Survey of dragonflies and damselflies in agroecosystems and their role as biocontrol agents

Natural enemies, like predators and parasites, used as biological control agents for insect pests in agroecosystems can greatly reduce pest populations at little cost to the farmer, and are therefore an important consideration for sustainable farm management practices. Understanding dragonflies in the context of biological control is especially important for the Maryland farmer due to the rich community of dragonflies found in the state. Of the 462 species of dragonflies and damselflies found in North America, 182 are found in Maryland. In fact, the states of Virginia, New York, New Jersey, Maryland and Pennsylvania are among the top eight most speciose in the United States. However, there is no known research examining the community composition of dragonflies on farms. The following study was designed to analyze the abundance and richness of dragonfly species across selected crop and non-crop habitats on several Maryland farms. To address this objective, visual encounter surveys were conducted in two or three crops at each of the following four University of Maryland farms in central and western Maryland. During the summer of 2020 and 2021, 20 dragonflies and 6 damselflies were recorded across four farms. Preliminary findings suggest active breeding populations on the farm may increase abundance and species richness of dragonflies in upland crop habitats. Implementing management practices for conservational biological control of dragonflies, wherein farmers encourage populations on the farm by creating and maintaining favorable habitat, is one strategy to increase dragonfly predation in your crops.