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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744785
• 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.

寄生虫可对其宿主造成重大伤害，因此潜在宿主应尽量避免接触寄生虫的感染阶段。宿主可以通过避开感染阶段、相关线索、受感染个体或改变栖息地以避免接触寄生虫来避免接触感染。这些间接的非消费效应被称为“恐惧生态”。该项目将通过实验回答以下问题：1)寄生虫的非消耗效应（NCEs）是否依赖于环境和状态？当一个有机体暴露于寄生虫时，它可能会改变它的活动、呼吸速率、摄食行为、空间使用和/或时间分配到各种活动中，以避免感染。确切地说，个体对感知到的威胁的反应取决于环境条件和自身的内部条件（年龄、性别、精力状态等）。我们将研究NCE的环境依赖性质，以及这种影响是否会在发育阶段和生殖状态中延续。2)寄生虫是否存在性状介导的间接效应？寄生虫还可以改变寄主的行为，从而影响寄主如何与群落中的非寄主物种（如竞争对手、捕食者）相互作用。对感染风险的感知可能会导致活动的增加，这反过来又可能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)寄生虫的NCEs是否依赖于宿主的代谢环境和状态？对天敌的“战斗或逃跑”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（如温度、拥挤程度）而变化。除了检查代谢变化的状态依赖性外，还测量了不同条件下平均二氧化碳产量的反应规范，包括暴露时间、寄生虫线索类型和同种生物的密度。我们还将测量苍蝇摄食行为的相关变化。4) NCE的进化结果是什么？即使有越来越多的证据表明恐惧的生态学及其对健康的影响，但人们对非消耗性影响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，将处理种群与未改变的对照种群进行比较。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。