Beyond urban boundaries: the invasive ant Wasmannia auropunctata (Roger, 1863) (Hymenoptera, Formicidae) now reaching Iberian coastal habitats

Abstract

The little fire ant (Wasmannia auropunctata), notable for its minute size and painful sting, has emerged as a significant threat in Mediterranean Europe. This widespread exotic species is well-known because of its invasive nature, impacting biodiversity, public health, and economic activities. Noted for the first time in Málaga (S Spain) in 2018, it has since expanded to other locations in the same province. Here we report the presence of W. auropunctata in La Marina (Alacant province, SE Spain), representing the fifth recorded population on the Iberian Peninsula and the first occurrence outside Málaga province. The species was found infesting a coastal area of approximately 5.1 hectares, with workers being observed in foraging trails across multiple surfaces and living in dense concentrations both indoors and outdoors. Exclusion of native ant species within the occupied area and direct engagement in combat with other species was observed. The population was discovered in September 2024; however, based on infestation density, spatial extent, and comparison with data of other Mediterranean exotic populations, the species likely established in the region prior to 2019. For the first time in Iberia, W. auropunctata was also detected in the coastal dunes adjacent to the infested urbanised area, highlighting its potential adaptability to dry Mediterranean habitats. The resilience of W. auropunctata, combined with its aggressive invasive traits and pro-pensity to sting, underscores the urgent need for integrated management strategies to limit further expansion of the species in Iberia.