The Bluestreak Cleaner Wrasse (Labroides dimidiatus) can often be seen in pairs, cleaning fish on the reef, doing what most would consider a self-less service–eating parasites. Unknown to most aquarists is that the Wrasse’s favorite meal is not parasites, but the layer of mucus covering their fish clients. Being in the ‘service industry’, nibbling at [...]
The Bluestreak Cleaner Wrasse (Labroides dimidiatus) can often be seen in pairs, cleaning fish on the reef, doing what most would consider a self-less service–eating parasites. Unknown to most aquarists is that the Wrasse’s favorite meal is not parasites, but the layer of mucus covering their fish clients. Being in the ‘service industry’, nibbling at this mucus often leads to disgruntled fish that will swim away. Scientists are considering this cheating on the customer as it breaks the symbiosis and harms the client. It’s simply bad for long term business.
In a recent study it was found that Male L. dimidiatus will actually ‘punish’ its female counterpart for this cheating behavior. But don’t think ‘altruism’, think business. It is proposed that this third party punishment is simply driven by self interest or in this case a loss of potential food. Dr. Raihani took this third party punishment to the lab where pairs of L. dimidiatus were fed ‘prawn goop’ or fish flakes smeared on a plastic plate.
The fish much preferred the prawns, but the second the female ate any of the prawn food, the plate was removed. It was shown that when the males subsequently acted aggressively towards the female, they were less likely to ‘cheat’ (by eating the prawns) in the future underlining the notion that the punishment would allow a better relationship to take place with the ‘fish client’ and allow more food for all. The males were not actually harmed by females eating the prawns, but by punishing them it gave the male an advantage for future food consumption.
The establishment of self-serving third-party punishment in response to personal losses may be a key step toward third-party punishment without current involvement, as in humans. …Male cleaner fish, Labroides dimidiatus, punish their female partner if she cheats while inspecting model clients. Punishment promotes female cooperation and thereby yields direct foraging benefits to the male. Thus, third-party punishment can evolve via self-serving tendencies in a nonhuman species, and this finding may shed light on theevolutionary dynamics of more complex behavior in other animal species, including humans.
See more information in the study:
Punishers Benefit from Third-Party Punishment in Fish, Nichola J. Raihani, Alexandra S. Grutter and Redouan Bshary, Science, 8 Jan. 2010.
photo cc [flickr : dougdeep]
