Biased Learning of Sexual Signals by Female Bengalese Finches

Abstract Peak shift in mate preference learning can be a driver of rapid repeated speciation. Therefore, clades that have undergone recent adaptive radiations are predicted to show biased learning of signals from the opposite sex. The estrildid finches are one such clade. In species including the Zebra Finch Taeniopygia guttata and the Bengalese Finch Lonchura striata var. domestica, females choose mates in part based on their songs. Consistent with theory, female Zebra Finches show peak shift in their learned response to male song characteristics. We used operant conditioning to train female Bengalese Finches to respond to songs with trills of one length and to ignore songs with trills of another length. Then, we exposed those females to songs with a range of trill lengths, and we observed their responses. We found that at least some Bengalese Finches also show behaviour consistent with peak shift in their response to male songs. Moreover, females evaluated songs relative to other songs they had recently heard. Our results suggest that females respond to male sexual signals with bias in multiple species in the rapidly speciating estrildid clade.