%A Claude Goulet
%A Jacques P. Beaugrand
%T Relation between dominance rank, prior  agonistic intensity and subsequent aggressive levels  in winners and losers of  dyads of male Green swordtail fish (Xiphophorus helleri)
%X Aggressive scores obtained in a mirror test  1h before  an encounter were found to be a good predictor of  victory in male Xiphophorus dyads showing less than 5% size differences. Out of 36 dyad members showing higher  aggressive scores at pre-test, 28  obtained victory in  the subsequent encounter.  It was found that  future winners were more aggressive than future losers to their own image in mirror tests before their encounter. Initial individual aggressive levels in mirror tests were also found to be  a function of the rank the individuals occupied in their home hierarchies.  The higher the rank, the higher was the individual aggressive level as measured by mirror pre-tests, as well as by post-tests. This relationship applied to future winners, as well as to future losers.  The level of aggression reached during agonistic encounter was not a function of the social ranks the opponents occupied in their home hierarchies. Males in dyads composed of two omegas fought as fiercely as males in dyads of two alphas or two betas. No significant relationship was noted between the initial individual aggressive scores at mirror pre-test and  the levels of aggression reached during encounters.  We found in winners  the existence of a significant correlation between the aggressive level they reached during agonistic encounter and a subsequent increase in aggressive levels at mirror tests 1h and 24h after victory.  The more intense the agonistic encounter, the more important  the subsequent increase in aggressive level in winners; an increase which was still detectable 24h after victory.  However, prior alpha winners were apparently not as sensitive as prior betas and prior omegas to the aggressive level reached during the encounter  since their mirror scores obtained after victory did not change when compared to their baseline at pre-test.  After defeat, losers  did not show any significant change in  aggressive scores in mirror tests. Moreover, it was found that encounters in which a 1h resident met an intruder were in general less aggressive than encounters between  two intruders.  Experiential effects are discussed as instances of learning and generalisation.  



%D 2001
%K Agonistic experience; Aggressive behaviour;  Dominance; Subordination; Mirror test; Green swordtail fish; Xiphophorus helleri
%L cogprints1935

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