Insect Effects on Bacteria and Fungi in Cattle Dung

tion in Wyoming and Michigan. At both sites, screen cones placed over fresh dung were used to exclude insect colonists and confine normal field densities of Aphodius beetle adults or enough sarcophagid adults to produce normal larval densities. The effect of these insects on bacterial and hyphal densities as well as on fungal species numbers was assayed after the dung had been in the field 3 to 4 wk. Presence of maggots and Aphodius beetles increased bacterial and decreased hyphal density in Wyoming but not in Michigan. We hypothesize that these effects are due to insect mixing of the substrate, giving bacteria a competitive advantage over fungi. Normal insect colonization increased the number of fungal species per pat in Michigan and Wyoming, although the total number of fungal species was not affected by treatments.