Atta sexdens (Linnaeus, 1758)

Atta sexdens, along with A. cephalotes, is the most widespread member of its genus. Its northern most range is Mexico, and extends through Central America (Panama, Costa Rica, Guatemala, Nicaragua), into South America (Ecuador, Columbia, Peru, Bolivia, Venezuela, Guyana, Brazil, Surinam) and Trinidad and Tobago (Hölldobler & Wilson, 1990; Kempf, 1972; Weber, 1972). Atta sexdens is a considered a serious pest throughout its range, causing damage to a wide variety of agricultural crops and ornamentals (Cherrett, 1986). The species has a wider tolerance for nest habitats, and is found in closed-canopy-forest, open grassland and disturbed habitats (Solomon, 2007; Weber, 1969). A niche modeling analysis determined that temperature seasonality was the most important variable for predicting its current distribution, while precipitation seasonality was the least important (Solomon, 2007). The modeling also predicts A. sexdens could, should opportunities present themselves, expand its range to western Ecuador and islands in the Lesser Antilles, including Trinidad, and also on Hispaniola and Jamaica. Atta sexdens is a serious pest everywhere it occurs, and has been shown to readily colonize human-altered habitats such as parks and agricultural fields (Solomon, 2007; Weber, 1972; Zanúncio et al., 2002). Introduction of this species into habitats outside of its native range could have devastating effects (Hölldobler & Wilson, 1990; Mikheyev, 2008). A pest risk assessment of unprocessed Eucalyptus concluded the introduction of South American Atta species into the United States was a low probability (Kliejunas et al., 2001).