Host characteristics related to host use by the flesh fly, Blaesoxipha japonensis (Diptera: Sarcophagidae), a parasitoid of adult grasshoppers

Abstract

We periodically collected adult grasshoppers of Parapodisma tanbaensis and P. subastris, in Kyoto, Japan, from 2001 to 2002, to determine which host characteristics were related to host use by the flesh fly, Blaesoxipha japonensis. The results indicated three host characteristics that were significantly related to the parasitism rate: host species, condition of the hind legs, and interaction between sex and body size. P. tanbaensis was parasitized more often than P. subastris because of its superior intrinsic quality. Grasshoppers missing one or both hind legs were parasitized more often than intact individuals. Female grasshoppers are twice the size of males, and smaller females were parasitized more often than larger ones, whereas larger males were parasitized more often than smaller ones. Host characteristics related to the number of larvae egressing from the host were similar to those of the parasitism rates, except for the interaction between sex and size. In addition, host sex was also an important characteristic, as more larvae egressed from female hosts.