Costs of Resistance in a Natural Host-parasite System

我们对寄生虫抗性背后的遗传变异的大小知之甚少，也不知道维持这种变异的机制。这种信息的缺乏限制了我们预测宿主耐药性和寄生虫毒力进化的能力。本研究旨在了解抵抗寄生的遗传变异的来源，从而了解这一关键生态性状的进化潜力。实验将测试在没有寄生的情况下，遗传抗性是否与寄主的适应成本有关。拟采用的动物系统是索诺兰沙漠特有的果蝇-大螯螨协会。该方法将包括在实验室中通过人工选择产生宿主的行为抗性遗传品系，然后在不同水平的环境胁迫下，根据广泛的幼年和成年适应度特征对比抗性和易感品系。研究结果将为实施害虫物种的可持续生物防治提供基础知识，因此具有重要的实用、社会和经济价值。这项工作探讨了经常在全球范围内看到的环境变化如何影响体外寄生节肢动物的寄生水平，其中许多节肢动物是已知的传染性寄生虫病的媒介。因此，这项研究将为野生动物流行病学、保护生物学以及新出现的动物流行病的医学和兽医研究提供信息。

We know very little about the magnitude of genetic variation underlying parasite resistance, or about the mechanisms responsible for the maintenance of this variation. This lack of information limits our ability to predict the evolution of both host resistance and parasite virulence. This research seeks to understand the source of genetic variation underlying resistance against parasitism, and hence the evolutionary potential of this key ecological trait. Experiments will test whether genetic resistance is associated with fitness costs to the host in the absence of parasitism. The animal system to be employed is the Sonoran Desert endemic Drosophila-Macrocheles mite association. The approach will consist of generating behaviorally resistant genetic lines of the host by artificial selection in the laboratory, followed by contrasting resistant versus susceptible lines in terms of a broad spectrum of juvenile and adult fitness traits under variable levels of environmental stress. The results will contribute basic knowledge toward implementing sustainable biological control of pest species, and hence they will be of significant practical, societal and economic value. The work addresses how environmental change, often seen on a global scale, affects levels of parasitism by ectoparasitic arthropods, many of which are known vectors of transmissible parasitic disease. The research will thus inform wildlife epidemiology, conservation biology, and medical and veterinary research into the causes of emerging animal epidemics.