Does the Ant Functional Group Classification Really Work? A Validation in Two Contrasting Habitats from Central Mexico

Ants have historically been classified into “functional groups” (FGs) to facilitate their interpretation as bioindicators. A particularly popular classification scheme is the one proposed by Andersen, based on the Australian myrmecofauna. These classification criteria suggest that ant abundance is linked to stress and disturbance, such that their affinity to and tolerance of particular conditions enables them to inhabit specific ecological contexts. Herein, we aimed to validate whether the climatic affinity postulated by the FG approximation can suggest FG composition and abundances in Mexican ant communities, such as has been previously evaluated by studies in other regions worldwide. In a protected natural area with a history of anthropogenic pressure, we evaluated the variation in temperature and humidity of two habitat types during consecutive years: a native oak forest and an induced grassland. The ant communities of the two sites were monitored using three collected methods (baits, pitfalls, and direct observations) and classified into FGs under Andersen’s criteria. We found 34 ant species. The induced grassland site (28 species) was more species rich, more diverse, and had higher ant abundance than the oak site (21 species). There was a similarity in species composition between the sites (44.78%). In the oak forest, FGs related to cold temperatures were the most abundant, while in the induced grassland, heat-tolerant FGs were most abundant. Our findings support that Andersen’s functional group classification is useful in suggesting habitat use in Mexican ant species. Likewise, our data are in accordance with previous findings that both the presence and abundance of FGs must be considered for an adequate application of this classification scheme.