Relationship between Duration of Cattle Dung Exposure in Pastures, Its Average Crustal Thickness and Occurrences of Dipterous Insects and Their Parasitoids in South Goiás, Brazil

Abstract: The objective of this study was to investigate the relationship between duration of cattle dung exposure in pastures, its average crustal thickness and occurrences of dipterous insects and their parasitoids in south Goiás, Brazil. Parasitoids were collected after different durations of cattle dung exposure in pastures, in an experiment conducted in south Goiás, Brazil, between January and October 2001. Cattle dung pads were exposed in pastures for periods of 24, 48, 72, 96, 120, 144, 168, 192, 216 and 240 hours were then individually taken to the laboratory for parasitoid extraction. A total of 100 dung pads were exposed in pastures and 430 parasitoid individuals were recovered from them. The most abundant species extracted were: Paraganapis egeria Díaz, Gallardo & Walsh (Hymenoptera: Figitidae) and Spalangia drosophilae Ashmead (Hymenoptera: Pteromalidae). The majority of the species were collected from cattle dung pads exposed for 144  and 240 hours. The largest number of individuals was found in feces with 240 hours of exposure.