Ant communities as providers of ecosystem services in no-till cropping systems

Ants are ecosystem engineers, shaping the structure and function of many terrestrial ecosystems. These social insects deliver in natural habitats and some agricultural systems well-documented ecological services, ranging from soil improvement to pest control. Despite their potential benefits, ant communities in northern temperate crop fields remain poorly studied, largely due to historical use of tillage. No-till farming systems, however, create stable habitats that appear to allow ant populations to establish, grow, and influence crop production. We are investigating how ant communities contribute to ecosystem services in no-till fields crops of Pennsylvania. We established a three-year 2x2 factorial experiment at two Pennsylvania research farms, manipulating presence and absence of a cereal rye cover crop and abundance of ants, which we reduced in half of the plots using boiling water. We characterized ant communities through baiting and pitfall trapping and assessed their functional roles using seed-predation trays and sentinel-prey assays with waxworms. First-year results revealed that both sites supported similar ant communities comprising nine species, with significantly higher ant abundance in plots with cover crops. Rates of seed predation on weed species were significantly higher in plots with higher abundance of ants than ant-reduced plots. Sentinel prey assays with waxworms demonstrated that ants consistently inflicted mortality regardless of cover crop presence or ant abundance manipulation. Our findings thus far indicate that ants can provide meaningful ecosystems in no-till systems. To benefit from their activities, farmers would need to commit to integrated pest management and avoiding unnecessary insecticide use.