Hydrobiologia

, Volume 420, Issue 1, pp 211–219

Genetic divergence and larval dispersal in two spider crabs (Crustacea: Decapoda)

  • L. I. Weber
  • R. G. Hartnoll
  • J. P. Thorpe
Article

DOI: 10.1023/A:1003905115208

Cite this article as:
Weber, L.I., Hartnoll, R.G. & Thorpe, J.P. Hydrobiologia (2000) 420: 211. doi:10.1023/A:1003905115208

Abstract

The spider crabs Inachus dorsettensis (Pennant) and Hyas coarctatus Leach are widespread in subtidal areas of muddy sand or gravel around western Europe. Both species have a life cycle with an obligatory planktonic larval phase of several weeks, which might be expected to cause widespread larval dispersal and consequent genetic homogeneity over considerable distances. However, earlier work on both taxa has indicated differences in growth pattern between populations separated by tens of kilometres. This study was undertaken to determine whether these differences were purely environmental or whether, despite the short distances involved, differences may have a genetic basis. A study of gene frequencies, as indicated by allozymes in samples of adults collected off the Isle of Man (northern Irish Sea), indicates significant genetic differentiation between populations over a geographical distance of only about 40 km in both Inachus dorsettensis (θ = 0.086 ± 0.048) and Hyas coarctatus (θ = 0.023 ± 0.017). Variability measures differed between species, showing I. dorsettensis to have a mean number of alleles per locus of 2.5–2.6 and a range of gene diversity of 0.216–0.241, while H. coarctatus showed lower values of mean number of alleles (1.9–2.0) and a range of gene diversity from 0.122 to 0.124. Given the high expected larval mobility of the two species the results are most surprising. Possible explanations are discussed in relation to population discontinuities and patterns of larval drift.

Crustacea Majidae allozymes gene flow larval dispersal Inachus Hyas 

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • L. I. Weber
    • 1
  • R. G. Hartnoll
    • 1
  • J. P. Thorpe
    • 1
  1. 1.School of Biological SciencesThe University of Liverpool, Port Erin Marine LaboratoryPort Erin, Isle of ManU.K.
  2. 2.Dpto, FisiologiaFundação Universidade Federal do Rio GrandeRio Grande, RSBrazil

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