First Record of Parasitoidism by Phoridae Flies in Atta opaciceps Borgmeier (Hymenoptera: Formicidae), a Leafcutter Ant from the Northeast Region of Brazil

Leafcutter ants of the genus Atta Fabricius, 1804 (Hymenoptera: Formicidae) are important actors in natural environments, as they are part of crucial ecological processes; however, they are also considered important pests in agroecosystems. Numerous species of flies from the Phoridae family have been recorded as parasitoids of several species of leafcutter ants, with details of their biology, life cycle, and forms of attack behavior. For the leafcutter Atta opaciceps Borgmeier, 1939, however, to date, there is no record of associated phorids or even records made in the state of Sergipe on the occurrence of parasitoid phorids. This study is the first to report the occurrence of phorids associated with A. opaciceps and the observed parasitoidism rates. Workers collected in the field were kept in the laboratory for parasitoid emergence. The parasitoidism rate was 8.4%, with the majority of workers being parasitized by Myrmosicarius grandicornis Borgmeier, 1928 (n = 267; 99%). There were two other records: one parasitized by Eibesfeldtphora declinata (Borgmeier, 1925) and another worker hosting Apocephalus setitarsus Brown, 1997. This study expands the knowledge about phorids associated with Atta in Brazil, including A. opaciceps on the list of natural hosts, the state of Sergipe in its distribution area, and information on parasitoidism rates.