EFFECTS OF INBREEDING ON PLANARIAN FERTILITY

The influence of inbreeding was studied in the freshwater planarian Du gesia polychroa which, in addition to reproduce by copulation, is able to form self-pairs following experimentally induced regeneration. A c omparative analysis of the degree of fertility of cocoons laid by cros s-pairs and self-pairs, showed that cocoons from the latter contain re markably fewer juveniles which, in addition, are less viable. These re sults were considered to reflect a Darwinian effect of inbreeding depr ession.