The Number of Species of Insect Associated with Various Trees

It is common knowledge amongst ecologists and collectors that some trees have many species of insect denizen and others, usually recently introduced, comparatively few. But the number of species of insect associated with a certain tree would seem to reflect not only the actual time it has been present in Britain but also, and of rather more importance, its general abundance or scarcity throughout this period. If this hypothesis is correct, then in other parts of the world where the pattern of tree dominance is different from that in Britain, we should expect the comparative numbers of insect species to vary accordingly. The coniferous forest belt is far more extensive in Russia than in Britain and thus pine, spruce, larch and fir (the last three introduced species in Britain) will be comparatively