From 1992 to 2009, 334 trees were sampled by insecticidal knockdown on Borneo, Malaysia. Here, we describe the taxonomic composition of the 9671 specimens and 1589 species Curculionoidea collected (with additional notes on Cerambycidae). We found a largely unknown fauna with an assumed proportion of over 80% of species new to science, including all 33 Apionidae and 26 Ceutorhynchinae species. Specialists could usually identify only a few specimens leaving the remaining beetles for further investigation. The samples contain numerous genera, two tribes (Egriini, Viticiini), one subfamily (Mesoptiliinae) and one family (Belidae) new to Borneo and several genera not recorded west of the Wallace line before. These data show how little is known about canopy diversity. The lack of taxonomic knowledge implies a respective lack of autecological knowledge and is alarming. Some taxa differed conspicuously between primary and disturbed forests. In contrast to common literature, our results let us conclude that current efforts to narrow down the extent of tropical diversity and its ecological importance must consider the enormous species diversity of the canopy.

Arboreal spiders in deciduous and coniferous trees were investigated on their distribution and diversity. Insecticidal knock-down was used to comprehensively sample spiders from 175 trees from 2001 to 2003 in the Białowieża forest and three remote forests in Poland. We identified 140 species from 9273 adult spiders. Spider communities were distinguished between deciduous and coniferous trees. The richest fauna was collected from Quercus where beta diversity was also highest. A tree-species-specific pattern was clearly observed for Alnus, Carpinus, Picea and Pinus trees and also for those tree species that were fogged in only four or three replicates, namely Betula and Populus. This hitherto unrecognised association was mainly due to the community composition of common species identified in a Dufrene-Legendre indicator species analysis. It was not caused by spatial or temporal autocorrelation. Explaining tree-species specificity for generalist predators like spiders is difficult and has to involve physical and ecological tree parameters like linkage with the abundance of prey species. However, neither did we find a consistent correlation of prey group abundances with spiders nor could differences in spider guild composition explain the observed pattern. Our results hint towards the importance of deterministic mechanisms structuring communities of generalist canopy spiders although the casual relationship is not yet understood.