The recruitment sweepstakes has many winners: Genetic evidence from the sea urchin Strongylocentrotus purpuratus

Jonathan M. Flowers, Stephen C. Schroeter, Ronald S. Burton

Research output: Contribution to journalArticle

Abstract

As a consequence of free spawning in the unpredictable nearshore environment, marine species with large fecundities and high pre-reproductive mortality may be subject to extreme variance in reproductive success. If the unpredictability of the ocean results in only a small subset of the adult population contributing to each larval cohort, then reproduction may be viewed as a sweepstakes, with chance events determining which adults are successful each spawning season. Such a reproductive sweepstakes scenario may partially account for large reductions in effective population sizes relative to census population sizes in marine species. We evaluated two predictions of the sweepstakes reproductive success hypothesis by testing: (1) whether sea urchin recruits contain reduced genetic variation relative to the adult population; and (2) whether cohorts of sea urchin recruits are genetically differentiated. Mitochondrial DNA sequences were collected from 283 recently settled Strongylocentrotus purpuratus recruits from four annual cohorts spanning seven years in locations throughout California. Observed haplotype numbers and haplotype diversities showed little evidence of reduced genetic variation in the recruits relative to the diversity estimated from a previously reported sample of 145 S. purpuratus adults. Different cohorts of recruits were in some cases mildly differentiated from each other. A computer simulation of sweepstakes recruitment indicates that our sampling strategy had sufficient statistical power to detect large variances in reproductive success.

Original languageEnglish (US)
Pages (from-to)1445-1453
Number of pages9
JournalEvolution
Volume56
Issue number7
DOIs
StatePublished - 2002

Keywords

  • Bet hedging
  • Cytochrome oxidase I
  • Dispersal
  • Effective population size
  • Gene flow
  • Genetic drift
  • Reproductive success

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Agricultural and Biological Sciences(all)

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