Experiments were conducted in 1972–73 to study interrelationships between red imported fire ants,Solenopsis invictaBuren, and associated arthropods in pastures. The fire ant populations were suppressed with one application of mixrex bait each year. Frequencies of 30 arthropod taxa caught in pitfall traps and 5 insect taxa in dung samples were determined in mirex treated and untreated pastures. The population ofVacusus vicinus(LaFerte) (Anthicidae),Lycosa riparia-helluocomplex (Lycosidae) and pupae of hom flies,Haemotobia irritans(L.) (Diptera) were significantly higher (P<0.05) and Aphodiinae (Scarabaeidae),S. invictaandNylanderiaspp. (Formicidae) were significantly lower (P<0.05) in treated compared to untreated pastrues in 1972. In 1973 significantly greater numbers ofTrachelas deceptus(Banks) (Clubionidae), Carabidae, andH. irritanspupae were found in treated pastures. Significantly lower numbers ofSchizoeoza avida(Walkenaer) (Lycosidae),Xyleborinus saxeseni(Ratzeburg) (Scolytidae), Staphylinidae, Aphodiinae, (Scarabaeidae), Gryllidae,S. invictaandNylanderiaspp. were detected in the treated pastures (P<0.05).Examinations showed thatS. invictapreyed upon immature forms ofH. irritansin cattle dung pats. Where predation of immature horn flies was intense, associated rove beetles also were apparently preyed upon.