Living at the edge: causes and consequences of individual variation in a changing world

环境条件发生了变化。生物体如何对这种变化做出反应，例如温度或食物供应，可能会对其生存和繁殖(即适合性)产生深远的影响，并影响种群动态。了解生物如何受到环境条件的影响是生物科学中的一个基本问题，也可以帮助物种在人类引起的快速环境变化的压力下保护物种。生态学研究通常使用物种特征平均值来解决上述问题，尽管有证据表明物种内表型特征的差异是适应性进化变化的原材料。在一个种群内，个体通常表现出一致的行为差异(“个性差异”)，这些行为差异可能与生理、形态和生活史特征一起进化，形成相关特征的“综合症”。环境条件被假设为影响这些综合征的演变，但目前缺乏经验证据。鉴于相关的性状进化可能也会影响个体的适合度，以及种群或群落的动态，它可能会对关键的进化和生态过程产生深远的影响。需要在自然生境中进行实验性的多性状研究，以测试种内性状变异和跨环境条件下的性状协方差(性状‘综合症’)的原因和后果，以促进我们对环境条件如何塑造个体变异的理解。这样的研究还将使人们能够更准确地预测人类引发的环境变化如何影响人口和物种。我们将进行这样一个实验性的、多性状的研究。这是可能的，因为我们已经确定了一种非常适合研究的有机体，一种不会飞的森林甲虫，它对环境条件的变化有直接的反应，而且扩散能力有限，这使我们能够在严格的实验中解决我们的假设。我们将测试我们的模式物种的个体是否在他们的特征值(表达特征的强度)以及不同环境条件下行为、生理和形态特征之间的协变性方面存在系统性差异。我们将评估这种分化的潜在机制和适合性后果。我们将测试特征差异是否可以预测个体在不同环境条件下的生存和繁殖，包括环境变化，并将评估由此对种群动态造成的后果。我们将研究森林核心和边缘的个体(边缘是环境条件改变的栖息地边界，通常是通过土地利用的变化)，并将确定塑造个体差异的主要环境变量。我们将进行易位和圈养相结合的实验，以使个体暴露在不同的环境条件下，并测量他们对变化的反应，以及由此产生的健康后果。我们的项目将对种内性状变异和协方差的原因和后果，以及它们与环境条件的相互作用提供新的见解。我们的研究将是第一批使用跨越世代内和世代之间的行为、形态、新陈代谢和适合度的多性状协方差方法来解决物种内变异对环境条件变化的短期和长期反应的作用的研究之一。我们将首次通过实验评估种内性状变异和协方差在自然条件下昆虫物种对边缘效应的个体反应和适应结果中的作用。我们的项目还将深入了解人类引起的环境变化对昆虫和更广泛的动物的潜在影响的机制。

Environmental conditions change. How an organism reacts to such changes, for instance in temperature or food availability, can have profound consequences for its survival and reproduction (i.e. its fitness) and influence population dynamics. Understanding how organisms are influenced by environmental conditions is a fundamental issue in the biosciences, and can also help conserve species under pressure of rapid human-induced environmental change.Ecological studies typically address the above problem using species trait averages despite evidence that within-species variation in phenotypic traits is the raw material for adaptive evolutionary change. Within a population, individuals often show consistent behavioural differences ('personality differences') and these may evolve together with physiological, morphological and life-history traits forming 'syndromes' of correlated traits. Environmental conditions are hypothesised to affect the evolution of these syndromes but empirical evidence is lacking currently. Given that correlated trait evolution probably also affects individual fitness, as well as population or community dynamics, it is likely to have profound implications for key evolutionary and ecological processes. Experimental, multi-trait studies in natural habitats that test the causes and consequences of within-species trait variation and trait covariances (trait 'syndromes') across environmental conditions are needed to advance our understanding of how environmental conditions shape individual variation. Such studies will also enable more accurate predictions about how human-induced environmental change influences populations and species. We will conduct such an experimental, multi-trait study. This is possible because we have identified a well-suited study organism, a flightless forest-dwelling ground beetle with immediate response to changes in environmental conditions and limited dispersal power, allowing us to address our hypotheses in rigorous experiments.We will test whether individuals of our model species vary systematically in their trait values (strength at which a trait is expressed) and covariances among behavioural, physiological and morphological traits across environmental conditions. We will assess the underlying mechanisms and fitness consequences of this differentiation. We will test whether trait differences predict individual survival and reproduction in different environmental conditions, including environmental change, and will assess resulting consequences on population dynamics. We will study individuals at forest cores and edges (edges are habitat boundaries with altered environmental conditions, usually through land use change), and will identify the main environmental variables that shape individual differences. We will conduct a combination of translocation and enclosure experiments to expose individuals to different environmental conditions and measure their reaction to change, and the fitness consequences thereof. Our project will provide novel insights into causes and consequences of within-species trait variation and covariances, and their interplay with environmental conditions. Our study will be one of the first to address the role of within-species variation on short- and longer-term responses to changed environmental conditions using a multi-trait, covariance approach spanning behaviour, morphology, metabolism and fitness within and across generations. For the first time, we will assess experimentally the role of within-species trait variation and covariances on individuals' response to and fitness consequences of edge effects in an insect species under natural conditions. Our project will also provide insight into the mechanisms underlying effects of human-induced environmental change on insects in particular, and animals more generally.