Abstract
Carotenoid-based colouration is common in animal ornamental traits. Although many hypotheses assume health signalisation based on these traits the underlying physiological mechanism remains unresolved.
In this article we propose a new hypothesis which assumes that under certain conditions is the maintenance of high levels of carotenoids harmful for the organism. If antioxidant reserves are low carotenoids may be easily attacked by reactive oxygen species resulting in their cleavage into toxic aldehydes.
Therefore maintanance of high levels of carotenoids represents a handicap which can be afforded only by high quality individuals. We suggest that the physiological mechanism involves testosterone effect on antioxidant reserves and carotenoid levels.
Current evidence supporting this hypothesis is given.