The foraging behaviour of redlegged earth mite,Halotydeus destructor(Acarina: Penthaleidae), in an annual subterranean clover pasture

Abstract

AbstractThe foraging behaviour of the redlegged earth mite,Halotydeus destructor(Tucker), in annual pasture was documented and the relative numbers of individuals foraging on subterranean clover,Trifolium subterraneum(Leguminosae), capeweed,Arctotheca calendula(Compositae) and grasses (mainlyLolium rigidum(Gramineae)), estimated in winter and spring in south-western Australia. The main feature ofH. destructorforaging behaviour was the presence of aggregations ranging in size from 3–36 individuals on the adaxial surfaces of the upper canopy of the pasture. Most aggregating individuals were feeding, while most solitary and paired individuals were searching. There was no evidence that individuals aggregated for reproductive behaviour; the adult sex ratio was similar to that of the population even though immatures were under-represented in aggregations. During winter the distribution of numbers ofH. destructoron subclover, capeweed and grasses in the upper canopy of pasture was similar to the estimated ground cover of these plant species. However, individuals showed host-plant selection for subclover when feeding. During spring, when the pasture plants were flowering, there were moreH. destructorin capeweed flowers than in aggregations on subclover foliage. The capeweed flowers were shown to enhance the rate ofH. destructorreproduction in a laboratory experiment. MostH. destructorwere on or near the soil surface, with 10% at any one time on the upper canopy of the pasture.H. destructoris polyphagous, and behaved in pasture as a selective opportunist feeder.