The evolution of paternity and paternal care in birds

Abstract

Paternity has been hypothesized to be related to the evolution of paternal care because (1) there should be selection for males not to invest in broods with an uncertain parentage, or (2) male extrapair activity is traded against paternal care. We used interspecific comparisons to discriminate between these alternatives. Male participation in three kinds of parental care (nest building, incubation, provisioning of offspring) increased with high paternity in their own nests. Male parental activities at some stages of the breeding cycle were significantly correlated. A multivariate analysis taking this intercorrelation between different components of care and potentially confounding variables such as precociality, polyandry, and sexual dichromatism into account revealed that paternity was significantly positively related to offspring provisioning, while male participation in the other components of parental care did not explain a significant amount of interspecific variation in paternity. Analyses of evolutionary transitions between different dichotomized states of paternity and paternal care provided no clear conclusions concerning evolutionary scenarios. However, theoretical arguments and the results of the contrast analyses suggest that male provisioning of offspring evolved in response to paternity.