Initial Assessment of the Impact of the Recent Invader, Solenopsis invicta Buren, on Resident Ant Assemblages in Matamoros, Mexico

Abstract. The red imported fire ant, Solenopsis invicta Buren, is exotic to Mexico. It has been detected recently at least 3 km south of the Texas-Mexico border, in Matamoros, Tamaulipas, Mexico. Previous studies in the USA have indicated that the arrival and establishment of the red imported fire ant has resulted in reductions of density and diversity of resident ant populations; S. invicta also modifies the associations with and among other ant species. This initial ecological study was conducted from 2007 to 2009 in Matamoros, Mexico, to assess the impact of the red imported fire ant on relative density, diversity, and interspecific associations of other resident ants. The goal of the study was to determine the impact of the imported fire ant infestation on remaining resident ants in two habitat types: (agricultural fields and natural habitats) in adjacent S. invicta infested and non-infested areas. Pitfall traps were used to estimate ant abundance and diversity. A total of 31,838 ants (12,515 in the n...