Cleaner fish respond to the shadow of the future (w/ Video)

Jun 07, 2010
Cleaner fish respond to the shadow of the future
The image shows Bicolor cleaner fish cleaning inside the gills of Monocle Bream. Copyright Joseph Fenton.

(PhysOrg.com) -- Tropical fish alter their behaviour with an eye to the future, researchers at Cambridge have found. This is the first time such behaviour has been seen in any animals except humans.

Economists use the term "shadow of the future" to describe how humans change the way they behave towards another person depending on the likelihood that the two will meet again in the future. If a future meeting is likely, people tend to behave more cooperatively, while if they are unlikely to meet again they are more likely to cheat each other.

Jenny Oates and colleagues from the University of Cambridge and University of Neuchatel in Switzerland studied tropical cleaner (Labroides bicolor) in their natural environment among the of the South Pacific and found that these fish - like humans - respond to the "shadow of the future".

As their name suggests, cleaner fish feed by removing parasites from the skin, mouths and gills of many other fish (known as client species), including and puffer fish. However, they also sometimes feed by taking a sneaky bite of mucous from the clients' skin.

While removing parasites is cooperative behaviour, benefiting both species, eating mucous is potentially harmful to the client fish because the mucous is part of its immune system.

Oates, a PhD student, found that the cleaner fish behave differently in different areas of their home range. They behave more cooperatively - feeding off clients' parasites - in the parts of their home range where they spend most time and are therefore more likely to meet the same client fish again.

By contrast, they cheat - eating clients' mucous more often - in the parts of their home range that they visit less often, and where they are less likely to re-encounter the client fish they cheated.

According to Oates: "We can spot when a cleaner fish eats parasites from a client and when it takes a sneaky bite of their mucous because eating mucous makes the client fish jump.

"The results suggest that, like humans, cleaner fish are able to take account of the future rather than just the immediate consequences of their actions."

Explore further: Scientists discover tropical tree microbiome in Panama

More information: Current Biology - www.cell.com/current-biology/home

add to favorites email to friend print save as pdf

Related Stories

Over-fishing: Fewer eggs, smaller fish

Jan 19, 2006

A University of California-Riverside study suggests harvesting the largest individuals from a fish population introduces harmful genetic changes.

Recommended for you

Scientists discover tropical tree microbiome in Panama

12 hours ago

Human skin and gut microbes influence processes from digestion to disease resistance. Despite the fact that tropical forests are the most biodiverse terrestrial ecosystems on the planet, more is known about ...

How are hybridized species affecting wildlife?

17 hours ago

Researchers who transplanted combinations of wild, domesticated, and domesticated-wild hybridized populations of a fish species to new environments found that within 5 to 11 generations, selection could remove ...

Japan's whale hunt under scrutiny at IWC meeting

18 hours ago

Japan's intention to resume whale hunts in the Antarctic—despite a ruling by the top U.N. court—topped the agenda as an international whaling conference opened Monday in Slovenia's Adriatic Sea resort ...

User comments : 0