Invasive fire ant species
The red imported fire ant, Solenopsis invicta, is an invasive species in the southern United States with profound economic impacts. This species has a sting that inflicts pain and can induce allergic reactions. Moreover, its colonies form at high densities, which can interfere with landscaping and crop production. In the fire ant S. invicta, two social forms exist in close proximity: one form has colonies with only one reproductive queen (monogyne) and one form has colonies with multiple reproductive queens (polygyne). Monogyne and polygyne fire ants are differentiated by a large inversion on a “social” chromosome. This inverted region contains hundreds of genes, but is referred to as a “supergene” because it is inherited as a single unit and does not exchange genetic material with the noninverted form of the social chromosome. Supergenes have been implicated in the origin and maintenance of alternative phenotypes in a growing number of diverse animal taxa. Two UGA entomologists have been conducting joint lab meetings over the past three years, and collaboration between the two labs is resulting in a detailed investigation of the gene regulatory consequences of variation in the chromosomal inversion that underlies S. invicta social polymorphism by profiling gene expression levels and chromatin structure. Investigating the genetics of the fire ant S. invicta will help to better understand the underpinnings of social variation in this species and may aid in the development of novel management techniques.