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Updated: Jan 2, 2026

The Resident-intruder Paradigm: A Standardized Test for Aggression, Violence and Social Stress
Published on: July 4, 2013
Social context affects aggression and brain vasotocin and isotocin level in the round goby
Ewa Sokołowska1, Magdalena Gozdowska2, Ewa Kulczykowska2
1Department of Genetics and Marine Biotechnology, Institute of Oceanology, Polish Academy of Sciences, ul. Powstańców Warszawy 55, 81-712, Sopot, Poland. ewasokol@iopan.gda.pl.
Abstract:
On the wild spawning grounds, the round gobies Neogobius melanostomus are subjected to different social cues, such as sex-separation and high fish density. We designed an experiment to stimulate natural social stress when fish are separated from opposite sex individuals and exposed to close proximity of same-sex conspecifics. We examined the effects of different sex compositions on aggressiveness and brain concentrations of arginine vasotocin (AVT) and isotocin (IT), as AVT and IT are known to be involved in aggressive interactions during reproduction. The round gobies were kept in three experimental groups: same-sex groups broken down into male-only and female-only groups and mixed-sex groups. In this study, males and females from same-sex groups showed overt aggression and competition. Separation stress stimulated aggressive responses in both sexes, but the link between brain AVT and IT concentration and aggressive behavior was evident only in male-only group. In the male-only group, AVT and IT levels were the highest. This study shows that sex composition of the social environment can affect aggressive behavior as well as AVT and IT concentration in the whole brain of the round goby.
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