Spatial relationships between ants, prey, and border vegetation in a soybean agroecosystem

The resources provided by unmanaged field border vegetation influence the densities of pests and natural enemies in agroecosystems and interactions between them. Implementation of biological control using generalist predators depends, in part, on the extent bordering vegetation alters to the movement and prey tracking tendencies of predators. Ant (Hymenoptera: Formicidae) communities were used in this study because they react quickly to environmental pressures, are long-lived, and provide multiple ecosystem services. Additionally, ant communities have the potential to impact prey items and host plants in positive and negative ways, depending on the species composition of the ant community and the food resources available. Insights into soybean pest and ant interactions are necessary due to the pervasiveness of ant communities in agroecosystems and the lack of information pertaining to the role of ants as biological control agents within row crops.

This study focused on the interactions of ants and potential prey items, particularly soybean pest species, as mediated by field border vegetation. Samples were collected using pitfall trapping, hand sampling, and sweep net sampling from soybean fields in Kentucky. Each sample had a coordinating GPS coordinate used for hot spot analysis, geographically-weighted regression, and SADIE (Spatial Analysis by Distance IndicEs) analysis. These spatial analyses were used as indicators of population clusters and interactions between ant, prey, and edge resources over time and space. These results indicate the extent to which ants cluster and move throughout soybean fields and quantify the directionality of movements that are driven by soybean pests, alternative prey presence and/or border vegetation.