DIFFERENCES IN PREFERENCE FOR SPECIES-SPECIFIC FEMALE CALLS BETWEEN ACOUSTICALLY EXPERIENCED AND ACOUSTICALLY NAIVE MALE RIBAUTODELPHAX PLANTHOPPERS (HOMOPTERA, DELPHACIDAE)

Males of the planthopper Ribautodelphax imitans were exposed to playba cks of either conspecific or heterospecific (R. imitantoides) female c alls during their development from egg to adult, and thereafter these, as well as naive males, were offered a two-way choice between these c alls. Males of all treatments approached the conspecific call signific antly more often. However, males primed by the conspecific call chose the heterospecific call almost four times less often than did males pr imed by heterospecific calls or naive males, thus showing that the pre ference for conspecific calls can be partly ''learned. '' Males primed by heterospecific calls performed very similarly to completely naive males, suggesting that the signal recognition mechanism is much less s ensitive to heterospecific calls than to conspecific calls. Males with experience of the conspecific female call tended to take more time to reach the call source in the trials than both other types of males. T he evolutionary implications of these findings are discussed.