TRICOMM: Structure, assembly and evolution of natural tritrophic communities

TRICOMM：自然三营养群落的结构、组装和进化

• 批准号: NE/T000074/1
• 负责人: Karsten Schonrogge
• 金额: $ 8.75万
• 依托单位: UK CENTRE FOR ECOLOGY & HYDROLOGY
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT000074%2F1
• 关键词: TRICOMM; Structure; assembly; evolution; natural

Communities of plants, insect herbivores, and their insect parasitoid enemies provide most of the known species on Earth. These communities include interactions that lead to economic damage, such as pests of crops, and others that benefit human societies, such as biocontrol agents. Despite their importance, we still know little about what determines which species eat, or are eaten by, other species. We know most about links between plants and herbivores, less about herbivores and parasitoids, and less again about patterns over all three levels combined. A key question is the extent to which such three level (tritrophic) species associations are structured from the 'bottom-up' by plant traits, from the 'top-down' by parasitoids, or some combination of these. The 'bottom-up' view regards herbivore-parasitoid interactions as structured by processes happening a trophic level lower, via the effects of plants on herbivores. In contrast, the 'top-down' view sees parasitoid-herbivore interactions as driving the evolution of herbivore defences, and these traits as more important for structuring parasitoid communities than the host plants on which they are found.This project assesses the evidence for these alternative models, and their combinations, using state of the art statistical methods that require three types of data: (i) an interaction matrix, summarising links between species in one trophic level and those in another; (ii) herbivore defence trait data and (iii) complete species-level phylogenies for plants, herbivores and their parasitoids. Finding that plant phylogeny is a strong predictor of both plant-herbivore and herbivore-parasitoid interactions would support the bottom-up view. In contrast, finding that herbivore-parasitoid interactions are strongly predicted by herbivore defensive traits would support a top-down view. First, we will estimate the effects of species identity and traits on plant-herbivore and herbivore-parasitoid interactions, providing the first test of the relative importance of bottom-up versus top-down processes. We will use over 50,000 records of specific plant-herbivore-parasitoid interactions for natural communities comprising trees, gallwasp herbivores, and chalcid parasitoids, sampled from three regional datasets that span the Northern Hemisphere. These communities have evolved independently for long enough to provide largely independent tests of our hypotheses.

植物群落、食草昆虫群落和它们的寄生敌人提供了地球上已知的大多数物种。这些群落包括导致经济损失的相互作用，如作物害虫，以及其他有利于人类社会的相互作用，如生物防治剂。尽管它们很重要，但我们仍然不知道是什么决定了哪些物种吃其他物种，或者被其他物种吃。我们对植物和食草动物之间的联系了解得最多，对食草动物和拟寄生物的联系了解得较少，对这三个层次结合起来的模式了解得更少。一个关键的问题是，这三个层次（三营养）的物种关联在多大程度上是由植物性状的“自下而上”、寄生生物的“自上而下”或它们的某种组合构成的。“自下而上”的观点认为，草食动物与拟寄生虫的相互作用是由营养水平较低的过程构成的，即通过植物对草食动物的影响。相比之下，“自上而下”的观点认为，寄生物与食草动物的相互作用推动了食草动物防御的进化，这些特征对于构建寄生物群落比它们所在的寄主植物更重要。本项目使用最先进的统计方法评估这些替代模型及其组合的证据，这些方法需要三种类型的数据：(i)相互作用矩阵，总结一个营养水平的物种与另一个营养水平的物种之间的联系；（ii）草食动物防御性状数据和（iii）植物、草食动物及其拟寄生物的完整物种水平系统发育。发现植物系统发育是植物-草食动物和草食动物-拟寄生虫相互作用的一个强有力的预测因子，将支持自下而上的观点。相比之下，发现草食动物与拟寄生物的相互作用是由草食动物的防御特征强烈预测的，这将支持自上而下的观点。首先，我们将估计物种身份和性状对植物-食草动物和食草动物-寄生蜂相互作用的影响，为自下而上与自上而下过程的相对重要性提供第一个测试。我们将使用超过50,000条特定植物-草食动物-拟寄生虫相互作用的记录，这些记录来自跨越北半球的三个区域数据集，包括树木，瘿蜂食草动物和胆酸类寄生虫的自然群落。这些群体已经独立进化了足够长的时间，为我们的假设提供了很大程度上独立的测试。