The evolution of parental care in the context of sexual selection

A critical reassessment of parental investment theory

Michael J. Wade, Stephen M. Shuster

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)285-292
Number of pages8
JournalAmerican Naturalist
Volume160
Issue number3
DOIs
StatePublished - Sep 2002
Externally publishedYes

Fingerprint

parental investment
parental care
sexual selection
evolutionarily stable strategy
gender differences
paternal care
fitness
paternal effect
maternal care
parental behavior
mating success
gamete
ova
mating behavior
sperm
genetic correlation
germ cells
viability
energetics
spermatozoa

Keywords

  • Anisogamy
  • Offspring desertion
  • Parental care
  • Sex ratio
  • Sexual selection

ASJC Scopus subject areas

  • Ecology

Cite this

The evolution of parental care in the context of sexual selection : A critical reassessment of parental investment theory. / Wade, Michael J.; Shuster, Stephen M.

In: American Naturalist, Vol. 160, No. 3, 09.2002, p. 285-292.

Research output: Contribution to journalArticle

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