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

物种在一片土地上的传播速度往往被低估，因为研究人员不承认，由于自然选择，传播和繁殖速度也会有所反应。当有害的入侵物种或稀有的重新引入物种的扩张被低估时，社会影响可能是重大的。这个项目将通过测量物种传播和繁殖力之间的遗传相关性来纠正对物种传播的长期低估。考虑自然选择对范围扩展的影响，将通过提供入侵物种传播的准确估计，大大改善入侵物种的管理。该项目将加强对有前途的年轻研究者的研究和培训。两名本科生将接受实验、计算和数学生态学方面的培训。研究人员将为来自少数民族和经济条件不利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。在范围扩张过程中，个体根据分散能力在空间上进行分类。在前沿的种群是由高度分散的个体控制的，这些个体通过选择性交配。当扩散是可遗传的，空间分选将增加前沿种群的世代扩散，导致进化加速入侵。边缘种群也出现在低同种密度，获得生殖优势。空间选择理论几乎完全建立在模型的基础上。本项目考察了生态现实背景下空间选择的重要性，使用实验室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具有可忽略不计的影响。它将研究扩散和繁殖力之间的遗传相关性如何改变空间选择的预期，使用模拟模型参数化来自普通甲虫的数据。研究人员推测，扩散和繁殖力之间的负相关遗传关系将减轻空间选择的影响，而正相关遗传关系将放大空间选择的影响。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能通过减少入侵前沿的个体数量或减弱入侵边缘的空间分选信号和降低生殖潜力来减缓入侵。随着扩散遗传力的降低，该信号应进一步减弱。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.