Long-legged fly (Diptera: Dolichopodidae) communities in Ohio agroecosystems and assessing their role as biological control agents in vegetable crops

Biological control is a vital ecosystem service provided by a diverse guild of predators in agroecosystems.  Biodiversity is thought to be linked to ecosystem functioning through more efficient resource capture and niche partitioning.  Understanding the factors that impact the diversity of these predators is therefore important to our understanding of how to enhance biocontrol services.  Long-legged flies (Diptera: Dolichopodidae) are a particularly ubiquitous yet understudied group of insect predators that are common in all habitats in Ohio, including agricultural systems.  Previous studies have shown that these flies are sensitive to environmental changes, at least in natural systems like grasslands and reed marshes.  The goal of this study is to determine how field management and disturbance influences the community assemblage of Dolichopodidae found in agroecosystems.  During the summer of 2013 and 2014, pan trapping was used to sample the dolichopodid community present in produce farms across northeast Ohio.  Sweet corn, summer squash, and unmanaged old fields were sampled.  Over 3,000 flies representing twelve dolichopodid genera were found.  Analysis shows that overall dolichopodid abundance was actually higher in crop habitats than unmanaged habitats, and that the community within each habitat was different.  Currently, a molecular gut content analysis is also being done to reveal the dietary composition of these flies. Identifying which factors are driving the diversity of this family of flies, as well as figuring out what they are eating, will help us understand how to maximize the biological control services being provided.