Mycophagy of Attini Ants (Hymenoptera, Formicidae, Myrmicinae) with Agaricales Mushrooms (Basidiomycota, Agaricomycetes) at Riparian Zone in Southern Brazil

Attini ants (Hymenoptera, Formicidae, Myrmicinae) have great diversity in exploiting food resources. However, little is known about the mycophagy involving Agaricales fungi (Basidiomycota, Agaricomycetes). Moreover, these associations are of paramount importance in riparian zones, as the interaction among soil, fauna and flora is fundamental to the maintenance of these environments. Thus, the aim of this study was to describe cases of mycophagy between ants and fungi in order to understand how these associations occur in riparian zones. To this, collections were made between 2021-2022 in the valleys of the Rio Vacacaí, Rio dos Sinos and Rio Pardo in the state of Rio Grande do Sul, Brazil. The samples were analyzed for characters macro and microscopic and identified taxonomically. Mycophagy activities of six species of ants worker were cataloged, among them Acromyrmex niger, Acromyrmex versicolor, Tranopelta gilva, Tranopelta subterranea, Pheidole flavens and Mycetosoritis hartmanni, which included in their diet the mushrooms Agaricus rufoaurantiacus, Macrocybe titans, Agrocybe underwoodii, Dactylosporina steffenii, Lepiota micropholis and Neopaxillus echinospermus, respectively. The observed interactions demonstrate the dispersal of fungal spores through ant body structures, such as legs, antennae, thorax and abdomen; basidiomata as aliment source, such as pileus, lamellae and stipe; and generalized and specialized levels of predation on various fungi structures. Our results demonstrate unprecedented mycophagous relationships and show that Agaricales fungi can be considered a food source for Attini in riparian zones in Brazil south.