The genus Wasmannia in Argentina: distribution and taxonomy

CUEZZO, FABIANA; CALCATERRA, LUIS; CHIFFLET, LUCILA; FOLLETT, PETER

Petrópolis

Simposio; XX simposio de Mirmecología y I Encuentro de Mirmecólogos de las Américas; 2011

The genus Wasmannia (Formicidae: Myrmicinae: Blepharidattini) is endemic to the Neotropics, with 10 species presumably occurring through its native range from Argentina to Mexico, according to the last taxonomical review by Longino and Fernández in 2007. The little fire ant Wasmannia auropunctata is the most widely distributed species of the genus, being present from central-eastern Argentina to Bermuda. It has spread fairly recently around the Pacific and Atlantic islands and the Mediterranean region (e.g. Israel) and has become a serious pest in Hawaii and Galapagos, disrupting agricultural practices and threatening wildlife. Wasmannia rochai is the second most common species, occurring from Guatemala to Sao Paulo, Brazil. Three other scarcely collected and little known species, W. lutzi, W. affinis, and W. scrobifera, occur mostly with the other two in the Atlantic forest in southeastern Brazil. The objective of this work was to study the taxonomy and distribution of Wasmannia in its southern distribution. Of the three species reported for Argentina, only W. auropunctata was found to be widely distributed (but only very abundant in disturbed habitats), while W. sulcaticeps and W. williamsoni were less common and endemic. W. sulcaticeps was mainly found in mountain forests in northwestern Argentina (Yungas ecoregion), overlapping with W. auropunctata at ~700 meters of altitude, while W. williamsoni was only found in its type locality in Castex (Espinal ecoregion), in La Pampa province in central Argentina. We also (1) described one new Wasmannia species recently discovered in gallery forests in northeastern Argentina and previously reported for Concepción, Paraguay; (2) re-described W. williamsoni after 59 years of its discovery in Castex; (3) discovered W. rochai in Misiones province, northeastern Argentina; (4) re-described queens and males of W. auropunctata including several gynandromorphs (specimens with their left side similar to a male and right side similar to a queen) found in Colón, Entre Ríos province; (5) found a fungus (putatively a Myrmicinosporidium sp.) as potential natural enemy of the little fire ant; (6) provide a key for the five Wasmannia species present in Argentina based on worker morphology; and (7) made a cladistic analysis based on morphological characters to clarify the phylogenetic relationships among all known Wasmannia species.