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The genetic effects of competition in seaweed flies
Article first published online: 14 JAN 2008
Biological Journal of the Linnean Society
Volume 57, Issue 1, pages 1–11, January 1996
How to Cite
Leggett, M.C., Wilcockson, R.W., Day, T.H., Phillips, D.S. and Arthur, W. (1996), The genetic effects of competition in seaweed flies. Biological Journal of the Linnean Society, 57: 1–11. doi: 10.1111/j.1095-8312.1996.tb01692.x
- Issue published online: 14 JAN 2008
- Article first published online: 14 JAN 2008
- Received 2 December 1994, accepted for publication 24 February 1995
- differential survival;
- Coelopa frigida;
- Coelopa pilipes.
In spite of abundant evidence that intra- and inter-specific competition occurs in natural communities, there is surprisingly little to suggest it is a major force promoting genetic change. This report assesses the genetic effects of competition in two species of seaweed fly, Coelopa frigida and C. pilipes. In laboratory cultures of C. frigida the relative survival of heterozygotes at the Adh locus, which was being used as a marker for the large αβ chromosomal inversion, was greater than that of homozygotes. In monocultures of C. frigida this competitive superiority was dependent on larval density. At low densities facilitation was seen, whereas at high larval densities there was competition. In mixed cultures of the two species, interspecific competition contributed to the differential mortality of C. frigida, and observations of natural populations suggested that competition may have similar effects to those described in laboratory culture. A possible mechanism involving the supply of nutritive microorganisms is proposed to underly both intra- and inter-specific competition. In seaweed flies, competition and the consequent differential mortality appear to be forces maintaining rather than reducing genetic variation.