Fluctuating asymmetry in the redcollared widow : testing theories of sexual selection.
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Date
1997
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Abstract
Sexual selection is usually invoked to explain the evolution of elaborate
epigamic characters in animals. However, the mechanism by which female
choice operates is poorly understood, and it is not clear whether female
choice is purely aesthetic or related to male genotypic quality. It has been
suggested that Moller's fluctuating asymmetry (FA) hypothesis may resolve
the 'arbitrary trait'-'good gene' debate. However, tests of this controversial
hypothesis have yielded equivocal results. I examined the allometric patterns
of FA in the redcollared widow in order to test the FA hypothesis. In addition, I
documented intrapopulation variation in trait size to determine whether
females could distinguish between males on the basis of ornament size
and/or symmetry.
Male tail length was found to be more variable in size than other traits,
suggesting that sufficient variation exists in ornament size for females to
distinguish between males on this basis. In addition, the prediction of the FA
hypothesis that ornaments would display higher degrees of asymmetry than
non-ornamental traits was supported. However, no significant linear or
second-order polynomial relationship was found between trait size and
asymmetry for tail, wing and tarsus length. Furthermore, neither tail length or
symmetry was correlated with indices of body condition.
Although this might suggest that the FA hypothesis is invalid, I argue
that the assumptions of the hypothesis are too simplistic for it to hold true for
all species without taking the basic biology of the species into account.
Description
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.
Keywords
Euplectes ardens--Behaviour., Sexual selection in animals., Courtship of animals., Birds--Evolution., Theses--Zoology.