Reproduction in a changing world: how do rising temperatures affect reproductive capacity?

气候变化对生物多样性构成了重大威胁，我们刚刚开始看到它对物种分布、持久性和物候学的影响的初步迹象。在外温动物中，物种的行为、生理和分布受到温度的深刻影响，预计这类动物特别容易受到气温上升的影响。虽然已经研究了气温上升的生态和物候后果，但我们在很大程度上没有调查对生殖的影响。众所周知，温度会严重影响雄性可育性，但这种温度诱导的不育症的生态和进化后果很少被考虑。然而，男性的生育力往往受到不成比例的影响，不育发生在动物身体功能受损的温度以下。因此，在身体受到高温影响之前，个体可能会遭受生殖障碍。通过这项研究计划，我想纠正我们知识中的这一重要差距，并调查a)适应不同环境的物种对温度诱导不育的敏感性有何不同；b)这种温度诱导不育的潜在分子机制是什么；c)雄性和雌性是否受到类似的影响；d)这种敏感性是否能够进化，使雄性即使在温度上升的情况下也能保持生育能力。我将通过使用三种果蝇在不同温度下测量雄性和雌性生殖成功的实验来实现这些目标。我将结合不同温度下男性受精成功的表型分析和蛋白质组学方法来阐明潜在的分子基础。我将进一步进行一项实验进化研究，将果蝇暴露在不同的温度条件下，并测量由此产生的表型和遗传变化。这项研究计划将提供对雄性和雌性繁殖力随温度变化的估计，并调查这种现象的表型表达和遗传基础。估计男性和女性生殖力的潜在损害，对于更好地了解对个人健康和人口水平的长期影响至关重要。这些数据不仅会告诉我们一个基本的生物过程对温度上升的脆弱性，而且还会告诉我们，随着温度的升高，男性生育力的下降是否会威胁到物种的持久性。

Climate change poses a major threat to biodiversity and we are just beginning to see the first signs of its impact on species distribution, persistence and phenology. In ectotherms behaviour, physiology and distribution of species are profoundly affected by temperature and this group of animals is expected to be particularly vulnerable to rising temperatures. While ecological and phenological consequences of rising temperatures have been studied, have we largely failed to investigate the impact on reproduction. It is well known that particularly male fertility can be severely affected by temperature, however the ecological and evolutionary consequences of this temperature induced sterility have rarely been considered. Often though male fertility is disproportionately affected and sterility occurs at temperatures below those impairing somatic function in animals. Thus individuals can suffer from impaired reproduction before they are physically affected by high temperatures. With this research program I want to rectify this important gap in our knowledge and investigate a) how species adapted to different environments differ in their sensitivity of temperature-induced infertility; b) what are the underlying molecular mechanisms of this temperature-induced infertility; c) are males and females similarly affected and d) whether this sensitivity can evolve such that males can maintain fertility even under rising temperatures. I will achieve these goals by performing experiments using three Drosophila species measuring male and female reproductive success at different temperatures. I will combine phenotypic assays of male fertilisation success at different temperatures with a proteomics approach to elucidate the underlying molecular basis. I will further conduct an experimental evolution study exposing Drosophila melanogaster to different thermal regimes and measure the resulting phenotypic and genetic changes. This research program will provide an estimate of temperature dependent changes in male and female fecundity and investigate the phenotypic expression and genetic basis of this phenomenon. Estimating potential impairments in male and female fecundity is vital for a better understanding of long-term effects on individual fitness and at the population level. These data will not only inform us of the vulnerability of a basic biological process to rising temperatures but also whether temperature dependent reduction in male fertility might threaten species persistence.