Tympanum fluctuating asymmetry, body size and mate choice in female midwife toads (Alytes obstetricans)

We address whether fluctuating asymmetry (FA) in an external ear element is correlated with the accuracy of location of a sound source (synthetic male advertisement calls) by female midwife toads (Alytes obstetricans). Fluctu ating asymmetry in the tympanum was measured in gravid females. We studied the relationship between FA, snout-vent-length (SVL), and precision in appr oaching an acoustic stimulus through playback tests. Female mass was negati vely correlated with jump length. Tympanum FA was negatively correlated wit h the accuracy of location of a sound source. Thus, FA can play an importan t role in sexual selection by conferring an advantage in access to availabl e males by females with low values of asymmetry.