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：