![The relationship between large fish and their small, cleaner-service counterparts is a fascinating one in itself. Cleaner fish such as the bluestreak cleaner wrasse (Labroides dimidiatus) operate from home territories called cleaning stations, made up of a single male with a harem of around 16 females, to which fish will “drop in” daily to use their services - namely the removal of potentially harmful parasites, such as lice. In the true style of business, the fish at each station charm their customers into staying with their specific service by careful stroking and caressing.But the bluestreak cleaner wrasse in particular is exceptionally interesting. While the fish don’t mind eating parasites, in actual fact their preference is for mucus - which in order to gain, requires taking a bite out of the customer. Unfortunately, the larger fish are unlikely to take too kindly to having a chunk taken out of them, and will probably respond by attacking the cleaner fish, swimming away, and not returning again to that cleaning station. As a result, the male bluestreak cleaner wrasse punish their females should they bite the customers, chasing them and trying to bite them - and the punishment is more severe the worse the crime. This is quite impressive; while punishment behaviour has been seen in other animals than humans, it is rare that the severity varies according to the offense - the fish must somehow make a judgement, and punish accordingly.More interesting still is that the punishment is not only in place in order to maintain custom. The male has to prevent his females growing bigger than him - because if they do, they will change sex into a male within just two days and beat him off his territory. As it happens, all bluestreak cleaner wrasse are born female, the largest female in the area then developing into the dominating male. The male therefore doesn’t want the female getting a good meal, while he loses out as his dissatisfied customer swims away. Amazing stuff!Ref: Marshall (2011) Zoologger: Patriarchal fish punish powerful females. New Scientist [link]](http://25.media.tumblr.com/tumblr_lmw1z4rkqe1qkrbaho1_400.jpg)
The relationship between large fish and their small, cleaner-service counterparts is a fascinating one in itself. Cleaner fish such as the bluestreak cleaner wrasse (Labroides dimidiatus) operate from home territories called cleaning stations, made up of a single male with a harem of around 16 females, to which fish will “drop in” daily to use their services - namely the removal of potentially harmful parasites, such as lice. In the true style of business, the fish at each station charm their customers into staying with their specific service by careful stroking and caressing.
But the bluestreak cleaner wrasse in particular is exceptionally interesting. While the fish don’t mind eating parasites, in actual fact their preference is for mucus - which in order to gain, requires taking a bite out of the customer. Unfortunately, the larger fish are unlikely to take too kindly to having a chunk taken out of them, and will probably respond by attacking the cleaner fish, swimming away, and not returning again to that cleaning station. As a result, the male bluestreak cleaner wrasse punish their females should they bite the customers, chasing them and trying to bite them - and the punishment is more severe the worse the crime. This is quite impressive; while punishment behaviour has been seen in other animals than humans, it is rare that the severity varies according to the offense - the fish must somehow make a judgement, and punish accordingly.
More interesting still is that the punishment is not only in place in order to maintain custom. The male has to prevent his females growing bigger than him - because if they do, they will change sex into a male within just two days and beat him off his territory. As it happens, all bluestreak cleaner wrasse are born female, the largest female in the area then developing into the dominating male. The male therefore doesn’t want the female getting a good meal, while he loses out as his dissatisfied customer swims away. Amazing stuff!
Ref: Marshall (2011) Zoologger: Patriarchal fish punish powerful females. New Scientist [link]
Source: Flickr / danielguip
