COPROPHILOUS ARTHROPOD COMMUNITY FROM ARGENTINA WITH SPECIES OF POTENTIAL USE AS BIOCONTROL AGENTS AGAINST PEST FLIES

Dung-inhabiting pest flies are one of the main problems associated wit h the accumulation of cattle dung. This work analyzes the diversity an d dynamics of a coprophilous community from northern Buenos Aires, Arg entina, in a search for potential biocontrol agents. Thirty-six dung p ads of 3 age categories and 4 microhabitats were collected on each sam pling date and examined for their arthropod fauna. Some of the species with undefined feeding behavior were subjected to feeding trials in t he laboratory. We found 34 coprophagous species, 47 predators, and 13 parasitoids. The combination of the results of the feeding trials, co- occurrence and abundance data of the prey and predator populations, an d direct field observations were used to put together a trophic web an d hypothesis on the dynamics of the community. Dung scarabs cause sign ificant reductions in immature dung fly survival by burying and desicc ating large amounts of dung. The Philonthini (Coleoptera: Staphylinida e) are the most abundant and rich predator group, although they are sl ow to respond to variations in fly populations. However, predatory fli es show the same abundance curves as their prey flies. Predatory beetl es and flies, dung scarabs, and pupal parasitoids cause additive morta lity to the fly population, whereas larval parasitoids cause some comp ensatory mortality. Four species of staphylinids, 1 predatory muscid, and a coprophagous scarab could have potential as biocontrol agents. T he perspectives of success and convenience of a horn fly biocontrol sc heme in southern South America are discussed.