FACTORS RESPONSIBLE FOR INTRASPECIFIC VARIATION IN THE CALLING SONGS OF CRICKETS

Abstract

A knowledge of the intraspecific variation in cricket calling songs1 and of the factors causing these variations is fundamental to the study of other aspects of the songs. For instance, work on the behavioral significance of the calling song must take into account the changes in calling song that occur with changes in certain environmental factors. Likewise, evaluation of interspecific differences and attempts to explain their origin are dependent upon a correct understanding of intraspecific differences. Finally, one working on the nervous control of singing must know what he has to explain before he can produce a thorough explanation. The factors responsible for intraspecific variation in cricket calling songs can be classified conveniently under three headings: (1) current environment, i.e., the environment of the cricket at the time he is producing the song, (2) previous interactions with the environment, and (3) genetic factors. Each of these will be discussed in turn, but first I will describe the mechanism of sound production in crickets and the physical characteristics of cricket calling songs.