DISSERTATION RESEARCH: Do trait correlations and demographic stochasticity alter the dynamics of evolutionarily-accelerated invasions?

物种在景观中传播的速度往往被低估，因为研究人员不承认传播和繁殖率可以因自然选择而做出反应。当一种有害的入侵物种或一种罕见的重新引入物种的扩张被低估时，社会影响可能是重大的。该项目将通过测量扩散和繁殖力之间的遗传相关性来纠正对物种扩散的长期低估。考虑到自然选择对范围扩张的影响，通过提供对入侵物种传播的准确估计，将大大改善对入侵物种的管理。该项目将改善研究和培训有前途的年轻调查员。两名本科生将接受实验，计算和数学生态学的培训。研究人员将为来自少数民族和经济弱势背景的德克萨斯州中学生开发课程，教授生物入侵的原因和后果，强调快速进化的重要性。处于领先地位的种群由高度分散的个体主导，这些个体相互交配。当扩散是可遗传的时，空间排序将增加前沿种群的扩散，从而导致进化加速的入侵。边缘种群也发生在低同种密度，获得生殖优势。空间选择理论几乎完全基于模型。该项目研究了空间选择在生态现实环境中的重要性，使用基于实验室的实验和计算机模拟模型来了解空间选择何时可能在范围扩展中发挥重要作用，以及何时或是否可能产生可忽略的影响。它将研究如何传播和繁殖力之间的遗传相关性修改期望的空间选择，使用模拟模型参数化的数据从一个共同的甲虫。研究人员假设，扩散和繁殖力之间的负遗传相关性将减轻空间选择的影响，而正遗传相关性将放大这种影响。第二项研究将探讨随机性如何与空间选择相互作用，影响入侵速度。人口统计学随机性可以通过减少入侵前沿的个体数量或通过削弱空间分选信号和降低入侵边缘的生殖潜力来减缓入侵。随着扩散遗传力的降低，这种信号应进一步降低。研究人员将整合这两项研究，以阐明空间选择作为入侵动力学驱动因素或多或少重要的条件。

The speed at which species spread across a landscape is often under-predicted because researchers do not acknowledge that dispersal and reproductive rates can respond due to natural selection. When the expansion of a harmful invasive species or a rare re-introduced species is under-predicted, societal implications can be significant. This project will correct chronic under-prediction of species' spread by measuring genetic correlations between dispersal and fecundity. Accounting for the effects of natural selection on range expansion will significantly improve management of invasive species by providing accurate estimates of their spread. The project will improve the research and training of a promising young investigator. Two undergraduate students will be trained in experimental, computational, and mathematical ecology. The researchers will develop lessons for Texas middle-school students from minority and economically-disadvantaged backgrounds to teach the causes and consequences of biological invasions, highlighting the importance of rapid evolution.During range expansion, individuals become spatially sorted by dispersal ability. Populations at the leading edge are dominated by highly dispersive individuals that mate assortatively. Spatial sorting will increase dispersal in leading edge populations over generations when dispersal is heritable, resulting in evolutionarily-accelerated invasions. Edge populations also occur at low conspecific densities, gaining a reproductive advantage. The theory of spatial selection is based almost entirely on models. This project examines the importance of spatial selection in ecologically realistic contexts, using laboratory-based experiments and computer simulation models to understand when spatial selection is likely to play an important role in range expansion, and when, or if, it is likely to have negligible effects. It will examine how genetic correlations between dispersal and fecundity modify expectations for spatial selection, using simulation models parameterized with data from a common beetle. The researchers hypothesize that negative genetic correlations between dispersal and fecundity will mitigate the effects of spatial selection, while a positive genetic correlation will amplify the effects. The second study will examine how stochasticity interacts with spatial selection to affect invasion speed. Demographic stochasticity may slow invasions by reducing the number of individuals at the leading edge of the invasion or by weakening the signal of spatial sorting and reducing reproductive potential at the invasion edge. This signal should be further reduced as dispersal heritability decreases. The researchers will integrate these two studies to elucidate conditions under which spatial selection is more or less important as a driver of invasion dynamics.