Impacts of invasive ant-hemipteran interaction, edge effects and habitat complexities on the spatial distribution of ants in citrus orchards

Abstract

The Argentine ant, Linepithema humile, is an invasive ant species well established throughout subtropical climates in the United States. The Argentine ant disrupts natural ecosystems by displacing native ant species and associating with phloem-feeding insects, which they protect from natural enemies in exchange for honeydew excreted by the phloem-feeders. Thus, interactions between these ants and phloem-feeders can be an issue of critical importance in agroecosystems. In this study, we aimed to determine whether the presence or absence of another invasive pest, Asian Citrus psyllid (ACP), Diaphorina citri, adjacent habitat types, and edge complexity impact the species richness, activity, and distribution of ants including the Argentine ant within citrus groves in southern California. When ACP were present and edge complexity was higher, ant activity rates were higher, yet we observed a decline in total ant species richness. Surrounding habitat type had no effect on ant activity or total ant species richness. Understanding the spatial patterns of both the Argentine ant and ACP can aid future management practices for controlling both Argentine ants and Asian citrus psyllid populations.