Strain specificity in a tropical marine sponge

Grafting experiments have provided direct evidence for the occurrence of strain specificity in the marine demosponge Verongia longissima (Carter). All autografts accepted, all xenografts rejected, and there was both acceptance and rejection of allografts. Among allografts, groups of individuals could easily be identified which showed consistent acceptances and rejections of other individuals. The groups were designated as strains. Histological preparations of graft rejections showed the development of a cuticle between the surfaces of the two sponges in contact. The role of specificity in patterns of interactions between sponges in situ has been discussed from an ecological perspective.