Insect Flight and Distribution

Abstract

THE pattern of tne geographical distribution of insects is very varied; but among the widely distributed specie we can recognize easily two types. First,the species which develops many local or geographical race's, such as the swallow-tail butterfly (papilio machaon)and the apollo butterfly (Par-nasstus apollo)in Europe; and secondly, the species which has little or no geographical variation over very large areas, such as certain locusts or the painted-lady butterfly (Pyrameis cardui). This latter type of distribution indicates a population within the area of which there are few natural barriers, and within which there is a continual mixing of individuals. It is associated with species which have great powers of movement ; and this movement can be either active and deliberate, as in the migration of locusts, or passive, due to distribution by air currents, as in the Aphidse and other small insects. By either of these methods, large numbers of individuals can move hundreds of miles.