The insects of British trees: Community equilibration in ecological time

The most widely accepted model of insect-plant interaction derives from the correlation between insect species richness and the relative number of recorded Quaternary fossil remains of British tree species (Southwood, 1961). The implications of this relationship are: that community formation and the equilibration of insect species richness is a very slow process, taking at least 2 million years, that introduced plant species will necessarily have relatively few associated insect species, that insect communities are basically different from vertebrate communities in that saturation of species does not occur (Whittaker, 1969). I present a model mutually exclusive to Southwood's, indicating that insects of British trees follow a species area relationship. The implications of this new finding are: insect community formation and equilibration of species richness occurs at least within 300 years, the insect diversity of introduced plants becomes a function mainly of the range of distribution of the plant within ecological time, insect communities do not differ from vertebrate communities in terms of species saturation rate. The saturation occurs within ecological time for both groups