Collaborative research: Variation in life history and connectivity as drivers of pathogen-host dynamics and genetic structure in a trans-hemispheric pathosystem

海洋无脊椎动物使用一系列的策略来生存，移动，并在不同的动态环境条件下繁殖。该项目调查这些策略的交叉点，以及它们如何促进蓝蟹和致病病毒沿着北美和南美大西洋沿岸的持续存在。这种蟹-病毒系统的广泛分布使其可用于研究宿主-病原体相互作用。蓝蟹可以降低它们的活动水平，并在寒冷的气候中诱导冬季休眠，但目前还不清楚这如何改变病原体的进展和传播。相反，热带蓝蟹的全年生长和繁殖可能会被较高的病原体丰度和活动所抵消。该项目将结合实地和实验室研究，揭示螃蟹的生活史和病原体动态如何在其范围的极端情况下相互作用和适应。基因测序、螃蟹运动跟踪和海洋学模型将用于了解螃蟹疾病动态在温带和热带纬度之间的变化。蓝蟹是一种具有生态和经济重要性的物种，本项目产生的知识将有助于提供管理指导，以支持可持续渔业。将通过伙伴关系和讲习班向商业和手工收割者宣传避免和限制疾病的最佳做法。来自代表性不足群体的当地高中和本科生将通过各种正式和非正式的教育计划参与。公众宣传将通过与谢德水族馆的博物馆合作伙伴关系来实施，并将包括培训一名科学交流实习生。这个合作项目将结合联合收割机经验性实地和实验室实验，人口基因组学和生物物理建模，以探索纬度驱动的生活史变化和海洋连通性对由蓝蟹，Callinectes sapidus，以及致病病毒CsRV 1。来自热带和温带地区的CsRV 1病毒的毒力以及越冬的影响将通过在高纬度和低纬度之间移植的螃蟹的实验性病毒挑战来研究。感染和毒力对螃蟹运动的影响将在实验室跑道实验的健康和受感染的螃蟹，并在现场部署在温带和热带地区的声学标记的螃蟹。使用数千个全基因组RAD测序标记的螃蟹和病毒的全基因组测序的群体遗传学研究将定义螃蟹和病毒种群在其范围内的遗传连接性，并将调查可能的纬度，海景和生活史驱动的蓝蟹和病毒基因组的变化。这两个人口基因组数据集预计将提供不同的推论和规模的连接，因为CsRV 1病毒基因型只在幼虫期后的螃蟹之间传播，而蓝蟹基因型也移动了一个潜在的长距离分散的幼虫阶段。最后，综合生物物理模型将被用来调查的相对贡献的成年人和幼虫扩散的人口结构的螃蟹和病原体之间的广泛地带的栖息地新英格兰和阿根廷与十年的模拟。一个开源拉格朗日随机模型将估计浮游幼虫运输，空间显式偏相关随机游走模型将估计成人的运动。模型将通过实验获得的运动和行为数据，以及已发表文献中有关螃蟹幼虫和成虫行为以及越冬持续时间的信息。在一系列的情况下，螃蟹的行为受到纬度和病毒感染的影响，统计比较之间的生物物理模型为基础的预测连接和遗传估计的连接。这些分析将促进我们的理解的物理，环境和生物因素，塑造的动力学的青蟹CsRV 1病理系统。

Marine invertebrates use an array of strategies to survive, move, and reproduce across diverse and dynamic environmental conditions. This project investigates the intersection of these strategies and how they facilitate the persistence of blue crabs and a pathogenic virus along the Atlantic coast of North and South America. The widespread distribution of this crab-virus system makes it useful for investigating host-pathogen interactions. Blue crabs can reduce their activity level and induce winter dormancy in colder climates, but it is unclear how this alters progression and transmission of the pathogen. Conversely, year-round growth and reproduction of tropical blue crabs may be offset by higher pathogen abundance and activity. This project will use a combination of field and laboratory studies to reveal how crab life history and pathogen dynamics interact and adapt at the extremes of their range. Genetic sequencing, crab movement tracking and oceanographic models will be used to understand how crab-disease dynamics vary across temperate and tropical latitudes. The blue crab is an ecologically and economically important species and knowledge generated in this project will help provide management guidance to support sustainable fisheries. Best practices to avoid and limit disease will be communicated to commercial and artisanal harvesters through partnerships and workshops. Local high school and undergraduate students from underrepresented groups will be engaged through a variety of formal and informal educational programs. Public outreach will be implemented through a museum partnership with the Shedd Aquarium and will include the training of a science communication intern.This collaborative project will combine empirical field and laboratory experiments, population genomics, and biophysical modeling to explore the consequences of latitude-driven changes in life history and oceanic connectivity on a trans-hemispheric pathosystem comprised of the blue crab, Callinectes sapidus, and the pathogenic virus, CsRV1. The virulence of the CsRV1 virus from tropical and temperate latitudes and the impact of overwintering will be studied by experimental virus challenges of crabs transplanted between high and low latitudes. The impact of infection and virulence on crab movement will be investigated in laboratory raceway experiments of healthy and infected crabs and in the field with acoustically tagged crabs deployed in temperate and tropical locations. Population genetic studies using thousands of genome-wide RAD sequencing markers for crabs and whole-genome sequencing for the virus will define genetic connectivity of crab and virus populations across their range, and will investigate the possible latitudinal, seascape, and life history-driven changes in blue crab and virus genomes. The two population genomic data sets are expected to provide different inferences and scales of connectivity because CsRV1 virus genotypes are transmitted only among post-larval crabs while blue crab genotypes also move by a potentially long-range dispersive larval stage. Finally, integrated biophysical models will be used to investigate the relative contributions of adult and larval dispersal on the population structure of the crab and the pathogen across a broad swath of habitat between New England and Argentina with a decade of simulations. An open-source Lagrangian stochastic model will estimate pelagic larval transport, and spatially explicit biased-correlated random walk models will estimate adult movement. Models will be informed by experimentally-derived movement and behavior data, as well as information on crab larval and adult behavior and overwintering duration available in the published literature. Under a series of scenarios in which crab behavior is affected by latitude and virus infection, statistical comparisons will be made between biophysical model-based predictions of connectivity and genetic estimates of connectivity. These analyses will advance our understanding of the physical, environmental, and biological factors that shape the dynamics of the blue crab CsRV1 pathosystem.