In 1989, the dung-beetle Onthophagus gazella Fabr. was imported from the United States to be part of the integrated control program of helminths and horn-fly, Haematobia irritans L. Because there is no information about the effects of pyrethroids on the African beetle survival, the effect of four commercial pour-on insecticides for horn-fly control, on dung-beetle survival was investigated. Fifteen 24 months old, Nelore steers, were randomly assigned to five groups, with three animals/group. Animals in group 1 (control) received no treatment. Groups 2, 3, 4 and 5 were treated on day 0 with Alphamethrin, Cyalothrin, Deltamethrin and Flumethrin, respectively. Individual samples of fecal material (approximately 100 g) were collected from the rectum, on days 1, 4, 8, 11, 15 and 18 after treatment and placed in 500 ml glass vials. Ten live beetles were added in each vial and the survival rate was determined. Beetle mortality was high (P<0,01) for all products and intervals after applications in comparison to that observed in the control group until 8 d after treatment, and drastically decreased up to the 18th day. There was no significant differences (P>0,01) in mortality rate among treated groups.
Insecta; Haematobia irritans; horn fly; pyretrhoids; cattle
