REPRODUCTIVE CHARACTER DISPLACEMENT OF FEMALE MATE CHOICE IN THE GRAY TREEFROG, HYLA-CHRYSOSCELIS

Females of the grey treefrog, Hyla chrysoscelis, from three areas where a genetically incompatible, sibling species, H. versicolor, also occurred, were much more likely to prefer synthetic sounds with fine-temporal properties typical of conspecific males than were females from two areas of remote allopatry. Specifically, more than 90% of the females from sympatric populations weighted a species-specific cue (pulse-repetition rate = pulse rate) more strongly than they did a cue (call duration) that mediates intraspecific mate choice, whereas only about 50% of the females from remote allopatric populations did so. These results suggest that selection for the avoidance of mating mistakes has acted on females in sympatric populations. If this is a general phenomenon, then the apparent rarity of reproductive character displacement may be explained at least in part by the fact that nearly all previous studies have focused solely on geographical patterns of variation in male courtship signals. © 1994 The Association for the Study of Animal Behaviour.