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Immunity at the population level: understanding the effects of environmental change

人口层面的免疫力：了解环境变化的影响

基本信息

批准号：
NE/J023787/1
负责人：
Robert Knell
金额：
$ 51.35万
依托单位：
Queen Mary University of London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ023787%2F1
关键词：
Immunity population level understanding effects

项目摘要

One consequence of environmental change that is especially hard to predict is the way that infectious diseases will respond to a different climate. This is important not only for people but also for most animals and plants which are frequently victims of disease in both natural and managed ecosystems. If we want to understand the effects of environmental change on disease we need to know how immune systems change when the environment changes, especially when we are thinking about diseases of ectotherms (cold-blooded organisms): these are strongly affected by environmental variables like temperature in many ways, including how much they invest in immunity. Knowing about how immunity in cold-blooded animals will respond to climate change is important for many reasons. The vast majority of animals are ectotherms and the potential for disruption of ecosystems and loss of biodiversity from new infectious diseases is huge. Pest animals, or rare animals that we want to conserve, might become more or less affected by disease and therefore increase or decrease in number, and from a human point of view the immune responses of insects that carry diseases such as malaria can determine whether they are able to carry these diseases and transmit them to people: the immune systems of mosquitos, for example, act against any malaria parasites that the mosquito is carrying.Previous research into how ectotherm immunity reacts to the environment has shown that the picture is complicated. If carry out a lab experiment to measure the effect of changing (for example) the quality of food available, this will certainly tell us something about how immunity might change if food availability changes, but whether this information will be useful is questionable: what we have recently found is that the way that immunity responds to food quality, or temperature, or how crowded the population is, itself depends on other variables: increasing the temperature, for example, can lead to either increases or decreases in immunity depending on how crowded the animals are. When the environment changes it is inevitable that more than one such factor will change at the same time. Increasing temperature, for example, will lead to changes in rainfall and changes in the abundance of many animal species, meaning that the amount of food available and the degree of crowding will change as well as the temperature. In fact, the web of interactions between these environmental factors makes it essentially impossible to predict how ectotherm immunity is likely to change in real-world systems: you'd need to know so many details about the system (temperature, food availability, humidity, population density, etc.) that you'd never be able to make useful predictions.The proposed research will sidestep this problem by monitoring immune investment in a model ectotherm species (a moth called Plodia interpunctella) in experimental laboratory ecosystems that will be kept at one of three temperatures and provided with two different qualities of food. These ecosystems will be run for around twenty generations of the moth, and we will monitor the insects' immune responses and their ability to fight off bacterial infection throughout this period. This approach will tell us how immunity changes in these animals in these simple laboratory ecosystems as a consequence of environmental change without the need to measure every single detail of the system (although we will measure some important details like population density). We will also measure whether the moths evolve during this period, which is a potentially important way that animals might mitigate the effects of environmental change. The results of this research will give us a very detailed data set telling us not only how immunity and disease resistance in these animals changes with the environment, but also how fast they evolve in response to changes in the environment.

环境变化的一个后果是特别难以预测的是传染病将如何应对不同的气候。这不仅对人很重要，而且对大多数动物和植物也很重要，因为它们在自然生态系统和管理的生态系统中都经常成为疾病的受害者。如果我们想了解环境变化对疾病的影响，我们需要知道当环境变化时，免疫系统如何变化，特别是当我们考虑外温动物（冷血生物）的疾病时：这些疾病在许多方面受到环境变量的强烈影响，如温度，包括它们在免疫方面投入了多少。了解冷血动物的免疫力如何应对气候变化是很重要的，原因有很多。绝大多数动物是外温动物，新的传染病对生态系统造成破坏和生物多样性丧失的可能性是巨大的。我们想要保护的有害动物或稀有动物可能会或多或少地受到疾病的影响，因此数量会增加或减少，从人类的角度来看，携带疟疾等疾病的昆虫的免疫反应可以决定它们是否能够携带这些疾病并将其传播给人类：例如，蚊子的免疫系统可以抵抗蚊子携带的任何疟疾寄生虫。2先前关于外温免疫如何对环境作出反应的研究表明，情况是复杂的。如果进行一个实验室实验来测量改变的效果，（例如）可用食物的质量，这肯定会告诉我们如果食物供应发生变化，免疫力可能会如何变化，但这些信息是否有用值得怀疑：我们最近发现免疫力对食物质量、温度或人口拥挤程度的反应方式本身取决于其他变量：例如，根据动物的拥挤程度，增加温度可能导致免疫力的增加或减少。当环境发生变化时，不可避免地会有不止一个这样的因素同时发生变化。例如，温度升高将导致降雨量的变化和许多动物物种丰度的变化，这意味着可获得的食物量和拥挤程度将与温度一样发生变化。事实上，这些环境因素之间的相互作用网络使得基本上不可能预测在现实世界的系统中如何改变外温免疫力：你需要知道关于系统的许多细节（温度，食物供应，湿度，人口密度等）。这项研究将通过监测实验室生态系统中的一种模式外温动物物种（一种名为Plodia interpunctella的蛾）的免疫投资来回避这个问题，该生态系统将保持在三种温度之一，并提供两种不同质量的食物。这些生态系统将运行大约20代的蛾，我们将监测昆虫的免疫反应和他们的能力，以抵御细菌感染在整个期间。这种方法将告诉我们，在这些简单的实验室生态系统中，这些动物的免疫力如何随着环境变化而变化，而不需要测量系统的每一个细节（尽管我们将测量一些重要的细节，如人口密度）。我们还将测量飞蛾是否在这一时期进化，这是动物可能减轻环境变化影响的一种潜在的重要方式。这项研究的结果将为我们提供一个非常详细的数据集，不仅告诉我们这些动物的免疫力和抗病能力如何随着环境的变化而变化，而且还告诉我们它们响应环境变化的速度有多快。