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Keywords:

  • Canopy crane;
  • feeding guilds ;
  • flower-visitors;
  • herbivory ;
  • wet tropics

Reliable estimates of host specificity in tropical rainforest beetles are central for an understanding of food web dynamics and biodiversity patterns. However, it is widely assumed that herbivores constitute the majority of host specific species, and that most herbivore species feed on leaves. We tested the generality of this assumption by comparing both plant host- and microhabitat-specificity between beetle communities inhabiting the foliage (flush and mature), flowers, fruit, and suspended dead wood from 23 canopy plant species in a tropical rainforest in north Queensland, Australia. Independent of host tree identity, 76/77 of the most abundant beetle species (N ≥ 12 individuals) were aggregated on a particular microhabitat. Microhabitat specialization (measured by Sm and Lloyd's indices) was very high and did not differ between flower and foliage communities, suggesting that each newly-sampled microhabitat has a large additive effect on total species richness. In accordance with previous studies, host specificity of foliage-inhabiting beetles was most pronounced among herbivorous families (Curculionidae, Chrysomelidae). By contrast, host specificity among flower-visitors was equally high among herbivorous and nonherbivorous families (e.g. Nitidulidae, Staphylinidae, Cleridae). Effective specialization (FT) measures showed that traditional correction factors used to project total species richness in nonherbivorous groups fail to fully capture diversity in the flower-visiting beetle fauna. These results demonstrate that host specialization is not concentrated within folivores as previously assumed. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 215–228.