| Abstract: | Female Great Tits are known to eavesdrop on the singing behaviour of males. It is unknown, however, whether manipulation of these signals is sufficient to influence extra-pair copulations, or whether such potentially costly reproductive decisions are unaffected by altering short-term signals of condition. Using interactive playbacks, we systematically engaged males in territorial contests in which we could control whether the focal male won or lost the interaction, regardless of the males' true potential. We then determined the levels and patterns of extra-pair paternity among experimental and neighbouring pairs using DNA microsatellite analysis. Extra-pair young were found in equal frequency among the nests of males allowed to win interactions as among those who lost interactions. However, cuckolded males were significantly less variable in allele sizes across the five microsatellite alleles tested than males who were not cuckolded. As measures of genetic variability are increasingly being found to correlate with individual fitness, this may suggest that females are attentive to underlying measures of condition when making extra-pair decisions. Short-term modification of the males' perceived quality may be insufficient to cause females to alter extra-pair decisions. |
