Dipterous parasitoids collected from cattle dung in Goinia, region central Gois, Brazil

T his study had the objective of determining the species of parasitoids in pupae of Diptera present in bovine dung, collected in the municipality of Goiânia, GO, region central of Brazil, from March 2012 to February 2013. T he dipterous pupae were obtained by the flotation method. T hey were individually placed in gelatin capsules until the emergence of the dipterous and/or their parasitoids. T he overall percentage of parasitism was 6.5%, and Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) was the species with the highest percentage of parasitism with 9.8%. T he more frequent specie was: Aleochara notula Erichson, 1839 (Coleoptera: Staphylinidae) with 26,1%.


Introduction Introduction
Among the means for controlling flies, chemical insecticides are the most widely used.
However, these may lose their efficiency as populations become resistant to them (Silveira et al., 1989). T he appearance of resistance to insecticides explains the growing need to introduce alternative control programs aimed towards fly control.
Parasitoids are agents responsible for reducing the populations of flies that proliferate on dung (Marchiori et al., 2001), cadavers and animal carcasses. Because parasitoids occupy a higher trophic level, they often act as determinant factors for the population density of their hosts, consequent to their great diversity of physiological and behavioral adaptations. T hese insects are considered to be bioindicators of the biodiversity of ecosystems and are considered to be key species for maintaining the equilibrium of the communities in which they are included. In addition, since they are natural enemies of agricultural pests, they may be used in biological control programs (Scatolini and Dias, 1997).
T his study had the objective of determining the species of parasitoids of dipterous insects that were present in bovine feces collected in Goiânia (central regions of the state of Goiás), Brazil.

M aterial and M ethods M aterial and M ethods
In Goiânia, the experiment was conducted at the Veterinary and Zootechnics School of the Federal University of Goiás, in the municipality of Goiânia (16º40'S and 49º16"W).
Every fortnight, 10 plates of fecal cake (of approximately 3 kg each) were produced from fresh bovine feces that were collected immediately after defecation in pastures of Brachiaria brizantha (Hochst ex. A. Rich) and in corrals.
T he material was collected in plastic buckets and was homogenized. It was then placed in 10 round plastic supports of 20 cm in diameter, with a hole to allow rainwater to drain away. T his methodology was used for precise determination of the time between the emission of the fecal cake and its collection. T he feces remained exposed (five in the pastures and five in the corrals) for 15 days. After this period, the feces were taken to the laboratory for extraction of pupae by means of the flotation method.
T he pupae were removed with the aid of a sieve; they were counted and individually stored in gelatin capsules (number 00) until the flies and/or parasitoids emerged. T he parasitoids and flies that emerged were identified with the aid of a stereoscopic microscope and were conserved in 70% alcohol.
T he percentage parasitism of each parasitoid species was calculated by means of the number of pupae parasitized by each parasitoid species divided by the total number of pupae of that host, and multiplied by 100. T he parasitoids' preference for their hosts was tested by means of the chi-square test, with 5.0% probability. T he voucher material from the central region was deposited at the laboratory of the Veterinary Parasitology Center of UFG.  (Marchiori et al., 2005), all of which belong to the southern municipalities of Goiás.
It could be seen that in the southern region, greater diversity and quantity of parasitoids was obtained than in Goiânia. T he lower diversity in the central region was probably related to the low synanthropy of the species of dipterans and parasitoids collected in the region studied. T he locality studied is now surrounded by human populations on all sides.
T he most frequently observed species in Goiânia was Aleochara notula Erichson, 1839 (Coleoptera: Staphylinidae), accounting for 26.1% (T able 1), T his was probably due to its capacity to seek hosts or due to variations in the quality and availability of food resources.
T he larval phase of A. notula behaves as a solitary ectoparasitoid of pupae of Cyclorrhapha dipterans of the families Muscidae, Anthomyiidae, Coelopidae, Sarcophagidae and Psilidae (Wright and Müller, 1989). In the adult phase, it behaves as a predator of eggs and larvae of these dipterous insects and can be used for biological control of flies.
T he overall percentage of parasitism contacted was 6.4%. T hese variations in monthly percentages of parasitism may be associated with seasonal changes in environmental conditions. Nasonia vitripennis (Walker, 1836) (Hymenoptera: Pteromalidae) was the species in the central region that presented the highest percentage parasitism, with 9.8% (T able 1).
T his was probably due to variations in the quality and availability of food resources or due to the ability of this species to search for food, or possibly because it is a polyphagous parasitoid.  (Rivers and Denlinger, 1995). It is a polyphagous insect that parasitizes more than 68 dipterous species (Whiting, 1967).
In relation to the attraction of parasitoids towards dipterous insect in Goiânia, it was found that A. notula was attracted to Sarcophagula occidua Fabricius (Diptera: T his paper reports the first survey of parasitoids associated with cattle dung flies in the region Goiânia, Goiás, Brazil.