BEIJING: The dottyback takes on the appearance of other fish so that it can sneak up undetected and eat their young, scientists have discovered.
While mimicry is common in nature and practised by animals ranging from cuckoos to butterflies, this master of disguise takes it to a new level.
The coral reef fish is able to change colour in different ways to match whatever species it is hunting.Different types of damselfish are one of its favourite targets.
Dr William Feeney, from Cambridge University’s Department of Zoology, who co-led the study, said: “By changing colour to imitate local damselfish communities, dottybacks are able to overcome the predator avoidance behaviour in the juvenile fish they hunt.
” The dottyback behaviour is comparable to the ‘wolf in sheep’s clothing’ scenario from Aesop’s Fables, where distinguishing the predator from the harmless ‘flock’ becomes increasingly difficult when they look alike – allowing the dottyback to creep up on unsuspecting juvenile damselfish.”
Dottybacks are generally solitary and highly territorial predators around eight centimetres in length.
While they can vary their colouration from pink to grey, the scientists focused on two colour “morphs” – yellow and brown – seen on reefs surrounding Lizard Island, off the north-east coast of Australia.
The area has damselfish that are both yellow and brown.
To test the dottyback’s colour changing ability, the scientists built their own artificial reef outcrops and populated them with either of the damselfish varieties.
When released among damselfish of the opposite colour, the dottybacks would change from yellow to brown or vice versa over a period of about two weeks.
Anatomical studies revealed changes at the cellular level in the dottyback’s skin. The ratio of yellow to black pigment cells shifted to achieve the colour switch.
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