GENETIC AND MORPHOLOGICAL VARIATION IN THE PARTHENOGENETIC EARTHWORM EISENIELLA-TETRAEDRA (SAV) (OLIGOCHAETA, LUMBRICIDAE) FROM SOUTH FINLAND AND NORTH NORWAY

Sixteen overall enzyme phenotypes (clones) were identified in 179 Eise niella tetraedra individuals from southern Finland and from northern N orway about 1200 km to the north. The common clones were unevenly dist ributed between the localities. The two most frequent clones A and B w ere recorded both in the north and in the south. Using these as norm c lones, comparisons showed that the clones in N Norway deviated on aver age less from clone A than from clone B. The opposite was true for the clones in S Finland. Diversity of clones in the pooled Norwegian samp le was higher than in the corresponding Finnish sample. Similarity of clones was greater within northern and within southern than between no rthern and southern localities. E. tetraedra is tetraploid (4n = 72) i n the study area. Polyploidy and the pattern of clonal variation indic ate that it is also parthenogenetic. Size and segment numbers in adult s varied according to locality but no clear-cut regional trend was fou nd. Male pore terminalia were present in all the adults and they usual ly located on the 13th segment. In northern worms they were more protu berant than in southern ones. Morphological variability showed no corr elation to the enzyme patterns. Even though E. tetraedra is stenotopic , in addition to being parthenogenetic and polyploid, it shows rather wide morphological and genetic diversity between populations which may be attributed to the impacts of mutations, dissimilar dispersal event s and environmental variables.