Genetic and ecological differentiation between sympatric colour morphs of the common intertidal sea anemone Actinia equine

The abundant intertidal sea anemone Actinia equina occurs in a variety of colour morphs of which 3 (green, red, brown) are investigated in the present work. Green anemones are known to be morphologically and behaviourally different from the other colour morphs and may be ecologically distinct; it is also known that green morphs are differentially selected by certain nudibranch predators. Differences between morphs are investigated in detail using large numbers of anemones and employing enzyme electrophoresis as criterion for genetic differentiation. The green morph has clearly different ecological preferences both with respect to mean tidal position on the shore and choice of microhabitat; it also differs significantly at 4 of the 17 enzyme loci examined. According to biochemical evidence there is little or no gene flow between sympatnc populations of green and other colour morphs It is suggested that the green Actjnia should best be regarded as a separate species, and the name Actinla prasjna is proposed.