Genetic variation in laboratory and field populations of the midge, Chironomus tentans fab.: Implications for toxicology

Chironomus tentans larvae are used extensively in toxicoiogical bioassays. Gel electrophoresis was performed on seven laboratory populations and a wild population of C. tentans. Direct count heterozygosity was significantly different between wild and laboratory populations, as well as among laboratory populations. Percent polymorphic loci demonstrated the same trends but were marginally nonsignificant. The wild midge population had seven unique alleles and a significantly higher level of heterozygosity. Despite these differences the wild population was genetically similar to laboratory populations. The impact of significant differences in Chironomus genetic variability on toxicoiogical bioassays is discussed.