Developmental sites of immature stages of the stable fly and house fly (Diptera: Muscidae) in cattle feedlot pens: Location, characterization, and associated arthropods

Random samples were taken for 3 yr from five sample areas in cattle feedlot pens. The goal was to determine where, when, and under what conditions occurred the development of immature stages of the stable fly, Stomoxys calcitrans (L.), and the house fly, Musca domestica L., (Diptera: Muscidae). Feedlots practiced either minimum (possible annual manure removal), intermediate (annual manure removal and possible insecticide use), or intense (manure removal and insecticide use scheduled several times annually) management to control fly pests\u27 populations. Immature stable flies were affected by feedlot management: managements ranked (highest to lowest numbers of flies) were minimum, intermediate, and intense. Numbers of immature house flies were not affected by feedlot management. The feed apron sample area consistently yielded the highest numbers of both pests. Immature stable flies were found predominantly in the early (cool) season; immature house flies were found predominantly in the later (warm) season. The number of stable fly immatures correlated strongly to adults in 1986 and 1987. At least 47 spp. of associated arthropods were found coinhabiting with these pests. The predominant predator ($\approx$17 spp. total) species was Platystethus cornutus Grav. (Coleoptera: Staphylinidae) while the predominant potential competitor ($\approx$30 spp. total) species was Coproica sp. (probably vagans) (Diptera: Sphaeroceridae). Predators were found in about equal numbers between feedlot managements and sample areas in all 3 yr. Potential competitors were found in about equal numbers between feedlot managements; along the feed apron was the predominant sample area in all 3 yr. The high percentage of organic matter at the feed apron was the major contributing factor to successful development of pests and competitors. Regression analysis showed potential for predicting numbers of immature stable flies. Immature stages of the stable fly appeared more sensitive to changes in the microhabitat than immature house flies. Improved manure management practices along the feed apron could significantly impact both fly species at cattle feedlots