Components of fitness and the pgi polymorphism in the freshwater isopod asellus aquaticus (L). 1. fecundity selection

Abstract

Differences in reproductive output were studied between genotypes in a population of the isopod Asellus aquaticus polymorphic at the PGI locus. Reproductive output was measured both in terms of the numbers of eggs and the number of offspring per female. Significant differences were found between the three most common genotypes (3/3, 2/3, 3/4) for both measures. 3/3 had the highest reproductive output. Relative to this the output of 2/3 was 65 per cent and of 3/4 only 40 per cent. This pattern was repeated in three separate years. © 1987 The Genetical Society of Great Britain.