Ocorrência e características biológicas de forídeos parasitóides (Diptera: Phoridae) da saúva Atta laevigata (Smith) (Hymenoptera: Formicidae) em Porto Nacional, TO

Abstract

Occurrence and Biological Characteristics of Parasitoid Phorids (Diptera: Phoridae) of the Leaf-Cutting Ant Atta laevigata (Smith) (Hymenoptera: Formicidae) in Porto Nacional, TO, BrazilABSTRACT -The purpose of this study was to verify the occurrence of parasitism in Atta laevigata (Smith) by phorids in Porto Nacional, Tocantins, Brazil and to evaluate some biological characteristics of those flies. From October/2002 to September/2003, at 15-day intervals, 22 samplings were carried out (149.5 ± 82.9 workers each) comprising 3,704 ants. In the laboratory, the ants were distributed in groups of five individuals per petri dish and maintained at temperature of 25 ± 1ºC and 80 ± 5% of RH. They were fed daily with a 50% honey solution until death. The total of 106 workers (2.8%), collected with or without load (plant fragment), were parasitized by phorids: 72 workers (68%) were parasitized by Apocephalus vicosae Disney, 28 individuals (26.4%) by Neodohrniphora erthali Brown, and six (5.6%) by Apocephalus attophilus Borgmeier. The higher parasitism rates by A. vicosae (3.9-5.4%) were observed during the dry season (June-August), while the parasitism by N. erthali was lower than 2.3% throughout the year. The bigger workers were parasitized by bigger parasitoid N. erthali or by parasitoid with larger number of larvae A. attophilus. The occurrence of three phorid species in Tocantins broadens the distribution of these flies in Brazil. The development of A. vicosae larva within the thorax of the host as well as the rupture between the ant pronotum and propleuron so that the emergence of the fly can take place are characteristics not yet described on parasitism of leaf-cutting ants by phorids.

Phorid Flies Parasitizing Leaf-Cutting Ants: Their Occurrence, Parasitism Rates, Biology and the First Account of Multiparasitism

“…The flies A. vicosae, A. attophilus and E. erthali had already been found attacking A. laevigata in the region of Porto Nacional (Bragança & Medeiros, 2006), but this is the first time M. grandicornis has been found attacking that host in that zone. Thus, this work expands the list of parasitic phorids present in the savannah region of Brazil.…”

“…At the same time, samples were taken from three other colonies of A. sexdens, localized in the neighboring city of Palmas (10° 10' S, 48°24'W). One to two hundred ants were collected from one or two trails of each colony, at random, in intervals of 15 days, between 7:00pm and 10:00 pm, following Bragança & Medeiros (2006), although not all of the colonies were always sampled.…”

“…These were individually taken into test tubes (13 mm X 100 mm) sealed with cotton and also kept in the acclimatized chambers. This procedure was adhered to for up to 15 days, at the end of which the parasitized ants are expected to be all dead (Bragança & Medeiros, 2006;Bragança et al, 2009a). In the same day of the ant's death or at most in the following day, the parasitized ants were inspected to check for the presence of phorid pupae in different parts of the host or next to it.…”

Características biológicas e comportamentais de Neodohrniphora elongata Brown (Diptera, Phoridae), um parasitóide da saúva Atta sexdens rubropilosa Forel (Hymenoptera, Formicidae)

“…Embora causem baixos índices de parasitismo natural em saúvas (2 a 4%), os forídeos são capazes de alterar negativamente o comportamento de forrageamento de seus hospedeiros, principalmente pela diminuição do número e tamanho das forrageadoras ao longo das trilhas e da massa de fragmentos vegetais transportados para o ninho (Orr 1992;Bragança et al 1998;Tonhasca et al 2001). Esses parasitóides podem coexistir em uma mesma trilha de forrageamento de Atta spp., selecionando operárias de diferentes classes de tamanho para atacar e, consequentemente, podem ter um efeito combinado na redução do forrageamento (Tonhasca et al 2001;Bragança & Medeiros 2006).…”

Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas

“…The phorid flies that parasitize ants use the host's body to complete their life cycle, and their occurrence is restricted by certain conditions, such as habitat structure, temperature and relative humidity (Folgarait et al 2007;Almeida et al 2008;Elizalde & Folgarait 2010). In addition, parasitoid abundance may depend on host foraging activity (Tonhasca Jr. 1996), and the form of attack or oviposition site (such as nest entrance holes or foraging trails) vary among phorid species (Erthal Jr. & Tonhasca Jr. 2000;Bragança & Medeiros 2006;Gazal et al 2009;Elizalde & Folgarait 2011, 2012. Recently, three species of phorid flies were described attacking workers of A. robusta, two of them were recorded only in Rio de Janeiro: Eibesfeldtphora breviloba Brown and Myrmosicarius exrobusta Brown (Brown et al 2012).…”