Female zebra finches prefer symmetrically banded males, but only during interactive mate choice tests

Abstract

We used a four-arm choice chamber to investigate whether the symmetry of artificial traits (leg bands) influenced how attractive male zebra finches,Taeniopygia guttata, were to females, and whether a female’s preference was influenced by the opportunity to interact with males during choice tests. Females (N=10) were tested separately and moved freely between the chamber’s arms, each of which contained a male wearing bands (two per leg) in symmetric, asymmetric or cross-asymmetric configurations. In three of the six tests experienced by each female, one-way glass (mounted diagonally within each arm) prevented males from seeing the female or their own reflection. During the other three tests, transparent glass was used, so males could see and react to the female. A male’s band combination had a significant influence on the amount of time that females spent with him, but only during transparent-glass tests, where symmetric males were preferred. The results of our transparent-glass tests were similar to those reported by Swaddle & Cuthill (1994,Nature,367, 165–166), in a study where females selected between males that were interacting with their own mirror images (reflected by one-way glass). We discuss why females display the same apparent preference when tested with males engaged in intra- (Swaddle & Cuthill’s study) versus intersexual activities (our study). Since females in our study displayed a preference only when males could interact with them, caution may be required when extrapolating the results of static choice tests (e.g. involving models, one-way glass or video images) to situations where the participants can interact.