Collaborative Research: Plasticity, Selection, and Divergence in Stream Fishes of the Hawaiian Islands

合作研究：夏威夷群岛溪流鱼类的可塑性、选择和分化

• 批准号: 0817794
• 负责人: Richard Blob
• 金额: $ 27.6万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-01 至 2012-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0817794&HistoricalAwards=false
• 关键词: Collaborative; Research; Plasticity; Selection; Divergence

Differences in adaptive traits often correlate with environmental variation, but can arise from two different sources: differentiation of genes, or phenotypic plasticity, the capacity of a single genotype to encode multiple phenotypes. Distinguishing between these mechanisms is a central challenge in evolutionary biology. Hawaiian stream fishes provide a superb system for directly measuring the evolutionary mechanisms leading to changes in form and function in response to environmental variation. The five fish species native to Hawaiian streams are all amphidromous: larvae hatch upstream but are quickly swept to the ocean, where they develop up to six months before returning to freshwater. For three species, returns require climbs of vertical waterfalls tens of meters tall before reaching adult habitats. However, adult habitats differ strongly between the oldest (Kaua'i) and youngest (Hawai'i) islands. Hawaiian waterfalls are close to shore, placing a premium on climbing ability to escape non-climbing predators; in contrast, Kauaian falls are far inland, placing a premium on predator evasion as fish migrate upstream. Biomechanical models predict these contrasting demands will select for divergent body shapes. This project is a collaboration among a biomechanist, a population geneticist, a morphologist, and an aquatic ecologist to test the hypothesis that natural selection has promoted adaptive divergence in stream gobies in response to differing environmental challenges between Hawai'i and Kaua'i through a combination of genetic differentiation and adaptive phenotypic plasticity. A series of complementary studies on the climbing goby Sicyopterus stimpsoni and the non-climbing goby Stenogobius hawaiiensis will be conducted. Goals are to: (1) evaluate morphological divergence in juveniles and adults from several stream subpopulations on Hawai'i and Kaua'i, and test for correlations with environmental differences in streams; (2) evaluate the strength of selection imposed on gobies by climbing and predation, and test for performance differences between populations from Hawai'i and Kaua'i; (3) evaluate neutral genetic divergence in juvenile and adult S. stimpsoni and S. hawaiiensis from several streams on Hawai'i and Kaua'i, and test for differential patterns of gene flow in these species; (4) conduct common garden predator exposure experiments to evaluate levels of genetically based local adaptation and environmentally induced phenotypic plasticity among island subpopulations. This work will provide a model for research on the interactive mechanisms promoting the evolution of organismal form and function in response to environment. This project involves collaboration of research-focused (Clemson) and teaching-centered (St. Cloud State) institutions, and will promote integrative training in genetics, morphology, and functional biology for both undergraduate and graduate students, including local interns with the Hawai'i Division of Aquatic Resources (DAR). Cooperation with the DAR will inform water management decisions so that detrimental impacts of human stream use can be limited in Hawai'i, helping to protect these endemic freshwater fishes.

适应性性状的差异通常与环境变化相关，但可能来自两个不同的来源：基因分化或表型可塑性，即单一基因型编码多种表型的能力。区分这些机制是进化生物学的核心挑战。夏威夷溪流鱼类提供了一个极好的系统，可以直接测量导致形式和功能变化的进化机制，以应对环境变化。夏威夷溪流中的五种原生鱼类都是无游性的：幼虫在上游孵化，但很快就会被冲到海洋中，在那里发育长达六个月，然后返回淡水。对于三个物种来说，回归需要在到达成年栖息地之前爬上数十米高的垂直瀑布。然而，最古老的岛屿（考艾岛）和最年轻的岛屿（夏威夷岛）之间的成年人栖息地有很大的不同。夏威夷的瀑布靠近海岸，这使得瀑布的攀爬能力更强，可以避开不攀爬的捕食者;相比之下，考艾岛的福尔斯位于内陆，当鱼类向上游迁移时，瀑布更容易避开捕食者。生物力学模型预测，这些不同的需求将选择不同的体型。该项目是一个生物力学家，种群遗传学家，形态学家和水生生态学家之间的合作，以测试假设，自然选择促进了适应性分歧流虾虎鱼在夏威夷和考爱岛之间的不同环境挑战，通过遗传分化和适应性表型可塑性的组合。本研究将对爬网虾虎鱼和非爬网虾虎鱼进行一系列的互补研究。目标是：（1）评估夏威夷和考爱岛几个溪流亚群的幼鱼和成鱼的形态差异，并检验溪流中环境差异的相关性;（2）评估通过攀爬和捕食对虾虎鱼施加的选择强度，并检验夏威夷和考爱岛种群之间的性能差异;（3）评估夏威夷和考爱岛虾虎鱼幼鱼和成鱼的中性遗传差异。stimpsoni和S.（4）进行常见的花园捕食者暴露实验，以评估基于遗传的局部适应水平和岛屿亚群之间环境诱导的表型可塑性。这项工作将为研究促进生物体形式和功能响应环境的相互作用机制提供一个模型。该项目涉及以研究为重点的（克莱姆森）和以教学为中心的（圣克劳德州）机构的合作，并将促进本科生和研究生在遗传学，形态学和功能生物学方面的综合培训，包括夏威夷水产资源部（DAR）的当地实习生。与DAR的合作将为水资源管理决策提供信息，以便在夏威夷限制人类使用河流的有害影响，帮助保护这些特有的淡水鱼类。