Quantitative study on the reproduction of two strains of agamic planarians Dugesia gonocephala and Dugesia tigrina

Abstract In two asexual planarian strains (Dugesia gonocephala and Dugesia tigrina), reproduction by transverse fission and regeneration is observed under normal conditions and upon decapitation and reserpine treatment. The pattern of asexual reproduction processes in planarians, as it results from our quantitative observations compared with the literature data, indicates that autotomy and regeneration processes have an extremely wide range of possible expressions. In such a heterogeneous situation it is still possible to suppose the existence of a negative cephalic control of fissiparity, similar to the ones involved in general tissue organization and in the regeneration of planarians.