Arthropod Populations in Permanent Pastures Treated and Untreated With Mirex for Red Imported Fire Ant 1 Control 2

Abstract

Experiments were conducted in 1972–73 to study interrelationships between red imported fire ants, Solenopsis invicta Buren, 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 of Vacusus vicinus (LaFerte) (Anthicidae), Lycosa riparia-helluo complex (Lycosidae) and pupae of hom flies, Haemotobia irritans (L.) (Diptera) were significantly higher ( P S. invicta and Nylanderia spp. (Formicidae) were significantly lower ( P < 0.05) in treated compared to untreated pastrues in 1972. In 1973 significantly greater numbers of Trachelas deceptus (Banks) (Clubionidae), Carabidae, and H. irritans pupae were found in treated pastures. Significantly lower numbers of Schizoeoza avida (Walkenaer) (Lycosidae), Xyleborinus saxeseni (Ratzeburg) (Scolytidae), Staphylinidae, Aphodiinae, (Scarabaeidae), Gryllidae, S. invicta and Nylanderia spp. were detected in the treated pastures ( P S. invicta preyed upon immature forms of H. irritans in cattle dung pats. Where predation of immature horn flies was intense, associated rove beetles also were apparently preyed upon.