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The evolution of parental care in the context of sexual selection: A critical reassessment of parental investment theory

Wade, Michael J. and Shuster, Stephen M. (2002) The evolution of parental care in the context of sexual selection: A critical reassessment of parental investment theory. American Naturalist, 160 (3). pp. 285-292. ISSN 1537-5323


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Publisher’s or external URL: http://dx.doi.org/10.1086/341520


Males and females are often defined by differences in their energetic investment in gametes. In most sexual species, females produce few large ova, whereas males produce many tiny sperm. This difference in initial parental investment is presumed to exert a fundamental influence on sex differences in mating and parental behavior, resulting in a taxonomic bias toward parental care in females and away from parental care in males. In this article, we reexamine the logic of this argument as well as the evolutionarily stable strategy (ESS) theory often used to substantiate it. We show that the classic ESS model, which contrasts parental care with offspring desertion, violates the necessary relationship between mean male and female fitness. When the constraint of equal male and female mean fitness is correctly incorporated into the ESS model, its results are congruent with those of evolutionary genetic theory for the evolution of genes with direct and indirect effects. Male parental care evolves whenever half the magnitude of the indirect effect of paternal care on offspring viability exceeds the direct effect of additional mating success gained by desertion. When the converse is true, desertion invades and spreads. In the absence of a genetic correlation between the sexes, the evolution of paternal care is independent of maternal care. Theories based on sex differences in gametic investment make no such specific predictions. We discuss whether inferences about the evolution of sex differences in parental care can hold if the ESS theory on which they are based contains internal contradictions.

Item Type: Article
Publisher’s Statement: © 2002. Copyright by The University of Chicago Press for The American Society of Naturalists.
ID number or DOI: 10.1086/341520
Keywords: anisogamy; Behavior; Competition; Ecology; female choice; mating systems; offspring desertion; parental care; potential reproductive rates; sex ratio; sexual selection; Vertebrates
Subjects: Q Science > QL Zoology
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > Biological Sciences
Date Deposited: 30 Sep 2015 05:29
URI: http://openknowledge.nau.edu/id/eprint/319

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