Edge effects on insects depend on life history traits: a global meta-analysis

Some species are more affected than others by edge effects resultant from habitat loss and fragmentation, generally due to human activities. As these specific responses depend on biophysical and behavioral traits of organisms, it is expected that the occurrence of species with particular traits will vary between fragment edges and interiors. Edges are also known to often harbor many invasive species. We performed a meta-analysis of the responses of insect species with different life history traits to anthropogenic edges, focusing on the species’ behavioral characteristics and whether they are considered invasive or not. We systematically searched the Web of Science database for papers on this subject published until May 2018. We examined response ratios for 712 comparisons of anthropogenic edge effects on insects. As expected, the responses differed according to the traits evaluated. Soil-foraging and social insects were negatively affected by anthropogenic edges. Conversely, flying and invasive species were favored by edges. Our analyses suggest that edges, by differently affecting different insect groups, have an important role in structuring local insect communities. Finally, the importance of functional traits in studies of edge effects must be highlighted.