The Herpetological Journal

pp.15-19

Authors: Ricardo Reques And Miguel Tejedo

Abstract: The most striking social behaviour in urodele tadpoles is overt aggression against conspecific or heterospecific larvae that may result in harmful injuries, predation or cannibalism. In this study we analysed under laboratory conditions aggressive behaviour in fire salamander, Salamandra salamandra, larvae. The aims of our study were: ( 1) to analyse the function of visual and movement displays in the context of agonistic behaviour; (2) to examine whether relative body size between individuals influences the frequency of aggressive interactions; and, (3) to determine the effect of larval density on the frequency of these aggressive interactions. The analysis of patterns that preceded a direct act of aggression (i.e. lunge or bite) revealed that the initiator of the contest exhibited more attacking patterns and that the receiver displayed more escape acts. Relative body size significantly affected the frequency of aggressive acts. The proportion of aggressive acts performed by the larger larva was positively related to relative larval body size. Density significantly affected the number of aggressive interactions observed. Significantly more aggressive acts were received or displayed by the focal larva at high density. Body size seems to be an important cue which is correlated with the outcome of aggressive interactions in Salamandra salamandra larvae. By visually assessing size asymmetry, individuals are able to use this difference to assess fighting ability, and can adjust their behaviour accordingly to avoid escalation of the aggressive encounter