Forest Modification Affects Diversity (But Not Dynamics) of Speciose Tropical Pyraloid Moth Communities

We studied temporal and spatial dynamics of extremely diverse moth ensembles (Lepidoptera: Pyraloidea) along a gradient of forest disturbance ranging from undisturbed primary tropical rain forest to different kinds of modified forest and open cultivated land at the margin of Mount Kinabalu National Park (Sabah, East Malaysia). We sampled moths by light trapping during two periods (March‐May and August‐September 1997). We collected a total of 7724 individuals representing 680 species during 78 light‐trapping nights at six study sites. Species diversity (Fisher's α) of ensembles in undisturbed primary forest was distinctly higher than in disturbed or secondary forest. More pyraloid moths were attracted in undisturbed primary forest. Samples from disturbed primary or old‐growth secondary forest were statistically indistinguishable from the undisturbed primary forest ensemble in regard to species composition. Thus, pyraloid ensembles from disturbed forest with tall trees remaining appeared to represent impoverished subsets of the undisturbed primary forest community. The more heavily disturbed sites had a distinct fauna and showed a stronger faunal differentiation among each other. Four species of the genus Eoophyla, in which aquatic larvae feed on algae in fast‐running streams benefited prominently from forest disturbance. Temporal variation of ensembles was remarkably concordant across the disturbance gradient. Relative abundance variation of the commonest species was identical at all sites. Overall, pyraloid moths responded more sensitively to anthropogenic habitat alteration than most other moth taxa studied thus far in tropical regions and allowed for an analysis of diversity patterns at a high temporal resolution.