How many species of host-specific insects feed on a species of tropical tree?

Abstract

Receiued 3January 1995, acceptedfor publuahn I5 December I995The assumptions on the host specificity of beetles that led Terry Erwin to suggest that there may be over 30 million arthropod species were tested for 10 species of trees and their insect associates at a rainforest site in Papua New Guinea. The data included 391 species and 4696 individuals of herbivorous beetles collected during a one year period using hand collecting, beating, branch clipping, intercept Right traps and pyrethrum knockdown. Insect host specificity was assessed by feeding trials in captivity. The data suggest that between 23 and 37 monophagous leaf-feeding species are most likely to be present in this system, whereas Erwin's method yields an estimate of 138 monophagous species. The major factors responsible for the discrepancy between our observations and Erwin's assumptions appears to be (a) the importance of transient species; @) the insect fauna that is shared among tree species; (c) some generalist wood-eating species may inflate the apparent species richness of leaf-feeding beetles; and (d) the proportion of specialist species varies significantly among tree species. We conclude that studies reporting the proportion of specialist insect herbivores associated with particular tropical tree species will yield only a portion of the information needed to estimate global arthropod species richness, but may be useful for elucidating certain aspects of food-web ecology in tropical rain forests.

Endophytic fungal communities in woody perennials of three tropical forest types of the Western Ghats, southern India

“…Thus, corrections may have to be made to the final figures of species diversity to accommodate non-culturable fungi and species that might emerge by molecular searches. These points not withstanding, the wide distribution of a few culturable endophyte species transcending host taxonomic barriers as observed in the present study also, should be taken into account for any extrapolation exercise to avoid exaggerated diversity values (Basset et al 1996).…”

Quantitative estimation of insect diversity inhabitingCalotropis procerain industrial and nonindustrial areas of West Bengal, India

“…The insect species diversity from a single tropical site is often used to obtain an ecological estimate for the species diversity of a region (Erwin 1982;Basset et al 1996; Fig. 3 Principal components ordination based on insect abundance on C. procera at eight study sites (Col, Dur, and Pati are less than 6 km from Haldia.)…”

Arthropod faunas of crowns of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) in mediterranean-climate forest: A preliminary regional-scale comparison

“…That is, for comparisons of single species from these taxa, as is the case for jarrah and marri, similar amounts of leaf damage are expected. Basset et al ( 1996) suggested that host specialization was not an important determinant of herbivore diversity in floristically diverse tropical canopies although 55% of chewer insect species were considered specialists. Apparent host specialization by relatively abundant herbivorous insects may be strongly influenced by relative availablility of different hosts and their relative attractiveness or suitability (e.g.…”