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Birds of Paradise demonstrate the Handicap Principle

The theory[]

The handicap principle was introduced in 1975 by Amotz Zahavi. Zahavi (1975) was a biologist who suggested the principle to explain the role of  sexual ornamentation (or biological ornamentation)  within sexual selection. Ornamentation is considered costly to produce (Badyaev, 2004). And in order for ornamentation to be effective it must be costly to possess and thereby demonstrate that the individual can expend the extra energy and effort to support it (Massaro, Davis & Darby, 2003). 

Zahavi (1975) wrote, "it is possible to consider the handicap as a kind of a test imposed on the individual. An individual with a well developed sexually selected character, is an individual which has survived a test” (p. 207). By surviving this test the individual is demonstrating superior genes. 

Examples of the Handicap Principle[]

Long-Legged Flies: The female of this species has been found to select mates who demonstrate "directional asymmetry" and who posses a left wing that is both a different shape and also larger than the right wing (Justin & Richard, 2004). Justin & Richard (2004) proposed that this selection could be attributed to the Handicap Principle. In order to survive with this severe "handicap" the male who possess this feature must have "genetic superiority" (Justin & Richard, 2004). 


The extensive tail-feathers of this peacock support the Handicap Principle

Yellow-Eyed Penguin (Megadyptes antipodes):  This species will select to mate with individuals who possess the costly caratenoid-derived ornamentation which is expressed in the plumage around the eye and head (Massaro et al, 2003). Massaro et al (2003) write that "potentially female and male yellow-eyed penguins could use eye and plumage coloration as an indirect cue in assessing age and quality of individual birds during mate choice." 

Other examples include the peacock who faces additional predation pressure due to his cumbersome tail and Birds of Paradise who attract predators' attention due to their bright plumage (Zahavi, 1975)


Badyaev, A.V. (2004) Developmental perspective on the evolution of sexual ornaments. Evolutionary Ecology Research, 975-991. 

Freeman, S. & Herron, J. (2007). Evolutionary Analysis 4th Ed. Sexual Selection, pp 401-441. 

Justin B., R., & Richard L., H. (2004). A new genus of long-legged flies displaying remarkable wing directional asymmetry. Proceedings Of The Royal Society B: Biological Sciences271S114-S116.

Massaro, M., Davis, L. S., & Darby, J. T. (2003). Carotenoid-derived ornaments reflect parental quality in male and female yellow-eyed penguins (Megadyptes antipodes). Behavioral Ecology & Sociobiology55(2), 169-175. 

Zahavi, A. (1975). Mate selection-a selection for a handicap. Journal Of Theoretical Biology53(1), 205-214.