Butterfly abundance is higher in areas treated for fire ants

Abstract

Red imported fire ants (Solenopsis invicta; fire ants) are an invasive species that prey on arthropods in the southern United States. Researchers examined using fire ants to control agricultural Lepidoptera pests, but minimal research has investigated the effects of fire ants on the broader butterfly community. Three ranches in Texas, USA, with known fire ant occurrence underwent treatment to remove fire ants, creating a treated section and an untreated section for each ranch. We sampled sites using colored pan traps 3 times per sampling period during 2018 and 2019. Over 2 years, we collected 1,262 butterflies across 28 species in pan traps. Average butterfly abundance was higher in treated sites than untreated sites. The majority of species collected were in the family Hesperiidae, followed by the Pieridae family. We found Hesperiidae species more often in blue pan traps and Pieridae species more often in yellow pan traps. Butterfly species that overwinter as immature stages were more abundant in treated sites than in untreated sites, which suggests there could be a connection between fire ant presence and mortality of overwintering immature stages. Our results suggest that fire ants may negatively affect butterfly communities and differentially affect certain species. Additional research is needed to understand the effects of fire ants on butterflies and the overall pollinator community, and the effectiveness of pan traps for surveying Lepidoptera.