How fishes decide their social status

Washington, June 29 (ANI): Delving deep into the social hierarchy among male mosquitofish, researchers at the University of Sydney are trying to find out why some fishes seem to slip naturally into their dominant role but others resign themselves to play the part of lowly subordinates.

The researchers studied the interactions between male mosquitofish to see if their behavioural strategy can be traced down to their physical skills.

When the researchers measured the speed of escape in response to an attack, it was found that subordinate fish were significantly faster than the dominant ones.

"This is particularly interesting because we predicted the opposite: that dominant fish were the ones that would prove to be more athletic. Our data indicate either that there may be a training effect because subordinate fish have to escape quickly and often, or that slower fish become more aggressive because they cannot manoeuvre quickly," said Dr. Frank Seebacher, who led the research team.

The team also analysed whether damage to the tail and fins might affect the social position of a given individual, and found that, indeed, aggressive behaviours tended to decline as fin damage sustained in fights accumulates.

This means that if a male has to fight too often to maintain his dominant status, he will probably end up losing it in the end.

The scientists are currently trying to better characterize the physiological differences between the two groups to find out whether they are hereditary or acquired.

They are also planning to address this question by conducting breeding studies designed to distinguish between underlying genetic differences in locomotor performance and plastic changes occurring during the lifetime of the individual as a result of its social status.

Ultimately, they want to determine if relative position within the stable hierarchy is largely influenced by their inherited genes, or if each generation has to work it out all over again.

The results were presented at the Society of Experimental Biology Annual Meeting in Glasgow. (ANI)