Background: The foraging preference of Atta mexicana for leaves of three plant species was analyzed under laboratory conditions. Physicochemical characterizations, bioassays with leaf material and crude extracts, and tests on the effect on the mutualistic fungus Leucoagaricus gongylophorus were conducted. Question: Does the interaction between A. mexicana and its mutualistic fungus influence the selection of Palicourea padifolia leaves over Platanus mexicana and Eriobotrya japonica? Species study: Atta mexicana, Leucoagaricus gongylophorus, Palicourea padifolia, Platanus mexicana, Eriobotrya japonica. Study site and date: Xalapa, Veracruz, Mexico, 2023. Methods: Foraging preferences were evaluated under laboratory conditions. Leaves were physically and chemically characterized. Insecticidal and antifungal tests with methanolic extracts were performed, and specialized metabolites were detected through qualitative assays. Results: A. mexicana preferred leaves of P. padifolia. Less selected species exhibited trichomes, higher toughness, and elevated levels of phenols, flavonoids, and tannins. In contrast, P. padifolia had glabrous leaves, high moisture, and low metabolite content, favoring its acceptance. Methanolic extracts showed no insecticidal activity. The extract of P. padifolia promoted the growth of L. gongylophorus, while those of P. mexicana and E. japonica moderately inhibited it. Conclusions: Atta mexicana preferred P. padifolia leaves due to their characteristics, and the extract promoted mutualistic fungus growth. Leaf toughness and trichomes were barriers to foraging. Trichome-removing behavior of A. mexicana is reported for the first time.