Parasites and Communities; Empirical and Theoretical Scaling

寄生虫和群落；

• 批准号: NE/G015236/1
• 负责人: Stuart Bearhop
• 金额: $ 1.63万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG015236%2F1
• 关键词: Parasites; Communities; Empirical; Theoretical; Scaling

Parasites interest ecologists because, by making animals ill, they alter how those animals interact with other species in natural communities. We have studied the parasites of two species of native and invading shrimps and found that parasites alter how often the shrimp of one species eat the other shrimp species (a process called intraguild predation), and the other types of prey that they select to eat. In addition, shrimp may respond to the threat of being eaten by predators (fish) by becoming less active and so potentially less likely to eat other animals. The challenge now is to study the consequences of these effects for the wider community: how parasites and predators influence which species we find in the community and how common they are. We will use lab and field experiments, and mathematics to look at this problem, to: firstly, build up a picture of how parasites and predators affect interactions between two or three species; secondly, examine how these effects alter the relationships between other species in the community. 1. We will examine how parasites affect predation, for example using laboratory experiments to measure the functional response (the relationship between a predator's consumption rate of prey and the density of the prey) for infected shrimp compared with uninfected shrimp in the presence and absence of predator cues. This will help us build mathematical models in which parasites alter their hosts' functional responses so that we can investigate how behaviour modification affects population dynamics (changes in population size over time). 2. We will use stable isotope analysis (which measures chemical variation to tell us about an animal's diet) of natural shrimp populations to see whether parasites cause a shift in host diets. We will also investigate this idea using laboratory experiments. We will build a mathematical model that links together the interactions of parasitism, predation, and intraguild predation, and use this to investigate the population dynamics of the species involved and see whether the parasite-induced changes in functional responses and diet that we expect to find in the shrimp community can change community structure. Our findings will be of interest to other scientists concerned with the impact of parasites on interactions between species, and their impact in the broader community and environment. It will also interest agencies who manage natural habitats, diversity and invasions (Environment Agency; N. Ireland Environment Agency, Department of Agriculture and Rural Affairs, N. Ireland). It is important to study parasites for many reasons. Firstly, as they are often 'hidden' members of the community, and do not often kill their hosts, their effects have been neglected compared to other interactions between species (such as predation and competition). Nevertheless, they can have dramatic impacts on communities, altering the balance between competing species, sometimes allowing two species to coexist where one would go extinct if parasites were not present (this makes the parasite a 'keystone species'). Secondly, parasites are often involved in biological invasions by foreign species into a new environment; in many cases an invading species does more damage because it is not as badly infected by the parasites in that environment, or it introduces new parasites that cause illness/death of the native species. Indeed, in our study system, one of the shrimps is an invading species and we are keen to understand the forces driving its success so that we can better protect the native species. Thirdly, parasites have important public health and economic consequences: emergent diseases (parasites that cross the species boundary to infect a new species) are an increasing threat to human health, domestic animals and wildlife. This project will help to understand these important problems by improving what we know about the effects of parasites in natural communities.

寄生虫感兴趣的生态学家，因为通过使动物生病，它们改变了这些动物与自然社区中其他物种相互作用的方式。我们研究了两种本地和入侵虾的寄生虫，发现寄生虫改变了一种物种的虾多久就会吃掉另一种虾种类（一种称为内部捕食的过程），以及他们选择吃的其他类型的猎物。此外，虾可能会对被掠食者（鱼）食用的威胁做出反应，从而降低了其他动物的活力，因此可能不太可能吃其他动物。现在面临的挑战是研究这些影响对更广泛的社区的后果：寄生虫和捕食者如何影响我们在社区中发现的哪些物种以及它们的普遍性。我们将使用实验室和现场实验以及数学来研究这个问题，以：首先，建立寄生虫和捕食者如何影响两个或三个物种之间的相互作用的图片；其次，检查这些影响如何改变社区中其他物种之间的关系。 1。我们将研究寄生虫如何影响捕食，例如使用实验室实验来测量受感染的虾的功能反应（捕食者的猎物消耗率与猎物的密度之间的关系）与在存在和没有捕食者提示的情况下相比，与未感染的虾相比。这将有助于我们建立数学模型，在这种模型中，寄生虫会改变其宿主的功能响应，以便我们可以研究行为修改如何影响人群动态（随着时间的推移，人口大小的变化）。 2。我们将使用稳定的同位素分析（测量化学变异来告诉我们动物饮食）天然虾种群，以查看寄生虫是否导致宿主饮食的变化。我们还将使用实验室实验调查这个想法。我们将建立一个数学模型，该模型将寄生虫，捕食和内部捕食的相互作用联系在一起，并使用它来研究所涉及物种的种群动态，并查看寄生虫诱导的功能反应变化和我们期望在虾类社区中发现的功能反应和饮食变化。我们的发现将引起其他与寄生虫对物种相互作用及其在更广泛的社区和环境中的影响的影响的科学家。它还将使管理自然栖息地，多样性和入侵的机构感兴趣（环境局； N. Ireland环境局，农业和农村事务部，北爱尔兰）。出于许多原因，研究寄生虫很重要。首先，由于他们经常是社区中“隐藏”的成员，并且不经常杀死他们的宿主，因此与物种之间的其他相互作用（例如捕食和竞争）相比，它们的影响被忽略了。然而，它们可能会对社区产生巨大的影响，改变竞争物种之间的平衡，有时允许两个物种共存，如果不存在寄生虫，则可以灭绝一个物种（这使寄生虫成为“基石物种”）。其次，寄生虫通常参与外国物种的生物学入侵，进入新环境。在许多情况下，入侵物种会造成更大的损害，因为它在该环境中的寄生虫不那么严重，或者引入了引起本地物种疾病/死亡的新寄生虫。确实，在我们的研究系统中，其中一个虾是一种入侵物种，我们渴望了解推动其成功的力量，以便我们可以更好地保护本地物种。第三，寄生虫具有重要的公共卫生和经济后果：新兴疾病（穿越物种边界以感染新物种的寄生虫）对人类健康，家畜和野生动植物的威胁日益加剧。该项目将通过改善我们对寄生虫在自然社区的影响来帮助理解这些重要问题。