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

物种在一片土地上传播的速度经常被低估，因为研究人员不承认自然选择会对物种的扩散和繁殖率做出反应。当一个有害的入侵物种或罕见的重新引入物种的扩张被低估时，可能会产生重大的社会影响。这个项目将通过测量物种扩散和繁殖力之间的遗传相关性来纠正长期低估的物种传播。考虑到自然选择对范围扩大的影响，通过提供对入侵物种传播的准确估计，将显著改善对入侵物种的管理。该项目将改善对一位有前途的年轻研究员的研究和培训。两名本科生将接受实验、计算和数学生态学方面的培训。研究人员将为德克萨斯州少数民族和经济困难背景的中学生开发课程，教授生物入侵的原因和后果，强调快速进化的重要性。在范围扩大的过程中，个体根据扩散能力在空间上进行分类。处于领先边缘的种群主要由高度分散的个体组成，它们进行分类交配。当扩散是可遗传的时，空间排序将在前沿种群的世代中增加扩散，导致进化加速的入侵。边缘种群也出现在同种密度较低的地方，从而获得繁殖优势。空间选择的理论几乎完全基于模型。这个项目考察了生态现实背景下空间选择的重要性，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大中发挥重要作用，以及何时或是否可能产生微不足道的影响。它将使用用一种常见甲虫的数据参数化的模拟模型，研究分散性和繁殖力之间的遗传相关性如何改变空间选择的预期。研究人员假设，分散性和繁殖力之间的负遗传相关性将缓解空间选择的影响，而正遗传相关性将放大这种影响。第二项研究将研究随机性如何与空间选择相互作用来影响入侵速度。人口随机性可能通过减少入侵前沿的个体数量或减弱入侵边缘的空间排序信号和减少入侵边缘的生殖潜力来减缓入侵。随着扩散遗传力的降低，这一信号应该进一步减弱。研究人员将结合这两项研究来阐明在什么情况下，空间选择作为入侵动态的驱动因素或多或少是重要的。

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.