Effects of habitat disturbance can be subtle yet significant: biodiversity of hawkmoth-assemblages (Lepidoptera: Sphingidae) in Southeast-Asia
Sphingid biodiversity was compared in a large number of light-trapping samples on Borneo and elsewhere in the Indo-Australian tropics, using our own quantitative light-trapping samples supplemented by other collectors’ published and unpublished data. No effects of anthropogenic habitat disturbance on the within-habitat diversity (measured as Fisher’s α) were observed, but the faunal composition of assemblages differs significantly under varying degrees of disturbance. Altitude, year of sampling and sampling regime (full night vs. part of the night) were identified as additional parameters that influence the composition of local samples. The frequency of subfamilies in samples varies under different disturbance regimes: Smerinthinae decline along a gradient from primary habitats to heavily disturbed sites, while Macroglossinae show the reverse trend. Connections between the reactions of subfamilies to disturbance and altitude and potential life-history differences between the subfamilies are discussed. Hypothetically, capital breeding Smerinthinae might be commoner and more speciose in stable primary habitats, whereas many income breeding Macroglossinae are probably adapted to thrive in ephemeral, disturbed habitats. Furthermore, we show that estimates from local samples fall short of the total known species richness of Borneo by about 10%.