Molecular and Evolutionary Mechanisms Underlying Desiccation Resistance Across Drosophila Species

了解当前物种如何适应极端环境，如沙漠，可以帮助确定物种如何进化以应对环境变化。由于气候迅速变化，环境变得越来越温暖和干燥，生物必须适应这些变化，才能在这些新条件下生存和繁衍。昆虫利用身体表面的脂质层来防止水分流失和抵御干燥压力。本研究将探讨昆虫种类间这种脂质层的耐干燥性与化学性质之间的关系。此外，本研究将以一种生活在沙漠中的昆虫为模型，探讨昆虫如何进化出非常高的干旱性的生理和遗传机制。由于这种脂质层的成分在许多昆虫物种中也起着信息素的作用，因此这些成分的进化变化可能导致交配成功率的变化。该研究结果将为确定环境适应如何导致昆虫物种之间交配行为和生殖隔离的变化提供经验证据。该项目将利用现有基础设施，通过研讨会、视频和科学博览会的参与，向学生、教师和公众推广STEM教学、培训和学习，并扩大代表性不足的少数民族的充分参与。适应不同的环境和栖息地是物种长期生存的关键。减少水分流失对适应不同陆地环境的生物很重要。在果蝇和其他陆生昆虫中，这种防止水分流失的能力至关重要。以往的研究表明，角质层水分损失是昆虫水分损失的主要原因，并假设角质层碳氢化合物（CHC）含量的差异是介种和荒漠物种之间抗旱性差异的原因。然而，不同CHC成分与干旱之间的具体联系尚未确定，这些赋予高干旱性的CHC成分进化的遗传机制尚未阐明。本研究将探讨昆虫中CHCs的进化如何影响其干旱抗性，并阐明沙漠物种Drosophila mojavensis中CHCs进化的遗传机制和进化限制。由于CHCs是双重性状，还具有其他功能，如配偶识别，因此控制这些CHCs在这些双重角色中的进化的限制因素尚不清楚。本项目还将研究CHCs在抗旱性中的功能如何影响配偶识别。总的来说，这个项目的长期目标是阐明分子和进化机制，使物种能够承受水分流失并保持水分平衡，因为我们的星球在未来几十年变得更加温暖和干旱。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding how current species adapt to extreme environments such as the desert can help determine how the species could evolve in response to environmental changes. As environments get warmer and drier due to rapid climate change, organisms must adapt to these changes to survive and thrive in these new conditions. Insects use a lipid layer on their body surface to prevent water loss and withstand desiccation stress. The proposed study will investigate the association between desiccation resistance and chemical properties of this lipid layer across insect species. Furthermore, this study will use a desert-dwelling insect species as a model to investigate the physiological and genetic mechanisms underlying how insects can evolve very high desiccation resistance. Since components of this lipid layer also function as pheromones in many insect species, evolutionary changes in these components can lead to changes in mating successes. Results from this study will provide empirical evidence in determining how environmental adaptation can lead to changes in mating behaviors and reproductive isolation between insect species. The project will use existing infrastructure to promote STEM teaching, training, and learning to students, teachers, and the public through workshops, videos, and science fair participation, as well as broaden full participation of underrepresented minorities.Adaptation to different environments and habitats is key to long-term species persistence. Decreasing water loss is important for organisms adapting to different terrestrial environments. In Drosophila fruit flies and other terrestrial insects, this ability to prevent water loss is crucial. Previous studies suggested that cuticular water loss accounts for the majority of water loss in insects and hypothesized that differences in cuticular hydrocarbon (CHC) content account for differences in desiccation resistance between mesic and desert species. However, the specific association between different CHC components and desiccation has not been established, and the genetic mechanisms underlying the evolution of these CHC components that confer high desiccation resistance have not been elucidated. This proposed study will investigate how evolution of CHCs in insects affects desiccation resistance and elucidates the genetic mechanisms and evolutionary constraints that govern their evolution in a desert species, Drosophila mojavensis. As CHCs are dual traits that also have other functions such as mate recognition, the constraints that govern the evolution of these CHCs in these dual roles are not well understood. This project will also investigate how the functions of CHCs in desiccation resistance may affect mate recognition. Collectively, the long-term goal of this project is to elucidate the molecular and evolutionary mechanisms that enable species to withstand water loss and maintain water balance as our planet gets warmer and more arid in the next few decades.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.