Identification of native and invasive fire ants in southern New Mexico using DNA fingerprinting and lateral flow immunoassay techniques

The red imported fire ant, Solenopsis invicta, is an invasive species introduced into Alabama in 1918. S. invicta has since spread across the Southern U.S., displacing native fire ant species from the Solenopsis geminata species complex, like Solenopsis xyloni. First detection of S. invicta in Doña Ana County, New Mexico occurred in 1998 resulting in a federal quarantine since the reported detection. Since taxonomic uncertainty exists between S. xyloni and S. invicta due to their extremely similar morphology, additional analytical tools are required to create diagnostic certainty. Here we report the results of a survey where Cytochrome oxidase I and Wingless sequences were used for species identification of individual ants from 97 different fire ant populations collected from Dona Ana County, NM. In addition, lateral flow immunoassay tests were performed on all ant samples included in the study. All of the fire ants were determined by both lateral flow immunoassays and DNA sequencing to be native southwestern fire ant species and no instances of S. invicta were found. Potential reasons for S. invicta failing to establish and displace native species in Dona Ana County, NM are discussed.