Fish use the threat of punishment to keep would-be jumpers in the mating queue firmly in line and the social order stable, a new study led by Australian marine scientists has found.
Their discovery, which has implications for the whole animal kingdom including humans, has been hailed by some of the worlds leading biologists as a must read scientific paper and published in the Proceedings of the Royal Society of London Series B.
Studying small goby fish at Lizard Island on Australias Great Barrier Reef, Dr Marian Wong and colleagues from the ARC Centre of Excellence for Coral Reef Studies at James Cook University and, the Biological Station of Donana, Spain, have shown the threat of expulsion from the group acts as a powerful deterrent to keep subordinate fish from challenging those more dominant than themselves.
In fact the subordinate fish deliberately diet - or starve themselves - in order to remain smaller than their superiors and so present no threat that might lead to their being cast out, and perishing as a result.
Many animals have social queues in which the smaller members wait their turn before they can mate. We wanted to find out how they maintain stability in a situation where youd expect there would be a lot of competition, says Dr Wong.
In the case of the gobies, only the top male and top female mate, and all the other females have to wait their turn in a queue based on their size the fishy equivalent of the barnyard pecking order.
Dr Wong found that each fish has a size difference of about 5 per cent from the one above and the one below it in the queue. If the difference in size decreases below this threshold, a challenge is on as the junior fish tries to jump the mating queue and the superior one responds by trying to drive it out of the group.
Her fascinating discovery is that, in order to avoid constant fights and keep the social order stable, the fish seem to accept the thr
Contact: Dr. Marian Wong
ARC Centre of Excellence in Coral Reef Studies