Ornaments or offspring: costs to reproductive success restrict sexual selection processes |
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Authors: | SUSAN FITZPATRICK ERS BERGLUND GUNILLA ROSENQVIST |
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Institution: | School of Applied Biological and Chemical Sciences, University of Ulster atjordanstown, Newtownabbey, Co. Antrim, BT37 OQB, Northern Ireland;Department of Zoology, University of Uppsala, Villav. 9, S-752 36 Uppsala, Sweden;Department of Zoology, University ofTrondheim, N-7055 Dragvoll, Norway |
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Abstract: | If, in their partner choice, males seek direct benefits (fecund females), the result will be selection for traits indicating female quality rather than for arbitrary (Fisherian) traits. However, the costs of developing and maintaining the sexually selected traits (ornaments) may reduce the resources available to the female for allocation to reproduction and hence result in lower reproductive success per brood. This hitherto unrecognized fecundity cost of sexually selected traits will constrain both the potency of sexual selection mechanisms and the degree of elaboration of sexually selected traits in females, and can also apply to males which invest in their offspring: sexual selection becomes self-limiting. The fitness implications of these costs are examined for both sexes in a variety of mating and parental care patterns. Sexual selection acting on both sexes may lead to either dimorphism or monomorphism, the latter being the case when the quality indicators chosen by both sexes coincide. Ways of evasion or reduction of these reproductive costs of allocations to sexually selected traits include using different resource components for the ornament and for reproduction, or partitioning the two allocations in time. |
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Keywords: | mate choice sex-role reversal allocation theory -ornament dimorphism Fisher process cost of reproduction condition indicators -handicap |
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