Comparison of coccinellid community assemblages between agricultural grass-dominated habitats and natural tallgrass prairies

Coccinellid communities are increasing in species richness with the intentional or unintentional introduction of non-native species, while simultaneously declining in species evenness as the abundance of native species decreases, potentially due to predation by or competition with non-native species. The destruction of natural habitats may exacerbate this trend, since invasion success is often tied to environmental degradation. Our objective was to determine whether coccinellid community composition varies between simplified agricultural tall fescue habitats and diverse natural tallgrass prairie habitats, either remnant or restored. We predicted that natural tallgrass prairie habitats would resist the establishment of non-native coccinellid species and therefore promote the abundance and species richness of native coccinellid species. We compared coccinellid communities between natural and agricultural habitats by collecting adult coccinellids from five remnant tallgrass prairies, five restored prairies, and four fescue fields throughout Missouri using yellow sticky traps on a monthly basis throughout the summer of 2010. Contrary to our prediction, we found that total coccinellid abundance and species richness was greater in agricultural habitats than in natural habitats. This result was driven by the greater abundance and species richness of native lady beetles in tall fescue than tallgrass prairie habitats. These preliminary data do not support the hypothesis that natural tallgrass prairie habitats provide a refuge for native coccinellid species by resisting the invasion of non-native species. However, habitat characteristics, perhaps resource availability or food web interactions, do appear to play a role in mediating the interaction between native and non-native species.