A TEST OF THE SEQUENTIAL ASSESSMENT GAME - FIGHTING IN THE CICHLID FISH NANNACARA-ANOMALA

Many species have a repertoire of behaviour patterns that are used in contests over resources. It is likely that the function of these behaviour patterns is the assessment of asymmetries between contestants in physical variables (e.g. size or strength). Theoretical models of fighting behaviour such as the war of attrition and the hawk-dove game do not incorporate any behavioural mechanisms allowing assessment, and, therefore, yield no predictions about the use of behaviour patterns. In a sequential assessment game, on the other hand, the assessment of asymmetries is a major activity during a fight. Recently, a version of the sequential assessment game with several behavioural options has been developed, and here predictions from this model are tested using data from 102 staged fights between males of the cichlid fish Nannacara anomala. The model predicts that the sequence of behaviour patterns in a fight should be maximally efficient in assessing relative fighting ability. Specific predictions are that (1) the sequence should be organized into phases consisting of one or several behaviour patterns with constant rates of behaviour within a phase, (2) the division into phases should be independent of relative fighting ability, and (3) contests with great asymmetry in relative fighting ability should end in an early phase, whereas matched individuals may proceed through a series of escalations reaching a final phase of more dangerous fighting. The results show that the fighting behaviour of N. anomala is rather well predicted by the model. © 1990 The Association for the Study of Animal Behaviour.