Highlights•In some instances, insects can be large direct inputs of biomass to the detrital
pool.•Insects and other small invertebrates transform biomass and alter decomposition
rates.•Predatory arthropods can affect trophic cascades in 'brown'food webs.•Predatory
arthropods can create an environment of risk that ultimately alters ecosystem
functions.Insects and other small invertebrates are ubiquitous components of all terrestrial
and freshwater food webs, but their cumulative biomass is small relative to plants and …