Factors affecting the distribution of genetic variability in the guppy, Poecilia reticulata

P. W. Shaw*, G. R. Carvalho, A. E. Magurran, B. H. Seghersf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


Previous studies on Trinidadian guppies have shown an apparent association of genetic variability, expressed as mean heterozygosity (Ho) at allozyme loci, with river order: fish from lowland sites exhibit higher mean Ho than their upland counterparts. Detailed genetic and behavioural observations were undertaken in the present study by repeated sampling throughout two river courses to examine population heterogeneity. Results show that the predation regime mediated mating behaviour of upland and lowland populations in the wild is not as divergent as previous laboratory observations have suggested. Furthermore, genetic variation at the eight loci variable in Trinidadian populations (p100=0·13–O·88, H0=O·03–0·23) appears to bear little association with predation regime, but is related to sub‐structuring of populations by habitat features and geographic isolation. We therefore conclude that the observed patterns of genetic variability arise primarily as a consequence of stochastic as opposed to deterministic factors.

Original languageEnglish
Pages (from-to)875-888
Number of pages14
JournalJournal of Fish Biology
Issue number5
Publication statusPublished - Nov 1994


  • courtship
  • environment
  • genetic variability
  • guppy
  • heterozygosity
  • Poecilia
  • predation
  • river order


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