Multigenerational Trophic Responses to Coupled Short- and Long-term Environmental Change

气候变化对生物多样性的负面影响已经在全球范围内显现，破坏了人类社会所依赖的许多自然生态系统服务，如生物虫害控制、农作物授粉以及清洁水和食物的提供。绝大多数调查气候变化对生物多样性影响的实验都采用了间接的“逐步变化”型方法，即在独立的实验种群中同时比较生物对当前环境条件的反应（如成熟时间）和预测的未来条件，条件之间没有逐渐过渡。例如，在一个示例中，实验将记录生物体在20 ℃条件下的行为，同时来自同一物种的其他生物体暴露于25 ℃。它们反应的差异被用作气候变化如何影响生物多样性的证据。然而，这种方法排除了种群在多代人之间适应和进化的潜力，以逐步，定向的环境变化-种群生物学的基本概念。气候变化是逐渐发生的，尽管随着时间的推移而迅速发生，虽然目前的速度比历史变化快，但我们预计在大多数情况下不会看到条件的瞬间急剧变化。这种差异造成了这些实验预测和真实的世界实际发生的事情之间的理解差距。（“宿主”物种）一种害虫物种，其毛虫消耗并破坏世界各地储存的食品（包括小麦等简单谷物，以及饼干和巧克力），还有一只黄蜂（“寄生虫”）通过在蛾的幼虫阶段产卵来攻击并杀死蛾，对多代的长期温度升高做出反应。寄生虫在控制所有陆地和许多水生食物网中的植物和动物种群方面发挥着关键作用，因此了解它们如何应对气候变化为我们提供了适用于世界各地的非常有用的信息。我们将在一个精心集成的计算机模型系统和精心控制的实验室实验中研究这些反应，在这个全球重要的主机寄生虫相互作用。我们将评估这两个物种的关键生物学特征，例如它们作为青少年的时间长度，这对温度高度敏感，如何影响它们的种群规模随时间的变化，以及它们是否可以继续生活在一起，或者至少一个或两个物种灭绝。我们将测试这些反应是否以及如何在2年内逐渐增加1.5或3 ℃的温度下变化，跨越~18个宿主世代。我们将通过调查长期温度趋势周围的短期（每日）波动是否可以掩盖甚至逆转这些种群适应气候变化和多代共存的能力，进一步提高生物现实性。我们将使用数学模型将我们的发现应用于其他物种和气候情景，这些模型基于对数百个其他物种的测量，可从公开数据库中获得。我们的综合工作使我们能够超越事后描述简单的气候变化-生物多样性关系-基于通常出于其他原因收集的数据，更深入地了解天敌系统将如何应对未来的气候变化。这将改变我们对如何预测生态系统将如何应对未来不确定气候变化的理解，大大提高我们对重大全球挑战的理解，如病虫害爆发，入侵物种的威胁和生物多样性的加速丧失。

The negative effects of climate change on biodiversity are already being felt on a global scale, disrupting numerous natural ecosystem services that human societies depend upon, like biological pest control, the pollination of agricultural crops and the provision of clean water and food. The vast majority of experiments investigating the impacts of climate change on biodiversity have used an indirect, "step-change" type approach, where biological responses (like maturation times) to current environmental conditions are compared simultaneously in independent experimental populations, to projected future conditions, with no gradual transition between the conditions. E.g., experiments will record how organisms behave under 20 C conditions at the same time as other organisms from the same species are exposed to 25 C. Differences in their responses are then used as evidence of how climate change will affect biodiversity. However, this approach excludes the potential for populations to adapt and evolve across multiple generations to gradual, directional environmental changes - foundational concepts in population biology. Climate change is happening gradually, albeit rapidly, over time, and while current rates are faster than historical changes, we do not expect to see an instantaneous, dramatic change in conditions in most cases. This disparity creates gaps in understanding between what these experiments predict and what is actually happening in the real world.We will address these fundamental knowledge and evidence gaps by investigating how a moth (the 'Host' species) a pest species whose caterpillars consume and spoil stored food products worldwide (including simple grains like wheat, as well as biscuits and chocolate), and a wasp (the 'Parasitoid') that attacks and kills the moth by laying eggs in the moth's juvenile caterpillar stage, respond to long-term temperature increases across multiple generations. Parasitoids play a key role in controlling plant and animal populations across all land-based, and many aquatic, food webs, therefore understanding how they respond to climate change gives us extremely useful information that is applicable around the world. We will examine these responses in a carefully integrated system of computer models and carefully controlled laboratory experiments, in this globally important Host-Parasitoid interaction. We will assess how key biological features of the two species, such as the length of time they remain as juveniles, which is highly sensitive to temperature, affect how their population sizes change over time and whether they can continue to live together, or at least one or both species go extinct. We will test if and how these responses change under temperatures that gradually increase by either 1.5 or 3 C over 2-years, spanning ~18 Host generations. We will further increase biological realism by investigating whether short-term (daily) fluctuations around the long-term temperature trend can mask, or even reverse, the ability of these populations to adapt to climate change and coexist across multiple generations. We will apply our findings to other species and climate scenarios using mathematical models that are based on measurements from hundreds of other species, available from publicly available databases.Our combined work enables us to move beyond describing simple climate change-biodiversity relationships in hindsight - based on data that was often collected for other reasons, by providing a deeper understanding of precisely how natural-enemy systems will respond to future climate change. This will transform our understanding of how we can predict how ecosystems will respond to future, uncertain climate change, vastly improving our understanding of major global challenges, such as pest and disease outbreaks, threats from invasive species and the accelerating loss of biodiversity.