Species Specific Enzymes in Some Snail Species (Mollusca, Gastropoda) from Fresh and Brackish Water in Sweden

Horizontal starch gel electrophoresis was employed to reveal possible species specific patterns of esterases and peroxidases in four species of Lymnaea, Myxas glutinosa, Bithynia tentaculata, Theodoxus fluviatilis and the genus Hydrobia. From four of the species specimens from both fresh and brackish water were used. Esterase patterns were species specific in the anodic portion of the zymograms in all species. The remainder of the patterns displayed marked individual variation, the nature of which was not investigated. The peroxidases also revealed clearly species specific patterns. The amount of variation exhibited in fresh and brackish water populations of L. peregra and T. fluviatilis, the most thoroughly investigated species, was found to be roughly of the same magnitude, indicating a similar amount of intra-specific variation in fresh and brackish water. In the four Lymnaea species it appears from the peroxidase patterns that alternative alleles from an ancestral polymorphic locus have become established in different species. The esterase patterns of L. peregra and L. auricularia revealed distinct differences between the two taxa, which is also supported by the appearance of the spermathecal duct, whereas shell morphology and immunological investigations fail to show inter-taxon differences.