Re-interpretation of genetic variation in simocephalus (cladocera, daphniidae).

Populations of several co-existing species of Simocephalus were examined electrophoretically at 11 enzyme loci. The prevailing pattern was one of extensive allelic substitution between species and low levels of polymorphism (0-10%) within species. Genetic identity values between species were very low (10-50%). These results concur with those for other cyclic parthenogens, but are in sharp contrast to previous interpretation of data derived from populations of Simocephalus from the same sites.