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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740415
• 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 Niño 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.

我在东北太平洋的长期岩石潮间带场地，使我的研究计划能够解决关于反捕食特征的进化，以响应被捕食风险的时空变化的新问题。我们的研究系统包括四种壳厚和扩散潜力不同的Littorina属蜗牛，以及一种本土捕食者紫岸蟹。1993年，我在两个暴露在海浪中的海岸上建造了蟹笼，以增加当地紫岸蟹的密度。这导致了邻近蜗牛种群对成熟时大小和壳厚的选择。与此同时，气候变化正在导致一种非本地捕食蟹的范围向极地扩展，这影响了本地猎物物种的大小限制捕食。在此背景下，我计划在未来5年实现三个短期目标：确定遗传和塑性反应增加的风险大小有限的捕食。我们将确定自27年前通过设置螃蟹庇护所建立捕食梯度以来，我们的野外站点的反捕食特征是如何演变的，以及这些变化在高分散和低分散的蜗牛物种之间是如何不同的。将通过在普通环境中使用和不使用螃蟹排出物培养实地收集的蜗牛卵来评估其可塑性。我们还将研究如何形态变化可能与L. subrotundata的行为适应（即，捕食者回避）有关。2. 发现对捕食者的遗传和塑料适应的遗传结构。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。我们还将从距离螃蟹庇护所不同距离处收集蜗牛进行基因分型，然后寻找与抗捕食者性状相关的基因组区域。3. 捕食者向加拿大扩展活动范围导致的猎物灭绝风险模型变化。在两次大型El Niño活动期间，我的混凝土庇护所遭到了外来滨蟹的入侵。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缝隙有限的捕食者对不同大小类别猎物的消耗率。我们将预测具有不同扩散能力的猎物物种的南部边界的变化，以响应捕食者的北部范围扩展。这项工作的新颖之处在于，它是基于一项长期的野外捕食者添加实验，该实验提高了我们对整个生物体水平上的遗传适应的理解。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极地捕食者入侵后的持久性。拟议的研究将大大推进我的长期目标，即确定高扩散潜力或快速进化适应何时可以防止种群灭绝。