ALLOZYME DIVERSITY IN SLUGS OF THE CARINARION COMPLEX (MOLLUSCA, PULMONATA)

Previous allozyme analyses of the hermaphroditic terrestrial slugs Ari on fasciatus, A. cir curcumscriptus and A, silvaticus (subgenus Carina rion) have suggested that in North America these species are each sing le monomorphic strains. However, new data on 18 putative enzyme loci s how that in western Europe the three taxa, respectively, consist of at least three, two and 12 homozygous multilocus genotypes (strains), wh ich regularly co-occur. The current opinion that American and European Carinarion populations are similarly structured, and that colonizatio n events did not affect the population genetics of North American Cari narion, should therefore be readdressed. The present data also provide the first indication of heterozygosity and possible outcrossing in Ca rinarion. Nevertheless, uniparental reproduction is confirmed as the m ain breeding system in West European Carinarion, although the high inc idence of multistrain populations in A. silvaticus and A. fasciatus ap pears at variance with the current model of population genetic structu ring in selfing terrestrial pulmonates. Finally, the systematic status of the three Carinarion spp. is tentatively questioned.