Evolution of clines in poorly-dispersing prey populations in response to spatial variation in selection by gape-limited predators

分散性差的猎物种群中的进化对张口限制捕食者选择的空间变化的响应

• 批准号: RGPIN-2020-05150
• 负责人: Boulding, Elizabeth
• 金额: $ 2.04万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717394
• 关键词: Evolution; clines; poorly; dispersing; prey

My long-term rocky intertidal field sites in the Northeast Pacific, allows my research program to address novel questions about the evolution of antipredation traits in response to spatial and temporal changes in the risk of predation. Our study system includes four snail species in the genus Littorina that vary in shell thickness and dispersal potential, and an indigenous predator, the purple shore crab. In 1993, I constructed crab shelters on two wave-exposed shores to increase the local density of the purple shore crab. This has caused selection for size at maturity and shell thickness in adjacent snail populations. At the same time, climate change is causing poleward range extensions of a non-native predator crab that is impacting size-limited predation on indigenous prey species. In this context, I plan to address three short-term objectives over the next 5 years: 1. Determine genetic and plastic responses to increased risk of size-limited predation. We will determine how antipredator traits have evolved at our field site since we established a predation gradient by installing crab shelters 27 years ago, and how these changes differ between high and low dispersing snail species. Plasticity will be assessed by culturing field-collected snail eggs with and without crab effluent in a common environment. We will also examine how morphological changes may be related to behavioural adaptations (i.e., predator avoidance) in L. subrotundata. 2. Discover genetic architecture of genetic and plastic adaptations to predators. We will use whole genome sequencing to discover DNA markers which will be used to estimate snail dispersal. We will also genotype snails collected from different distances from crab shelters and then search for genome regions associated with antipredator traits. 3. Model changes in prey extinction risk caused by range extensions of predators into Canada. During two large El Nio events, my concrete shelters were invaded by the nonindigenous lined shore crab. To model the risk of extinction of native prey species, we will conduct laboratory experiments to determine consumption rates from this crab and other gape-limited predators on different size-classes of prey. We will forecast changes in the southern limits of prey species with differing dispersal abilities in response to northern range extensions of predators. What is novel about the proposed work is that it is based on a long-term field predator-addition experiment that has advanced our understanding of genetic adaptation at the whole organism level. Our expertise in modelling, parameter estimation, and genomics, will quantify how the dispersal and evolutionary potential of prey populations affects their persistence after poleward invasions of predators resulting from climate change. The proposed research will significantly advance my long-term goal of determining when high dispersal potential or rapid evolutionary adaptation can prevent populations from extinction.

我的长期岩石潮间带场网站在东北太平洋，使我的研究计划，以解决新的问题，在空间和时间变化的捕食风险的抗捕食性状的演变。我们的研究系统包括四种蜗牛属Littorina不同的外壳厚度和扩散潜力，和土著捕食者，紫色海岸蟹。 1993年，我在两个暴露在海浪中的海岸建造了螃蟹庇护所，以增加紫色海岸蟹的密度。这导致了邻近蜗牛种群对成熟时的大小和壳厚的选择。 与此同时，气候变化正在导致非本地捕食者螃蟹的极地范围扩展，这正在影响对本地猎物物种的大小有限的捕食。在这方面，我计划在未来五年内实现三个短期目标： 1.确定遗传和塑料反应，以增加风险的大小有限的捕食。 我们将确定如何antipredator性状已经在我们的现场网站，因为我们建立了捕食梯度安装蟹庇护所27年前，以及这些变化之间的差异高，低分散蜗牛物种。可塑性将通过培养现场收集的蜗牛卵与螃蟹的污水和没有在一个共同的环境进行评估。我们还将研究形态变化如何与行为适应有关（即，捕食者回避）。近圆形的 2.发现遗传和塑料适应捕食者的遗传结构。 我们将使用全基因组测序来发现DNA标记，这些标记将用于估计蜗牛的扩散。我们还将对从螃蟹庇护所不同距离收集的蜗牛进行基因分型，然后寻找与反捕食者性状相关的基因组区域。 3.捕食者范围扩展到加拿大引起的猎物灭绝风险的模型变化。 在两次大的厄尔尼诺事件中，我的混凝土庇护所被非土著的海岸蟹入侵。为了模拟本地猎物物种灭绝的风险，我们将进行实验室实验，以确定这种螃蟹和其他间隙有限的捕食者对不同大小的猎物的消费率。我们将预测的变化，在南部限制的猎物物种不同的传播能力，以应对北方范围扩展的捕食者。 这项工作的新颖之处在于，它是基于一项长期的野外捕食实验，该实验提高了我们对整个生物体水平上遗传适应的理解。我们在建模，参数估计和基因组学方面的专业知识，将量化猎物种群的扩散和进化潜力如何影响它们在气候变化导致的捕食者向极地入侵后的持久性。这项研究将大大推进我的长期目标，即确定何时高扩散潜力或快速进化适应可以防止种群灭绝。