Is male plumage reflectance correlated with paternal care in bluethroats?

Although it is now well established that the conspicuous male plumage color s of many birds hal-e been subject to sexual selection by female choice, it is still debated whether females mate with colorful males to obtaiI1 direc t or indirect benefits. In species where males provide substantial parental care, females may obtain direct benefits from mating with the males that a re best at providing care. The good parent hypothesis suggests that male pl umage coloration signals a male's ability to provide parental care. Alterna tively, the differential-allocation hypothesis suggests that colorful males reduce their care in response to increased investment by females mated to attractive males. We tested these hypotheses on the bluethroat (Luscinia s. suecica), a socially monogamous, sexually dichromatic bird, in which males have a colorful throat patch consisting of a structurally derived blue are a surrounding a melanin-based chestnut spot. Male plumage coloration was ob jectively quantified by use of reflectance spectrometry. We found no eviden ce of a relationship between male coloration of either the blue patch or th e chestnut spot and the level of paternal care. Nor were there any correlat ions between male coloration and body size or body condition. Thus, our stu dy does not support the hypothesis that male coloration signals male parent al quality (the good parent hypothesis) or the hypothesis that colorful mal es reduce their care in response to increased investment by females (the di fferential-allocation hypothesis).