GENETIC-VARIATION IN MALE SONG AND FEMALE SONG PREFERENCE IN THE GRASSHOPPER CHORTHIPPUS-BRUNNEUS (ORTHOPTERA, ACRIDIDAE)

Males of Chorthippus brunneus, the common field grasshopper, produce a species-specific song during courtship to which receptive females may respond by stridulation. The signal and the preference for the signal are part of a sexual signal-receiver system which must be co-adapted if males and females are to recognize each other. Evolution of this system will depend on the extent of genetic variation in male and female components and their genetic control. Two experiments using divergent artificial selection were performed to test for the presence of genetic variation in the male signal (mean syllable length of the calling song) and in female preference for that signal. Two generations of selection were performed on male mean syllable length. A response occurred after only one generation of selection, resulting in a significant difference between the two divergent lines. Similarly, selection on female acoustic preference for mean syllable length, tested using artificially created calling songs, resulted in an immediate and significant response to selection. The difference between the lines declined somewhat in later generations. © 1994 The Association for the Study of Animal Behaviour.