Mutualisms in a warming world—how increased temperatures affect the outcomes of multi-mutualist interactions

In nature, plant species simultaneously interact with many different mutualistic partners. These mutualists may influence one another through direct interference or indirectly by competing for shared reward resources or through alteration of plant traits. Together, these mutualists also may combine to affect plant hosts in ways that may not be predictable based on pairwise interactions. Given that the outcome of mutualistic interactions often depends on environmental conditions, multi-mutualist effects on one another and their plant hosts may be affected by global changes. Here, we grew focal plants under simulated global warming conditions and manipulated the presence of partner mutualists to test how warming affects the outcome of interactions between focal plants and their partners (nitrogen-fixing rhizobia, ant defenders, and pollinators) and interactions among these partner mutualists. We find that warming alters the fitness benefits plants receive from rhizobium resource mutualist..., ,在自然生态系统中，植物物种会同时与多种不同的互利共生伙伴发生互作。这些互利共生生物可通过直接干扰，或是竞争共享的报酬资源、改变植物性状的间接途径，彼此产生影响。综上，这些互利共生生物共同作用时，可能会以基于成对互作无法预判的方式，对宿主植物产生效应。鉴于互利共生互作的结果通常依赖于环境条件，全球变化或可影响多种互利共生生物彼此间的相互作用，以及这些生物对宿主植物的效应。本研究中，我们在模拟全球变暖的条件下培养目标植物，并通过调控互利共生伙伴的存在与否，探究变暖如何影响目标植物与其伙伴（固氮根瘤菌（nitrogen-fixing rhizobia）、防御性蚂蚁（ant defenders）以及传粉者（pollinators））之间的互作结果，以及这些共生伙伴之间的相互作用。我们发现，变暖会改变植物从根瘤菌资源共生伙伴处获得的适合度收益……