Insects (Arthropoda: Insecta) collected on bovine feces after different times of field exposure in Itumbiara, South of Goias, Brazil

T he collected of insects in cattle dung deposited in pasture were observed from Janaury to August 2001 in Itumbiara, Goiás, Brasil. Cattle dung pats were exposed at a pasture for 24, 48, 72, 96, 120, 144, 168, 192, 216 and 240 hours and were than taken to labortory separate from each other, for parasitoids extraction. A total of 100 dung pats were exposed at pasture. Were recovered 3229 Scarabaeidae, 3099 Diptera and 430 Hymenoptera (parasitoids). T he most abundant species Diptera were Palaeosepsis spp. e Sarcophagula occidua and parasitoids: Paraganapis egeria and Spalangia drosophilae and Scarabaeidae: Ataenius aequalis e Aphdodius lividus. T he periods of the highest population peak were: 24, 48 and 72 horas.


Introduction Introduction
Among the insects, stands out the group of the muscideous dipterans from the families Calliphoridae, Sarcophagidae end Muscidae, which have great medical and veterinarian importance since they may be mechanical and biological vectors of microorganisms pathogenic to man and domestic animals. Besides, they are considered a problem for public health in many areas of the world once they may invade residences and working places becoming an annoyance for the population (GUIMARÃES et al., 1983).
T he main pest-species that develop on this type of substrate are Musca domestica (L) and Stomoxys calcitrans (L), which develop mostly on feces of confined cattle, as well as Qeios, et al., 1999;AIDAR et al., 2000) as well as in controlling bovine gastrointestinal parasite nematodes; besides improving soil structure and fertility (FLET CHMANN et al., 1995).
T hey present a typical behavior of burying small portions of fecal mass in the soil and build galleries causing soil aeration and drying and, concomitantly, burying larvae and eggs that by chance are present in the manure attacked by them (FLET CHMANN et al., 1995 T he farm has approximately 29 hectares and 50 dairy "girolanda" bovine cattle heads.
Fresh feces were collected immediately after being excreted in the corrals and mixed in two 20 liters plastic buckets.
Feces pads, of approximately two liter each, were then made and placed into 10 plastic trays (40 cm in diameter and 12 cm in height) containing a 5 cm layer of soil from the same site. T he trays were bottom-perforated to allow rainwater drainage. T hese so prepared trays were then placed at the soil line in the field at 9:00 o'clock AM for arthropods visitation.
At each one day interval, one pad was collected after 24,48,72,96,120,144,168,192,216, and 240 hours of field exposure and taken to the laboratory. T hese trays were covered with cheesecloth and maintained in the laboratory for pupae collection using the flotation method. Pupae were individualized into gelatin capsules (number 00) and maintained in the laboratory until parasitoids hatching. It is also shown on T able 1 that the species T richopria sp. (Hymenoptera: Diapriidae), Neralsia splendens (Hymenoptera: Figitidae), P. egeria, and Aleochara notula (Coleoptera: Staphylinidae) were collected in feces with 24, 48, and 72 h of exposure indicating that they probably are parasitoids of larvae of muscoids dipterans. According to DIAZ & GALLARDO (1995;1996) With the results obtained up to the moment it was found that the larger action of the parasitoid species occurred in the fresher fecal plates (T able 1) with exposure times of 24 and 96 h. In the ecological succession of insects that occur in bovine feces, only the species found in fresher feces (24 and 48 h) would be more indicated for selection aiming a future horn fly control program.
As far as preference of species as related to time of exposure is concerned, the following results were achieved: T richopria sp. preferred feces exposed for 72 and 192 hours; P.
Ataenius aequalis Harold was the most abundant species (67.3%) followed by the species Aphodius lividus Balth (10.7%) among the Scarabaeidae collected (T able 1). It is believed that these species are the most well adapted to pasture areas in the Itumbiara area.
T hese two species were also collected in an experiment carried out by MARCHIORI et al. (2001) at the same location, on feces exposed in the pastures for 196 hours.

Conclusion Conclusion
T here is a large diversity and abundance of arthrpods species that develop on bovine feces in the pastures of the region studied. T hese species presented population peaks on feces exposed in the field for 24, 48 and 72 hours.