Letters to Nature

Nature 416, 841-844 (25 April 2002) | doi:10.1038/416841a; Received 6 September 2001; Accepted 12 January 2002

Low host specificity of herbivorous insects in a tropical forest

Vojtech Novotny1, Yves Basset2, Scott E. Miller3, George D. Weiblen4, Birgitta Bremer5, Lukas Cizek1 & Pavel Drozd6

  1. Institute of Entomology, Czech Academy of Sciences and Biological Faculty, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic
  2. Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Ancon, Panama
  3. Department of Systematic Biology, National Museum of Natural History, Smithsonian Institution, Washington DC 20560-0105, USA
  4. Department of Plant Biology, University of Minnesota, 220 Biological Sciences Center, 1445 Gortner Avenue, St Paul, Minnesota 55108-1095, USA
  5. Bergius Foundation at the Royal Swedish Academy of Sciences, PO Box 50017, SE-104 05 Stockholm, Sweden
  6. University of Ostrava, Department of Biology, 30. dubna 22, 701 03 Ostrava, Czech Republic

Correspondence to: Vojtech Novotny1 Correspondence and requests for materials should be addressed to V.N. (e-mail: Email: novotny@entu.cas.cz).

Two decades of research1, 2, 3, 4 have not established whether tropical insect herbivores are dominated by specialists or generalists. This impedes our understanding of species coexistence in diverse rainforest communities. Host specificity and species richness of tropical insects are also key parameters in mapping global patterns of biodiversity1, 4, 5. Here we analyse data for over 900 herbivorous species feeding on 51 plant species in New Guinea and show that most herbivorous species feed on several closely related plant species. Because species-rich genera are dominant in tropical floras, monophagous herbivores are probably rare in tropical forests. Furthermore, even between phylogenetically distant hosts, herbivore communities typically shared a third of their species. These results do not support the classical view that the coexistence of herbivorous species in the tropics is a consequence of finely divided plant resources; non-equilibrium models of tropical diversity6 should instead be considered. Low host specificity of tropical herbivores reduces global estimates of arthropod diversity from 31 million (ref. 1) to 4–6 million species. This finding agrees with estimates based on taxonomic collections, reconciling an order of magnitude discrepancy between extrapolations of global diversity based on ecological samples of tropical communities with those based on sampling regional faunas7, 8.