Understanding aquatic Herbivore performance under changing regimes of thermal and nutritional Variance (HerbiVar)

最近的研究预测，气候极端事件的频率、强度和持续时间将发生重大变化，这将体现在温度空间和时间频率分布的较高统计时刻(例如，方差和偏度)。由于外温热反应规范的非线性，预计热方差区域的变化对外温热反应的影响甚至比平均温度变化更大。外温带可利用的食物资源(在能量、生化和矿物组成方面)的平均特性和可能的时空变化也将受到气候变化的影响。温度决定了外温体中能量的获取和消耗，但也决定了它们对特定营养物质的结构要求。因此，必须同时考虑温度和营养的伴随变化，以试图了解外温虫种群正在发生的和未来的变化。到目前为止，所有关于食物-温度相互作用的研究都集中在它们的平均值的变化上。这个项目超越了平均值，目的是提高我们对食物和温度的更高统计时刻如何相互作用的理解，以及影响外温体适合性的方法。以大型水生生物(Daphnia Magna)作为模式生物，第一个目标将是开发食物数量、食物质量(根据必需脂肪酸、胆固醇和磷)以及温度变化和协方差对关键健康成分(死亡率、发育、繁殖)的影响的理论模型。基于这些模型，将有可能产生清晰的理论驱动的假说，这些假说可以进行实验测试。这项工作将架起营养和热生态生理学的桥梁，并将它们置于时空异质性的背景下。预计它将对外星人在持续的温度和资源变化过程中面临的挑战提供强有力的见解。

Recent studies predict important changes to the frequency, intensity and duration of climate extremes which will manifest in the higher statistical moments (e.g. variance and skewenness) of temperature spatial and temporal frequency distributions. Because of the non-linearities of ectotherm thermal reaction norms, changes in the thermal variance regimes are expected to impact ectotherms even more than mean temperature changes. The mean properties and likely the spatio-temporal variance of the food resources (in terms of energy, biochemical and mineral composition) available to the ectotherms will also be affected by climate change. Temperature dictates the energy acquisition and expenditure in ectotherms but also their structural requirements for specific nutrients. Hence, the concomitant changes of temperature and nutrition have to be considered simultaneously in any attempt to understand ongoing and future changes of ectotherm populations. To date, all research on food-temperature interactions focused on changes in their mean values. This project goes beyond mean values and aims to improve our understanding of how higher statistical moments of food and temperature interact with each other and with the means to affect the fitness of ectotherms. Using an aquatic ectotherm (Daphnia magna) as model organism, the first objective will be to develop theoretical models of the effects of food quantity, food quality (in terms of essential fatty-acids, cholesterol and phosphorous) and temperature variances and covariances on critical fitness components (mortality, development, reproduction). Based on these models, it will be possible to generate clear theory-driven hypotheses that can be experimentally tested. This work will bridge nutritional and thermal ecophysiology and place them within the context of spatio-temporal heterogeneity. It is anticipated that it will yield powerful insights into the challenges ectotherms are facing in the course of ongoing temperature and resource changes.