Colour-morph dominance and avoidance responses of Anemonia sulcata

Anemonia sulcata is found as one of two colour varieties, a green and a brown form. When pairs or small groups of different colour morphs are placed within tentacle range the green anemones actively avoid contact with the brown forms. Avoidance consists of a “distancing” response which consists of several hours of locomotory behaviour during which the anemone moves at an average speed of around 7–11 cm hr−1. Contacts between individuals of a single colour morph may also lead to a locomotory response as the anemones “space” themselves out. This behaviour takes them just out of tentacle range at speeds around 1–3 cm hr−1. Distancing was not observed between individuals of a single colour morph and brown individuals appear to be dominant over the green variety.