Hawk-like aggression in the Hawaiian red lobster, Enoplometopus occidentalis

Based upon current game theory and previously established biological criter ia we attempted to empirically demonstrate the existence of a species that displays hawk-like levels of aggression. To do this we studied aggression i n the Hawaiian red lobster, Enoplometopus occidentalis. Twelve mated pairs of lobsters were tested, using four pairs per trial. Results suggest that t hese lobsters display hawk-like aggression. While intersexual and intrasexu al encounters were equally likely to occur, aggression was restricted to in trasexual encounters with males and females displaying the same high levels of aggression. Assessment of encounters based upon size, home tank, and da mage inflicted indicated that damage inflicted was the only reliable indica tor of winning, and 83.3% of all lobsters suffered damage by the end of the experiment. Even after damage was inflicted and individuals retreated, 'wi nners' continued to pursue, indicating a lack of submissive behaviours. The behavioural interactions between unmated males and females indicated that this species does not display mate choice. Finally, the results indicate th at cheliped-to-cheliped contact is important, if not obligate, for sexual r ecognition.