TY - JOUR
T1 - Divorce and infidelity are associated with skewed adult sex ratios in birds
AU - Liker, Andras
AU - Freckleton, Robert P.
AU - Székely, Tamas
PY - 2014/4
Y1 - 2014/4
N2 - Adult sex ratio (ASR) is a fundamental concept in population demography, and recent theory suggests that ASR plays a central role in social behavior, mating systems, and parental care [1-6]. Unbalanced ASRs are predicted to influence pair-bond and mating behavior, since the rarer sex in the population has more potential partners to mate with than the more common sex [1, 4]. Here we use phylogenetic comparative analyses to test whether ASR is related to three major aspects of mating behavior: divorce, social polygamy, and pair-bond infidelity. ASR is strongly correlated with long-term pair bonds, since the divorce rate is higher in species with a female-biased sex ratio, indicating that mate change by pair members and/or breaking of pair bonds by unmated individuals is more frequent when females outnumber males. Short-term pair bonds are also associated with unbalanced ASRs: males are more commonly polygamous when females outnumber males, and conversely, females are more polygamous when males outnumber females. Furthermore, infidelity increases with male-biased ASR in socially monogamous birds, suggesting that male coercion and/or female willingness to cheat the partner are facilitated by male-biased ASR. Our results provide the first comprehensive support for the proposition that ASR influences multiple aspects of pair-bond and mating behavior in wild populations.
AB - Adult sex ratio (ASR) is a fundamental concept in population demography, and recent theory suggests that ASR plays a central role in social behavior, mating systems, and parental care [1-6]. Unbalanced ASRs are predicted to influence pair-bond and mating behavior, since the rarer sex in the population has more potential partners to mate with than the more common sex [1, 4]. Here we use phylogenetic comparative analyses to test whether ASR is related to three major aspects of mating behavior: divorce, social polygamy, and pair-bond infidelity. ASR is strongly correlated with long-term pair bonds, since the divorce rate is higher in species with a female-biased sex ratio, indicating that mate change by pair members and/or breaking of pair bonds by unmated individuals is more frequent when females outnumber males. Short-term pair bonds are also associated with unbalanced ASRs: males are more commonly polygamous when females outnumber males, and conversely, females are more polygamous when males outnumber females. Furthermore, infidelity increases with male-biased ASR in socially monogamous birds, suggesting that male coercion and/or female willingness to cheat the partner are facilitated by male-biased ASR. Our results provide the first comprehensive support for the proposition that ASR influences multiple aspects of pair-bond and mating behavior in wild populations.
UR - http://www.scopus.com/inward/record.url?scp=84896104002&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1016/j.cub.2014.02.059
U2 - 10.1016/j.cub.2014.02.059
DO - 10.1016/j.cub.2014.02.059
M3 - Article
SN - 0960-9822
VL - 24
SP - 880
EP - 884
JO - Current Biology
JF - Current Biology
IS - 8
ER -