CHROMOSOMAL-POLYMORPHISM IN A CHIRONOMUS-PLUMOSUS (L) (DIPTERA, CHIRONOMIDAE) POPULATION FROM A FISH POND IN SOUTHERN BOHEMIA - A LONG-TERM STUDY

The chromosomal polymorphism in a Chironomus plumosus (L.) population from a fish pond was investigated during a period of six years. Polymorphism including two types of homozygous paracentric inversions and their heterozygote combination was found in chromosome arms A, B, and C. The polymorphism in arm B was found to be unstable; a shift in the frequencies of the inversions was observed during the six-year period. Compared to the Hardy-Weinberg expectations, a significant deficit of heterozygotes was observed in the arm B.