First published record of Atta opaciceps Borgmeier, 1939 (Hymenoptera: Formicidae) attacking neem (Azadirachta indica A.Juss.) in Brazil, with observations on foraging behavior

Abstract

This study reports the first published record of Atta opaciceps Borgmeier, 1939 (Hymenoptera: Formicidae: Myrmicinae) attacking neem trees (Azadirachta indica A. Juss., Meliaceae) in Brazil. Observations were conducted over eight consecutive days in an urban afforestation transect located at the Universidade Federal do Piauí, Bom Jesus campus. Intense foraging activity by an active colony resulted in progressive defoliation of Az. indica individuals. Soldier and worker ants were collected from different nest openings and identified based on external morphological characters through comparison with voucher specimens deposited in an institutional entomological collection and previously identified by a specialist; voucher specimens from the present study were subsequently deposited in a biological collection. Foraging activity was exclusively restricted to neem trees during the observation period and was characterized by the detachment of leaflets through petiolule cutting, followed by their fall to the ground and subsequent retrieval, with a low incidence of the typical semicircular cuts commonly observed on fresh leaf tissues. This harvesting strategy, previously reported for other Atta Fabricius, 1804 species foraging on neem, may represent a flexible behavioral response to the chemical defenses of this host, potentially reducing exposure to volatile bioactive compounds present in fresh tissues. These observations contribute to the knowledge of the interaction between At. opaciceps and neem and highlight the need for further studies to elucidate the mechanisms underlying this foraging behavior.