Nuisance flies on Australian cattle feedlots: immature populations.

Species composition, seasonality and distribution of immature fly populations on a southern Queensland feedlot during 2001-2003 were determined. Similar data were collected on feedlots in central New South Wales and central Queensland. The fly species recovered in the highest numbers were Musca domestica L. (Diptera: Muscidae), Stomoxys calcitrans L. (Diptera: Muscidae) and Physiphora clausa Macquart (Diptera: Ulidiidae). Houseflies were the dominant species at all feedlots. Houseflies preferred the warmer months from October to June, but stable flies preferred the cooler months and peaked in spring (September-November) and autumn (March-May). Larval abundance ratings recorded in the feedlot and numbers of larvae extracted in the laboratory from corresponding samples followed similar trends. Larvae of M. domestica were most abundant in the hospital and induction area and least abundant in horse stables and yards. Pupae of M. domestica were abundant in the hospital and induction area and drains, but least abundant in horse stables and yards. Larvae of S. calcitrans were most abundant in drains and least abundant in horse stables and yards. Pupae of S. calcitrans were most numerous in drains and least numerous in old cattle pens. Feedlot design and management had little effect on fly reduction.