Age-Advertisement and the Evolution of the Peacock's Train

The present article discusses the Age-Advertisement Theory in relation to the evolution of a peacock's train of feathers. In the journal article's introduction, Manning (1989) puts forth four main explanations that previous research have used to explain the evolution of such elaborate tails. The first explanation states that the sons of "choosy" females in a population with posses the "preferred type of elaborate tails and will in turn be preferred by the daughters of other "choosy" females in the population. The second explanation puts forth the Handicap principle in order to to try to illustrate the robustness and quality of a peacock's genes despite its large and inconvenient train of feathers. The third principle looks at the condition of the peacock's train of feathers that is dependent on parasite load--a large train of feathers therefore shows a low parasite load. Finally, the article introduces the Age-Advertisement Theory which states that a large train of feathers is indicative of age and overall genetic quality. In conclusion, the article was able to find a strong correlation between the age of a male peafowl and the actual number of feathers in the peacock's train (specifically the number of ocellus feathers). It was indeed concluded that this is an honest advertisement of age in peacocks.

Journal article:
          Manning J. T. (1989). Age-advertisement and the evolution of the peacock's train. Journal of Evolutionary Biology, 2, 379-384.