INTRASPECIFIC AGGRESSION IN THE COLOR MORPHS OF THE ANEMONE ACTINIA-EQUINA - CONVENTION GOVERNING DOMINANCE RANKING

The aggressive behaviour of red-brown and green Actinia individuals during intra- and inter-colour morph encounters staged in the laboratory is described. By considering the colours and relative sizes of the opponents it is shown that the outcomes of contests are predictable to the observer. Red-brown anemones were highly aggressive. Larger individuals attacked before smaller opponents, and subsequently won encounters. A variable threshold for aggression appears to underlie this difference; an attempt to correlate threshold with absolute size was only partially successful. Using the results of many encounters, it has proved possible to establish a branching and overlapping dominance hierarchy amongst red-brown anemones. Green individuals were less aggressive and predominantly lost contests with red-brown anemones. © 1979.