Data from: Handicap principle implies emergence of dimorphic ornaments

Species spanning the animal kingdom have evolved extravagant and costly
ornaments to attract mating partners. Zahavi's handicap principle
offers an elegant explanation for this: ornaments signal individual
quality, and must be costly to ensure honest signalling, making mate
selection more efficient. Here, we incorporate the assumptions of the
handicap principle into a mathematical model and show that they are
sufficient to explain the heretofore puzzling observation of bimodally
distributed ornament sizes in a variety of species.