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.

我在东北太平洋的长期岩石潮间带现场，使我的研究项目能够解决有关反捕食特征进化的新问题，以应对捕食风险的时空变化。我们的研究系统包括四种蜗牛属的蜗牛物种，它们的壳厚度和扩散潜力各不相同，以及一种本土捕食者，紫岸蟹。 1993年，我在两个暴露在波浪中的海岸上建造了螃蟹庇护所，以增加当地紫岸蟹的密度。这导致了对邻近蜗牛种群的成熟尺寸和壳厚度的选择。 与此同时，气候变化正在导致非本地捕食蟹的活动范围向极地扩展，从而影响了对本地猎物物种的有限捕食。在此背景下，我计划在未来五年实现三个短期目标： 1. 确定遗传和塑料对有限体型捕食风险增加的反应。 我们将确定自 27 年前通过安装螃蟹庇护所建立捕食梯度以来，我们现场的反捕食者特征是如何进化的，以及这些变化在高分散性和低分散性蜗牛物种之间有何不同。可塑性将通过在共同环境中培养田间收集的蜗牛卵（有或没有螃蟹废水）来评估。我们还将研究 L. subrotundata 的形态变化如何与行为适应（即躲避捕食者）相关。 2. 发现针对捕食者的遗传和可塑性适应的遗传结构。 我们将使用全基因组测序来发现 DNA 标记，用于估计蜗牛的传播。我们还将对从螃蟹收容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特征相关的基因组区域。 3. 由于捕食者的活动范围扩大到加拿大而引起的猎物灭绝风险的模型变化。 在两次大型厄尔尼诺事件期间，我的混凝土庇护所被非本地岸蟹入侵。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张口有限的掠食者对不同大小级别猎物的消耗率。我们将预测具有不同扩散能力的猎物物种南部界限的变化，以应对捕食者向北范围的扩展。 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，该实验增进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捕食者向极地入侵后的持久性。拟议的研究将极大地推进我的长期目标，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。