Laboratory culture of beneficial dung scarabs

Cattle dung accumulation presents problems of pasture fouling, nutrient loss, intestinal parasitosis, and pest fly development. These problems have been confronted, with variable success, with the introduction of coprophagous scarabs (Coleoptera: Scarabaeidae). This work reports the results of field collections and laboratory culture of immature and adult dung scarabs. We compared several treatments of eggs and larvae in search of good methods for rearing scarabs in aseptic conditions. We collected 13 abundant species from northern and central Argentina. We obtained approximate to 4,500 eggs, some of which we sent to quarantine facilities in the United States, and others which we reared in our laboratory with 5 different techniques. Five common and widespread species, Ontherus sulcator (F.), Gromphas lacordairet Brulle, Dichotomius semiaeneus (Germar), Sulcophanaeus menelas (Castelnau), and Bolbites onitoides Harold, had the highest oviposition rates and were also the easiest to rear. Two methods, freeze-dried and gamma sterilized brood masses and balls, provided the best results (i.e., percentage of beetles completing development). As a rule, the species with short larval development time and wide distributions were easier to rear.