪、裸露的栖息地，因此与雪下生活相关的总体能源需求可能会增加。由于能量的取舍，冬季积雪和气温的年际波动将改变越冬生物的选择压力，并可能显著影响夏季的生长和繁殖。中心假设是，积雪的变化改变了对耐寒和节能的选择性压力，影响了越冬个体的生理表现和幸存者的遗传组成。研究人员进一步假设，由于耐寒的能量成本，冬季能量储备会耗尽冬季能量储备，从而影响未来的繁殖。这项研究将：1)测量雪的变化如何改变高海拔甲虫冬季相关遗传变异的选择性梯度，并分离冬季选择性梯度的原因驱动因素。2)对寒冷和能量压力如何相互作用在冬季和随后的夏季形成生理表现进行预测性和量化的理解。3)通过询问单一或复合应激源如何改变能量储备和低温保护剂的反应规范，揭示寒冷和能量应激之间相互作用的潜在机制。

In the Sierra Nevada mountain ranges, like many high altitude environments, snow cover is extremely variable from year to year. Many high altitude animals survive through winter underneath snow that buffers them from extremes of temperature. Many unique and ecologically important animals live in mountainous environments, making it vital to understand and predict impacts of annual differences in snow cover on their population abundances, but as yet we have limited understanding of how snow impacts survival and reproduction of insects and other animals. This project proposes to study physiological and genetic responses to variation in snow cover in a high altitude beetle in the laboratory and the natural environment to understand how snow alters reproductive success during the winter and subsequent summer. This work will develop a partnership between UC-Berkeley and two Primarily Undergraduate Institutions. Undergraduates at the Primarily Undergraduate Institutions will work with researchers from Berkeley, and Berkeley PhD students will supervise undergraduates from a wide variety of backgrounds and experiences. Thus both groups of students will be exposed to the culture of different educational institutions and will have access to professional contacts outside their usual network. A curriculum module developed from the project for K-12 students will be used to contribute towards their understanding of challenges that organisms face in snowy climates, and this module will be distributed to K-12 teachers through a UC Berkeley-based website.For high altitude animals, summer is a time of energy gain, while energy conservation is key during winter because resources are scarce and animals rely on energy stores. To resist winter cold, high altitude insects use energy stores to synthesize metabolically expensive cryoprotectants. This may generate a trade-off between cold hardiness and energy conservation. Snow buffers thermal fluctuations, decreasing cold mortality and need for cold hardiness. However, since temperatures are greater beneath snow than in a snow-free, exposed habitat, there may be increased overall energy demand associated with living under snow. Due to the energetic trade-off, inter-annual fluctuations in winter snowpack and air temperature will alter selective pressures on overwintering organisms, and may significantly affect growth and reproduction in summer. The central hypothesis is that variation in snow cover alters selective pressures on cold hardiness and energy conservation, influencing physiological performance of overwintering individuals and genetic composition of survivors. The investigators further hypothesize that cold hardiness trades off against future reproduction by depleting winter energy reserves due to energetic costs of cold hardiness. The research will: 1) Measure how variation in snow alters selective gradients on winter-relevant genetic variation in a high altitude beetle, and isolate causal drivers of winter selective gradients. 2) Gain a predictive and quantitative understanding of how cold and energy stressors interact to shape physiological performance during winter and the subsequent summer. 3) Uncover mechanisms underlying interactions between cold and energy stress by asking how single or combined stressors alter reaction norms for energy reserves and cryoprotectants.