The History of the Speckled Wood Butterfly (Pararge aegeria) in Scotland, with a Discussion of the Recent Changes of Range of Other British Butterflies

Abstract

At the present day the range of the speckled wood butterfly (P. aegeria) in Britain is the south and Midlands of England, Wales, and an isolated area in the west of Scotland. During the 19th century its range was virtually continuous over England, Wales, and Scotland except the extreme north. From about 1860 to 1920, this larger range was greatly reduced and was divided into 2 widely separated parts. More recently some recovery has taken place, notably in the s. of England. The hypothesis that the present-day range is due to a contraction caused by a Pleistocene glaciation is untenable. In addition to the speckled wood, 7 other British butterflies (13% of the resident fauna) have undergone great expansions or contractions of range in the past 150 yrs. It is suggested that this shows that the ranges of many butterflies alter so rapidly that discussion of their present ranges in Britain by the methods of classical zoogeography is very difficult.