Feeding segregation of two sympatric eubranchiid nudibranchs (Aeolidacea)

Two closely related species of aeolid nudibranchs, Eubranchus misakiensis and E. horii, were found abundantly on the same leaves of seaweeds, Ecklonia kurome. Three thecata hydroid species also grew in large numbers on the surface of the weeds. E. misakiensis occurred always only on colonies of Obelia geniculata, with E. horii always only on colonies of Plumularia filicaulis japonica. Neither aeolid was found on Orthopyxis platicarpa. These field observations and results of choice experiments demonstrate considerable feeding segregation in the two aeolids.