Self and cross-fertilization in Australorbis glabratus

Abstract

A single specimen of A. glabratus grown in isolation is able to reproduce quite well by self-fertilization. If it joins another conspecific individual, however, it reproduces exclusively by cross-fertilization. The possibility of a single specimen being able to give rise to a population may explain the occurrence of some colonies of planorbids showing particular characteristics and rather little individual variation, besides denoting that after treatment with planorbicides a single surviving specimen will be able to restore the population. By using the factor of albinism as genetic marker in crossing experiments, in F[1] generation a distinction can be easily made between the specimens obtained through cross- and self-fertilization. The use of albino snails in genetical experimentation applied to systematics will contribute to the biological recognition of species, thus reinforcing the morphological criterion.