Altitudinal patterns of abundances and parasitism in frugivorous drosophilids in west Java, Indonesia

Abundances and parasitism rates of frugivorous drosophilid flies were studied in three localities at altitudes of 250–1350 m in and near Bogor, Indonesia. The drosophilid and parasitoid species were classified into four groups: low-altitude species, high-altitude species, species abundant at a mid-altitude location and species occurring rather evenly from low to high locations. The ananassae and immigrans species groups were major drosophilids collected. All species of the ananassae species group were more abundant at lower altitudes, and the parasitism rate in this species group decreased with increasing altitude. Thus, the host abundance seems to affect the parasitism rate. On the other hand, the rate of parasitism in the immigrans species group showed no apparent relation with altitude or density, possibly due to the fact that species of this species group variedin altitudinal distribution. It is also suggested that the diversity of drosophilid species affects the composition of parasitoid species.Keywords: abundance; altitude; frugivorous drosophilids; Indonesia; parasitoids; tropics Journal of Natural History, 49:27-28