RUI: Quantifying larval behavior to reconcile genetic connectivity with biophysical model predictions

扩散是连接生态和进化过程的关键生活史特征。浮游幼虫的迁移影响底栖动物的定植成功和种群的持久性，并影响种群的遗传细分、局部适应和物种形成。然而，最近的研究质疑了长期以来的假设，即远洋幼虫的持续时间(PLD)决定了幼虫平流的距离。这具有实际意义，因为用于预测海洋保护区之间交换的海洋学模型通常使用PLD作为关键的幼虫参数。研究人员对加勒比海腹足类的数据显示，基因突变与模型预测不一致，结构水平与幼虫寿命不一致，这突显了新理论的必要性。知识优势：这项研究将整合分子和幼虫生态学，在系统发育框架内测试扩散和幼虫持续时间之间的联系，并确定基于个体的模型(IBM)是否准确预测加勒比海珊瑚礁生态系统的交换。PI将收集多个基因座的遗传数据，并量化14种相关的、生态上相似的海参幼虫的行为，这些物种在0-30天内具有PLD。PI预测，幼虫的行为解释了为什么一些物种相对于它们的PLD来说分散不足或过度分散；这项工作将揭示生物物理耦合模型预测沿海无脊椎动物连通性所需的关键参数。该提案将解决3个相互关联的目标：(1)从线粒体DNA和核标记估计遗传连通性是否一致，并与模型预测一致？线粒体和核基因座的数据将用于测试线粒体DNA的选择，估计基因流动的速度和分化时间，并评估每个物种内的连接水平。模型预测的交换矩阵将与遗传相似矩阵进行比较，以测试基因流动是否在预测的地方发生中断。(2)遗传连通性与PLD是否相关？更广泛地说，PI将测试幼虫时期决定扩散的假设，使用系统发育框架中的比较方法来修正物种之间的亲缘关系的影响。PI将使用分子系统学和多基因座遗传数据，将性状进化模型与贝叶斯马尔科夫链蒙特卡罗(MCMC)方法进行比较，以确定基因流与PLD是否相关。(3)幼虫行为能解释PLD较长物种的遗传结构吗？在这项研究中选择的焦点物种中，至少有两个物种分散不足，尽管有30天的PLD，但遗传上孤立的DEME。相反，至少有一个短PLD物种在加勒比海大片地区没有遗传结构。PI将建立在过去量化幼虫行为的工作基础上，以询问幼虫游泳中特定物种的差异是否有助于局部保留，使物种偏离预期的连接模式。PI还将测试具有预适应能力的幼虫是否会像鱼类一样，以影响扩散的方式对栖息地提示做出反应。这项工作将通过机械地解释连接性的中断来协调生活史理论、海洋学模型和遗传学；结果将加深我们对幼虫行为如何决定种群分化速度的理解。更广泛的影响：学生培训是这项提案的主要主题，该提案的基础是一家为拉美裔服务的机构。资金将支持来自代表性不足的种族群体的本科生和理科硕士学生(目前9名研究生中有5名是拉丁裔或黑人)。克鲁格将与研究生和本科生合著者发表论文，并努力将学生安排在博士项目中；在上一个资助期，7篇论文有学生合著者，两名少数族裔学生被博士项目录取。通过已建立的伙伴关系，PI将在资助研究经验的第一年接待一名地区高中教师和三名学生。通过COSEE-WEST的持续推广将使PI领导的小组能够利用海洋生态学和进化论的例子增加K-12科学教师的教学知识。公众宣传活动将包括在当地NPR附属广播电台(KPCC)每两个月播出一次，并通过旨在扩大科学和技术劳动力多样性的计划，在K-12和社区大学一级举办讲座。

Dispersal is a critical life-history trait linking ecological and evolutionary processes. Transport of planktonic larvae affects colonization success and population persistence for benthic animals, and influences genetic subdivision of populations, local adaptation, and speciation. However, recent studies question the long-held assumption that pelagic larval duration (PLD) determines how far larvae are advected. This has applied significance, as oceanographic models used to predict exchange among marine protected areas often use PLD as the key larval parameter. The investigators' data for Caribbean gastropods show genetic breaks that are not congruent with model predictions, and levels of structure that are inconsistent with larval lifespan, highlighting a need for new theory. Intellectual merits: This research will integrate molecular and larval ecology to test the link between dispersal and larval duration in a phylogenetic framework, and determine whether Individual Based Models (IBMs) accurately predict exchange for Caribbean reef ecosystems. The PI will collect multi-locus genetic data and quantify larval behavior for 14 related, ecologically similar species of sea slugs with PLDs from 0-30 days. The PI predicts that larval behavior explains why some species are under- or over-dispersed relative to their PLD; this work will reveal key parameters needed for biophysical-coupling models to predict connectivity for coastal invertebrates. The proposal will address 3 inter-related objectives: (1) Are genetic connectivity estimates from mtDNA and nuclear markers congruent, and consistent with model predictions? Data for mitochondrial and nuclear loci will be used to test for selection on mtDNA, estimate rates of gene flow and times of divergence, and assess levels of connectivity within each species. Matrices of model-predicted exchange will be compared with genetic similarity matrices to test whether breaks in gene flow occur where predicted. (2) Are genetic connectivity and PLD correlated? More broadly, the PI will test the assumption that larval period determines dispersal, using comparative methods in a phylogenetic framework to correct for effects of relatedness among species. The PI will compare models of trait evolution with Bayesian Markov chain Monte Carlo (MCMC) methods to determine if gene flow is correlated or uncorrelated with PLD, using a molecular phylogeny and multi-locus genetic data. (3) Does larval behavior explain genetic structure in species with long PLD? At least two of the focal species selected for this study are under-dispersed, with genetically isolated demes despite a 30-day PLD. Conversely, at least one short-PLD species has no genetic structure over large regions of the Caribbean. The PI will build on past work quantifying larval behavior to ask if species-specific differences in larval swimming facilitate local retention, making species deviate from expected connectivity patterns. The PI will also test whether pre-competent larvae respond to habitat cues in a way that influences dispersal, as occurs in fish. This work will reconcile life-history theory, oceanographic models, and genetics by mechanistically explaining breaks in connectivity; the results will deepen our understanding of how larval behavior can determine the pace of divergence among populations. Broader impacts: Student training is a major thrust of this proposal, based at a Hispanic-serving institution. Funding will support undergraduate and M.S. students from under-represented ethnic groups (5 of 9 current research students are Latino or black). Krug will publish with graduate and undergraduate student co-authors, and work to place students in Ph.D. programs; in the last funding period, 7 papers had student co-authors and two minority students were accepted into Ph.D. programs. Through established partnerships, the PI will host one area high school teacher and 3 students in the first year of funding for research experiences. Continued outreach through COSEE-west will allow the PI-led group to increase content knowledge for K-12 science teachers using examples from marine ecology and evolution. Public outreach will include bimonthly segments on the local NPR affiliate radio station (KPCC), and lectures at the K-12 and community college level through programs aimed to broaden diversity in the science and technology workforce.