Tawny Crazy Ant

Nylanderia fulva — the tawny crazy ant, also called the Rasberry crazy ant after its 2002 Texas discovery — is one of the most consequential invasive ant species of the 21st century. Native to South America (Argentina, Brazil), the species was first detected in Houston in 2002 and has since established across the southeastern US from Texas to Florida. Three traits make her remarkable. First, the species runs in unpredictable zigzag patterns rather than orderly trails — the basis of the 'crazy' common name. Second, in 2014, LeBrun et al. at UT Austin documented the only known venom-detoxification behavior in insects: before engaging a fire ant in combat, the crazy ant grooms herself with her own formic acid, neutralizing the fire ant's piperidine-alkaloid venom and surviving stings that would otherwise be lethal. This explains why N. fulva is steadily displacing imported red fire ants (Solenopsis invicta) across the US South. Third, crazy ants form 'super-colonies' with no inter-nest aggression and reach densities exceeding 60 ants per square inch. The sheer biomass causes documented economic damage well beyond agricultural impact: swarms invade and short-circuit electrical equipment (pumps, A/C units, transformers, computers). The estimated economic damage in Texas alone exceeds $146 million per year.