Fighting cichlids: Dynamic of intrasexual aggression in dyadic agonistic encounters

• Published in: Behavioural processes 2018-02, Vol.147, p.61-69
• Main Authors: Scaia, María Florencia, Morandini, Leonel, Noguera, Cristobal Alejandro, Ramallo, Martín Roberto, Somoza, Gustavo Manuel, Pandolfi, Matías
• Format: Article
• Language: English
• Subjects: Aggression; Aggressive behaviour; Aggressiveness; Animal behavior; Cichlasoma dimerus; Contest; Females; Fish; Intra-species interaction; Latency; Males; Motivation; Physical characteristics; Subordination
• ISSN: 0376-6357; 1872-8308
• DOI: 10.1016/j.beproc.2017.12.015

•Encounters followed three phases: pre-contest, contest and post-resolution.•From a total of 17 intrasexual encounters, 16 resulted in a winner/loser status.•Female winners were larger than losers, but this was not the case for males.•In females, higher levels of aggression occurred in contests with similar fish.•Both sexes were equally aggressive and had similar motivation towards aggression. Aggression is an extremely complex behaviour and female aggression is understudied when compared to males. Despite the fact that it has been suggested that conflict among females may be more frequently resolved peacefully, in many species females show high levels of aggression. We used Cichlasoma dimerus to describe dynamics and conflict outcome in intrasexual agonistic encounters. We performed encounters of two sex-matched animals in a neutral arena and we recorded agonistic interactions during one hour. All aggressive and submissive behaviours were described and quantified to perform the ethogram. Encounters followed three phases: pre-contest, contest and post-resolution. Latency, time of resolution and frequency of aggressive displays did not differ between sexes. Relative variations in size between female opponents better explained aggression outcome in each contest, since higher levels of aggression occurred in dyads of more similar fish. However, this was not observed in males, suggesting that probably morphological characteristics could be less relevant in male conflict resolution. Altogether these results suggest that in this ethological context, C. dimerus females are as aggressive as males and that they have similar motivation towards territorial aggression, emphasizing the need of deepening the study of aggression in females and not only in males.