SCIENTIFIC NOTE First Record of Phorid Parasitoids (Diptera: Phoridae) of the Leaf-Cutting Ant Atta bisphaerica Forel (Hymenoptera: Formicidae)

RESUMO - Moscas da familia Phoridae parasitam varias especies de formigas, inclusive diversassauvas (Atta spp.). Nesta nota sao relatados ataques de tres especies de forideos (Myrmosicariusgrandicornis Borgmeier, Apocephalus attophilus Borgmeier e Neodohrniphora bragancai Brown)contra operarias de Atta bisphaerica Forel em uma area de pastagem localizada em Vicosa, MinasGerais. As duas primeiras especies ja sao conhecidas como parasitoides de outras sauvas, mas N.bragancai foi recentemente descrita e encontrada somente ao redor de ninhos de A. bisphaerica . Cadauma dessas especies de forideos seleciona operarias que realizam diferentes tarefas e oviposita empartes especificas do corpo do hospedeiro.PALAVRAS-CHAVE: Parasitismo, comportamento de oviposicaoABSTRACT - Phoridae flies parasitize several ant species, including many Atta leaf-cutting ants. Inthis note, the attacks of three coexisting phorid species (Myrmosicarius grandicornis Borgmeier,Apocephalus attophilus Borgmeier and Neodorhniphora bragancai Brown) against Atta bisphaericaForel workers in a pasture located in Vicosa County, Minas Gerais State, Brazil, are reported. The firsttwo species of phorids are known to parasitize other leaf-cutting ants. N. bragancai , however, has beenfound only around A. bisphaerica nests. Each of these phorid species selects ants engaged in differenttasks and oviposits in specific sites of the ant body.KEY WORDS: Parasitism, oviposition behaviorThe leaf-cutting ant Atta bisphaerica Forel is a grassspecialist (Fowler et al. 1989) and an increasingly importantpest of pasture and sugarcane in Brazil (Della Lucia 1999).Despite the relevance of A. bisphaerica , its ecology is poorlyunderstood. Other Atta species are hosts of several phorid(Diptera) parasitoids (Borgmeier 1928, 1931; Feener M Disney 1994, 1996), but there are no recordsof phorid species attacking A. bisphaerica (B.V. Brown andH. Disney, personal communication). The purpose of thisresearch was to find phorid parasitoids associated with A.bisphaerica and to determine their biological and behavioralcharacteristics.In July 1999, three field trips were made to a pasturecontaining several A. bisphaerica adult nests (at least three-year old) in Vicosa County, Minas Gerais State, Brazil. Tripswere made after 3:00 PM, when foraging ants have beguntheir activity. At each visit, trails and foraging areas wereinspected for approximately 2h while ants were active duringlate afternoon, and phorid presence and oviposition behaviorwere recorded. Three phorid species were found:Apocephalus attophilus Borgmeier, Myrmosicariusgrandicornis Borgmeier and Neodohrniphora bragancaiBrown. The first species is a parasitoid of Atta cephalotes(L.), Atta colombica Guerin, Atta laevigata (F. Smith) andAtta sexdens (L.) (Borgmeier 1928, 1931; Feener & Moss1990) while M. grandicornis parasitizes A. sexdens (Feener& Moss 1990) and A. laevigata (M. Braganca, personalobservation). N. bragancai however, is a recently describedspecies (Brown 2001) that has been reared from A.bisphaerica by the senior author. Voucher specimens of thethree species of phoris were deposited at the Museum ofEntomology at the Universidade Federal de Vicosa.