Predation by the Introduced Phoretic Mite, Macrocheles peregrinus (Acari: Macrochelidae) on the Buffalo Fly, Haematobia irritans exigua (Diptera: Muscidae) in Australia1

Abstract

The effectiveness of Macrocheles peregrinus (Krantz) as a predator of buffalo fly, Haematobia irritans exigua (De Meijere), was examined. In laboratory tests, mites were confined with eggs or larvae of buffalo fly to assess the effect of prey location and predator / prey ratio on fly survival, to determine the main life stage attacked, and to determine the prey preference of the mite in the presence of other fly species. In field tests, impact of the mite on buffalo fly survival was measured in natural field pats enclosed in screen cages. Buffalo fly mortality was highest when eggs of this species were placed on top of dung pats rather than beneath them. Maximum mortality obtained was 83%; there was no increase in mortality at predator/prey ratios above one mite per two fly eggs. The mite caused highest mortality when exposed to hatching eggs and young larvae of buffalo fly, but it showed a strong preference for eggs of other dipteran species that have softer egg chorions. Mites acting alone caused an average of 33% suppression of buffalo fly breeding in field pats. Macrocheles peregrinus was judged to be a relatively ineffective predator of buffalo fly.