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Plant biodiversity and consumers are important mediators of energy and carbon fluxes in grasslands, but their effects on within‐season variation of plant biomass production are poorly understood. Here we measure variation in control of plant biomass by consumers and plant diversity throughout the growing season and their impact on plant biomass phenology. To do this, we analysed 5 years of biweekly biomass measures (NDVI) in an experiment manipulating plant species richness and three consumer groups (foliar fungi, soil fungi and arthropods). Positive plant diversity effects on biomass were greatest early in the growing season, whereas the foliar fungicide and insecticide treatments increased biomass most late in the season. Additionally, diverse plots and plots containing foliar fungi reached maximum biomass almost a month earlier than monocultures and plots treated with foliar fungicide, demonstrating the dynamic and interactive roles that biodiversity and consumers play in regulating biomass production through the growing season.

Insect herbivores are relatively specialized. Why this is so is not clear. We examine assumptions about associations between local abundance and dietary specialization using an 18‐year data set of caterpillar–plant interactions in Ecuador. Our data consist of caterpillar–plant associations and include standardized plot‐based samples and general collections of caterpillars, allowing for diet breadth and abundance estimates across spatial scales for 1917 morphospecies. We find that more specialized caterpillars are locally more abundant than generalists, consistent with a key component of the ‘jack of all trades, master of none’ hypothesis. As the diet breadth of species increased, generalists were not as abundant in any one location, but they had broader occupancy across the landscape, which is a pattern that could reflect high plant beta diversity and is consistent with an alternative neutral hypothesis. Our finding that more specialized species can be both rare and common highlights the ecological complexity of specialization.

Explaining large‐scale ordered patterns and their effects on ecosystem functioning is a fundamental and controversial challenge in ecology. Here, we coupled empirical and theoretical approaches to explore how competition and spatial heterogeneity govern the regularity of colony dispersion in fungus‐farming termites. Individuals from different colonies fought fiercely, and inter‐nest distances were greater when nests were large and resources scarce—as expected if competition is strong, large colonies require more resources and foraging area scales with resource availability. Building these principles into a model of inter‐colony competition showed that highly ordered patterns emerged under high resource availability and low resource heterogeneity. Analysis of this dynamical model provided novel insights into the mechanisms that modulate pattern regularity and the emergent effects of these patterns on system‐wide productivity. Our results show how environmental context shapes pattern formation by social‐insect ecosystem engineers, which offers one explanation for the marked variability observed across ecosystems.

Although interspecific competition has long been recognised as a major driver of trait divergence and adaptive evolution, relatively little effort has focused on how it influences the evolution of intraspecific cooperation. Here we identify the mechanism by which the perceived pressure of interspecific competition influences the transition from intraspecific conflict to cooperation in a facultative cooperatively breeding species, the Asian burying beetleNicrophorus nepalensis. We not only found that beetles are more cooperative at carcasses when blowfly maggots have begun to digest the tissue, but that this social cooperation appears to be triggered by a single chemical cue – dimethyl disulfide (DMDS) – emitted from carcasses consumed by blowflies, but not from control carcasses lacking blowflies. Our results provide experimental evidence that interspecific competition promotes the transition from intraspecific conflict to cooperation inN. nepalensisvia a surprisingly simple social chemical cue that is a reliable indicator of resource competition between species.