BUSH FLY ABUNDANCE AND POPULATION EVENTS IN RELATION TO DUNG BEETLE CATCHES ON THE SOUTH COAST OF NEW SOUTH WALES

Abstract

Abstract Over 2 seasons, 1980–81 and 1981–82, the patterns of abundance of female bush flies, Musca vetustissima (Walker), at 3 field sites on the N. S. W. south coast varied little between sites but greatly between seasons. There was no direct relationship between the patterns of bush fly abundance and of native dung beetle catches at the same sites. Analysis of the results of dissection of the 1981–82 bush fly samples suggested that, although much oviposition had occurred, the mortality of the immature stages had been high. There was also more direct evidence that the bulk of the flies caught had recently immigrated, so that their numbers were largely independent of the results of local bush fly breeding. Although obscured by migrations of adult flies and by the high levels of immature mortality caused by other factors, the role of dung beetles as one of the causes could be inferred from the data to be of the same high order as indicated by published laboratory studies.