D3464: Analyzing spatial and temporal distribution of hymenopteran parasitoids within agricultural drainage ditches and adjacent cropland

Farms in areas with naturally high water tables often utilize artificially created drainage ditches to manage the level of water present. These drainage ditches naturally provide a source of non-crop vegetation adjacent to farms, which can potentially aid populations of natural enemies by providing habitats and food sources. Parasitoid wasps are prolific natural enemies in agroecosystems, with both native and imported species providing biological control against a variety of agricultural pests. The vegetation in and around agricultural drainage ditches can potentially provide pollen and additional hosts for parasitoid wasp populations, aiding in the process of biological control. To better understand the relationship between agricultural drainage ditches and the parasitoid wasp populations of farms, we used sticky traps to collect and identify specimens at five different farms during the summer months of 2021 and 2022 to family level. We analyze how the populations of parasitoid wasps vary across different months and at different proximities relative to agricultural ditches and discuss the implications for conservation biological control. Understanding when and why parasitoid wasp populations move between agricultural ditches and crops can support the development of ditch management practices enabling farms to benefit from a greater abundance of natural enemies.