There are over 2,500 species of moth in Britain counting migrants, 900 (generally larger) macro-moths and 1,600 micro-moths. This distinction is based more on taxonomic affiliation than on size. In the last 40 years the total abundance of larger moths in southern Britain has decreased by about 40%, largely due to the loss of habitat. The overall decrease is comparable to declines in butterflies and bees, and probably reflects similar trends in other insects. Some moth larvae are pests, eating leaves or boring into shoots and fruit.