Data from: Diversity partitioning confirms the importance of beta components in tropical rainforest Lepidoptera

Tropical beta diversity, and particularly that of herbivorous insects in rainforests, is often considered enormous, but this notion has recently been challenged. As tropical beta diversity is highly relevant to our view on biodiversity, it is important to gain more insights and resolve methodological problems that may lead to the contradictions in different studies. We used data on two ecologically distinct moth families from Southeast-Asia and analyzed separately the contribution of beta components to overall species richness at three spatial scales. Observed diversity partitions were compared under different types of null models. We found that alpha diversity was lower than expected from null models, whereas hierarchical beta components were larger than expected. Beta components played a significant role in shaping gamma diversity, and their contribution can be high (multiplicative beta >5). We found a reduction of beta components when comparing primary forests and agricultural sites (cf. “biotic homogenization”), but even in these habitats beta components were still substantial. Our analyses show that beta components do play an important role in our data on tropical herbivorous insects, and that these results are not due to lumping different habitats when sampling environmental gradients.