EFFECT OF THE RED IMPORTED FIRE ANT (HYMENOPTERA, FORMICIDAE) ON DUNG-INHABITING ARTHROPODS IN FLORIDA

The effect of the red imported fire ant, Solenopsis invicta Buren, on the horn fly, Haematobia irritans L., and other arthropods associated with cowdung was evaluated in northcentral Florida pastures from Augus t to November 1992 and 1993. Workers of S. invicta were found to infes t fresh cowpats heavily and prey on horn fly larvae, pupae, and newly emerged adults. After the fire ant populations were controlled with a bait, Amdro (hydramethylnon), the numbers of horn flies and other musc id and sarcophagid flies emerged from cowpats were significantly great er than those from the untreated area. S. invicta caused 94.3 and 62.9 % mortality of horn flies for 1992 and 1993, respectively. It also red uced the populations of staphylinid, hydrophilid, and carabid beetles that are predators of horn flies. Despite this negative effect, S. inv icta was evaluated as an effective natural enemy of the horn fly.