Unravelling the relationships between life history, behaviour and condition
The hypothesis of pace-of-life syndromes (POLS) predicts relationships between traits including life history traits and risk-taking behaviour that can be mediated by the trade-off between current and future reproductive value. However, alternative causal mechanisms may also generate covariance among these traits without trade-offs. We investigated the relationships between survival to the next year, current reproductive investment and risk-taking behaviour (flight initiation distance) in male collared flycatchers, Ficedula albicollis using long-term data. We used structural equation modelling (SEM) to uncover whether the associations among traits are mediated by a common latent factor that determines how individuals balance the trade-off between current and future reproductive value. As trade-offs could be concealed when there are differences in resource acquisition between individuals, we also included potential causes of these differences, body mass and body size, in the analysis. We found that risk-taking behaviour was positively related to reproductive investment, and negatively to survival to the next year as could be predicted if investment into a risky behaviour is traded against future prospects. However, the most supported SEM model also suggested that survival to the next year was positively related to current reproductive investment, contrary to predictions of a hypothesis based on trade-off. These results remained qualitatively similar when controlling for body condition. In conclusion, we only could derive partial support for the POLS hypothesis. We suggest that aspects of individual quality, and not only trade-offs, should also be considered when interpreting the relationships between life history and behavioural traits.
Jablonszky M., Szász E., Krenhardt K., Markó G., Hegyi G., Herényi M., Laczi M., Nagy G., Rosivall B., Szöllősi E., Török J., Garamszegi L.Z. 2017. Unravelling the relationships between life history, behaviour and condition under the POLS concept using long-term data from a wild bird. Behavioral Ecolology and Sociobiology, special issue “Towards a general theory of the pace-of-life syndrome”, 72:(52)1-13