Ecology of fear: ecological and evolutionary consequences of non-consumptive effects of parasites

恐惧生态学：寄生虫非消耗性影响的生态和进化后果

• 批准号: RGPIN-2020-03910
• 负责人: Luong, Lien
• 金额: $ 2.4万
• 依托单位: University of Alberta
• 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=716719
• 关键词: Ecology; fear; ecological; evolutionary; consequences

Parasites can cause significant harm to their hosts, hence potential hosts should try to avoid coming into contact with infectious stages of the parasite. Hosts can avoid exposure to infection by avoiding infective stages, associated cues, infected individuals, or alter their habitat use to avoid encountering parasite. These indirect non-consumptive effects are known as the “ecology of fear”. The proposed project will experimentally answer the following questions: 1) Are the non-consumptive effects (NCEs) of parasites context and state-dependent? When an organism is exposed to parasites, it may change it's activity, rate of respiration, feeding behaviour, space use, and/or time allocation to various activities in order to avoid infection. Exactly how individuals respond to a perceived threat will depend on the environmental conditions and it's own internal condition (age, sex, energetic state, etc.). We will investigate the context-dependent nature of the NCE and whether the effects carry over across developmental stages and reproductive states. 2) Are there trait-mediated indirect effects of parasites? Parasites can also modify the behaviour of the host in ways that influence how it interacts with non-host species in the community (e.g., competitors, predators). The perception of infection risk could cause an increase in activity, which could in turn put an individual at greater risk of detection by predators. We will investigate the potential for conflict between anti-parasite and anti-predator defenses. 3) Are the NCEs of parasites on host metabolism context and state-dependent? The “fight or flight” response to a natural enemy often involves increased activity and respiration. We will measure the metabolic rate of flies exposed to parasites (without contact) over the short- and long-term. The metabolic rate of an organism is known to vary with sex, age, reproductive status, and external conditions (e.g., temperature, crowding). In addition to examining the state-dependent nature of the metabolic changes, measuring the reaction norm of the mean CO2 production under different conditions, including duration of exposure, types of parasite cues, and density of conspecifics. We will also measure associated changes in fly feeding behaviour. 4) What are the evolutionary consequences of NCE? Even as evidence for the ecology of fear and its fitness consequences mounts, the long-term evolutionary consequences of non-consumptive effects remains poorly understood. We will employ "laboratory natural selection" in which the environment of a laboratory-maintained population is altered (i.e., exposed to parasites) and the survivors become the parents of the next generation. The treatment populations will be compared to unaltered control populations after 10 generations. While multiple responses are possible, we will focus on changes in metabolism, feeding behaviour, body mass, anti-parasite behaviors (grooming, activity), and resistance to infection.

寄生虫会对宿主造成重大伤害，因此潜在的宿主应尽量避免接触寄生虫的感染阶段。寄生虫可以通过避免感染阶段、相关线索、感染个体或改变其栖息地使用以避免遇到寄生虫来避免暴露于感染。这些间接的非消耗性影响被称为“恐惧生态”。拟议的项目将通过实验回答以下问题： 1)寄生虫的非消耗性效应（NCE）是否依赖于环境和状态？当生物体暴露于寄生虫时，它可能会改变其活动，呼吸速率，进食行为，空间使用和/或各种活动的时间分配，以避免感染。个人如何应对感知到的威胁取决于环境条件和自身的内部条件（年龄，性别，精力充沛的状态等）。我们将研究NCE的背景依赖性，以及其影响是否会跨越发育阶段和生殖状态。 2)寄生虫是否存在性状介导的间接效应？寄生虫还可以改变宿主的行为，影响宿主如何与群落中的非宿主物种相互作用（例如，竞争者，掠夺者）。对感染风险的感知可能会导致活动增加，这反过来又会使个体面临更大的被捕食者发现的风险。我们将研究抗寄生虫和抗捕食者防御之间的潜在冲突。 3)寄生虫对宿主代谢的非竞争性效应是否依赖于环境和状态？对天敌的“战或逃”反应通常包括增加活动和呼吸。我们将测量短期和长期暴露于寄生虫（无接触）的苍蝇的代谢率。已知生物体的代谢率随性别、年龄、生殖状态和外部条件（例如，温度、拥挤）。除了检查代谢变化的状态依赖性，测量不同条件下平均CO2产生的反应规范，包括暴露持续时间，寄生虫线索类型和同种密度。我们还将测量苍蝇喂养行为的相关变化。 4)NCE的进化后果是什么？尽管恐惧的生态学及其适应性后果的证据越来越多，但人们对非消耗性效应的长期进化后果仍然知之甚少。我们将采用“实验室自然选择”，即改变实验室维持的种群的环境（即，暴露于寄生虫），幸存者成为下一代的父母。10代后，将处理群体与未改变的对照群体进行比较。虽然多种反应是可能的，但我们将重点关注代谢，摄食行为，体重，抗寄生虫行为（梳理，活动）和对感染的抵抗力的变化。