Colour polymorphism and genetic strains in Arion intermedius from Flores, Azores (Mollusca: Pulmonata)

Thirty specimens of Arion intermedins from Flores (and Corvo) were electrophoretically (PAGE) assayed for 11 enzymes, yielding information about 14 putative loci in two colour morphs of this species. One of these colour variants was tentatively identified as A. pascalianus (P morph). Except for the Mdh locus, all loci in A. intermedins sensu lato from Flores were monomorphic. Mdh, however, was diallelic for Mdh100 and Mdh122. This latter electromorph was absent in A. intermedins sensu stricto from Flores, but present in the P morph and A. intermedins from Belgium. As a consequence A. intermedins sensu lato from Flores consists of two genetic strains defined by the Mdh alleles. The genetic identity between these strains (7) is 0.929. The genetic identity between the P morph and A. intermedins sensu stricto in Flores is 0.951, while between the P morph and Belgian A. intermedins it is 0.973. These values suggest that the supposed A. pascalianus from Flores is only a colour morph of A. intermedins. This paper also provides the first published record of this species from the island of Corvo.