Abstract-An investigation of the genetic structure of the Aporrectodea caliginosa -A. trapezoids diploidpolyploid complex of earthworms found in the Ukraine is performed by means of biochemical genetic marking with respect to six loci (Aat, Es-1, -2, -3, and -4, and Mdh) and karyotyping. All 646 individuals from 21 samples are analyzed at the biochemical gene level and karyotype samples are obtained from 70 specimens. As a result, diploid amphimictic A. caliginosa individuals (2n = 36), which form panmictic populations, and triploid (2n = 54) A. trapezoides individuals, represented by 19 hypothetical clones discovered in the course of an analysis of 157 specimens, are clearly differentiated. A clear trend towards dominance of the triploid forms in the steppe zone of Ukraine is discovered. Here they represent roughly 70% as against 12% of all A. (superspecies) caliginosa individuals in the northern forest regions. Based on the stated nature of the heterozygosity of the loci studied and the behavior of the chromosomes in meiosis, it may be claimed that the cloned forms are allotriploids, formed as a result of hybridization of a series of related forms, which, judging from the allelic pools, does not include amphimictic species that now inhabit the territory of Ukraine. That is, either the apomictic clones of A. trapezoides lack a local origin and their appearance among the fauna of Ukraine is a consequence of settlement in arid steppe regions that are unfavorable for earthworms or, on the other hand, amphimictic A. caliginosa is an invasive species.

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The existence on the territory of Ukraine of two sympatric widespread species definitely different by their chromosome number was proved based on the meiotic chromosome preparations. Besides the nominal species Pontastacus leptodactylus (Dana, 1852) with modal haploid chromosome number n = 93 we prove the existence of P. angulosus (Rathke, 1837) with n = 88.

Four chromosomal races (2n=36, 3n=54, 6n=108, 8n=144) and 96 clones have been revealed among 224 specimens of the earthworm Aporrectodea rosea over the territory of Ukraine by means of karyological analysis and biochemical genetic marking. Each population has been showed by several clones at least; moreover the clones from different places have never been identical. The clones in the range of one population can be identified with the set of quantitative and qualitative parameters.

Abstract. Kariological investigation of the earthworm Octodrilus transpadanus (Rosa, 1884) in the Ukraine showed that this species is represented by at least three races of different ploidy with the basic chromosome number n=15. Strict geographic heterogeneity of electrophoretic spectra of different populations was registered: south-eastern populations (7n=105) are characterized by a clonal structure, whereas western (from 3n = 45 to 4n = 60) and south-western (2n=30) ones have a high level of polymorphism. The Crimea sample (4n=60) is well isolated, has no clonal structure and is characterized by a series of specifi c alleles , which are absent in forms from continental Ukraine. All the forms turned out to be well isolated morphologically, except for the clonal forms, which are very much alike.