MCGLOTHLIN, J. W.; GAUDIOSO, J. M.; KETTERSON, E. D.; Indiana University, Bloomington; Providence College, RI; Indiana University, Bloomington: Relationships between sexually selected traits and parental quality in dark-eyed juncos

Sexually selected traits are often related to some aspect of male quality, enabling females to choose higher-quality males as mates. In species with biparental care, elaboration of such traits may predict the quality of parental assistance a male will provide. The good parent hypothesis predicts a positive correlation between the expression of sexually selected traits and parental care, because both may be related to overall phenotypic quality. Alternatively, the differential allocation hypothesis (sensu Kokko 1998) predicts a negative relationship because attractive males benefit from spending more time seeking mates and less time caring for their own offspring. In a natural population of dark-eyed juncos (Junco hyemalis), we examined the relationships between parental care and three traits (size, plumage coloration, and age) known to be important in obtaining mates. We found that older males with whiter tails, which should be more attractive to females, fed their young less often than young males with tails that are less white. In addition, older, larger males were less likely to feed their mate during incubation. These results suggest that attractive males decrease their parental effort in order to spend more time searching for mates, which is consistent with the differential allocation hypothesis.