CYTOGENETIC DIFFERENTIATION OF NATURAL AN D LABORATORY POPULATIONS OFCAMPTOCHIRONOMUS TENTANS (FABRICIUS) (CHIRONOMIDAE, DIPTERA)

Chromosomal polymorphism and cytogenetic differentiation of 28 natural and laboratory populations of Camptochironomus tentans from Siberia, Europe, and North America were examined. Interpopulation variation of the number and frequency of inversion sequences and mean heterozygosit y in C. tentans populations from different continents were shown to be similar. In inversion sequence composition, Siberian and European pop ulations were similar to each other but different from North American ones. The number of inversion sequences in Siberian and European popul ations [45] was much higher than that in populations from North Americ a [23]. The cytogenetic distance between C. tentans populations from N orth America and those from Europe and Siberia (D-N = 1.637 and D-N = 1.650, respectively) significantly exceeds that between populations wi thin each of the continents (in North America, D-N = 0.313; in Europe, D-N = 0.176; and in Siberia, D-N = 0.111). Cytogenetic differentiatio n of population's from Eurasia and America is higher than interpopulat ional differences.