Agradecimentos: We are grateful to Rodrigo Feitosa, Juliane Lopes, André Freitas, and Alexander Christianini for discussions and comments on the manuscript. The final version of the manuscript was considerably improved by suggestions from Ladaslav Sodek and three anonymous reviewers. Flavio Roces helped with data analyses at early stages of the study. We thank Rodrigo Feitosa for identifying the ant, João Semir for identifying the mushrooms, Gustavo Romero for allowing the use of his lab facilities, and André Tacioli for assistance in the field. The Instituto de Botânica de São Paulo provided logistic support for fieldwork at the cerrado reserve in Mogi-Guaçu. A.C.C. was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; 152508/2016-3) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES – Finance Code 001). M.U.V.R. and H.S. were supported by CAPES (Finance Code 001). P.S.O. was supported by research grants from the CNPq (306115/2013-1, 302219/2017-0) and the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, BIOTA Program, 2014/23141-1, 2017/16645-1) Ver menos

Abstract: Fungus-farming ants cultivate a fungal symbiont inside the nest that serves as a food source. Leaf-cutter ants are distinctive among fungus-farmers because they forage for fresh plant material to nurture the fungus. Here we investigate the foraging ecology of Acromyrmex subterraneus(Fore)) in the Brazilian cerrado savanna. We examined the species activity pattern, forage material collected, and the relationship between load mass and forager size. Ant activity peaked at night and was negatively related to temperature but positively related to relative air humidity. The majority of the items collected by ants was plant material: dry and fresh leaves, flowers, and fruits.Trunk trails ranged from 0.7 to 13 m and colony home ranged from 2 to 28 m(2), indicating that ants collect material nearby the nest. Total load mass was positively associated with forager size, especially in the case of leaves. The negative relationship between ant size and burden suggests that ants might optimize their delivery rate by collecting lighter substrates more frequently. Given their pest status, most studies on leaf-cutters are undertaken in human-altered environments. Information on A. subterraneus in native cerrado is imperative given the threatened status of this vegetation. Leaf-cutters thrive in disturbed cerrado and severe seedling herbivory may hinder vegetation recovery. Our fieldwork may provide insights for management techniques of Acromyrmex colonies in agroecosystems, as well as for restoration programs of degraded cerrado areas Ver menos