Featured Research

from universities, journals, and other organizations

Tiny fish make 'eyes' at their killer

Date:
August 19, 2013
Source:
ARC Centre of Excellence in Coral Reef Studies
Summary:
Small prey fish can grow a bigger 'eye' on their rear fins as a way of distracting predators and dramatically boosting their chances of survival, new research has found. Researchers have made a world-first discovery that, when constantly threatened with being eaten, small damsel fish not only grow a larger false 'eye spot' near their tail -- but also reduce the size of their real eyes.

Small prey fish can grow a bigger ‘eye’ on their rear fins as a way of distracting predators and dramatically boosting their chances of survival, new scientific research has found.
Credit: Image courtesy of ARC Centre of Excellence in Coral Reef Studies

Small prey fish can grow a bigger 'eye' on their rear fins as a way of distracting predators and dramatically boosting their chances of survival, new scientific research has found.

Researchers from Australia's ARC Centre of Excellence for Coral Reef Studies (CoECRS) have made a world-first discovery that, when constantly threatened with being eaten, small damsel fish not only grow a larger false 'eye spot' near their tail -- but also reduce the size of their real eyes.

The result is a fish that looks like it is heading in the opposite direction -- potentially confusing predatory fish with plans to gobble them up, says Oona Lφnnstedt, a graduate student at CoECRS and James Cook University.

For decades scientists have debated whether false eyespots, or dark circular marks on less vulnerable regions of the bodies of prey animals, played an important role in protecting them from predators -- or were simply a fortuitous evolutionary accident.

The CoECRS team has found the first clear evidence that fish can change the size of both the misleading spot and their real eye to maximise their chances of survival when under threat.

"It's an amazing feat of cunning for a tiny fish," Ms Lonnstedt says. "Young damsel fish are pale yellow in colour and have this distinctive black circular 'eye' marking towards their tail, which fades as they mature. We figured it must serve an important purpose when they are young."

"We found that when young damsel fish were placed in a specially built tank where they could see and smell predatory fish without being attacked, they automatically began to grow a bigger eye spot, and their real eye became relatively smaller, compared with damsels exposed only to herbivorous fish, or isolated ones.

"We believe this is the first study to document predator-induced changes in the size of eyes and eye-spots in prey animals."

When the researchers investigated what happens in nature on a coral reef with lots of predators, they found that juvenile damsel fish with enlarged eye spots had an amazing five times the survival rate of fish with a normal-sized spot.

"This was dramatic proof that eyespots work -- and give young fish a hugely increased chance of not being eaten.

"We think the eyespots not only cause the predator to attack the wrong end of the fish, enabling it to escape by accelerating in the opposite direction, but also reduce the risk of fatal injury to the head," she explains.

The team also noted that when placed in proximity to a predator the young damsel fish also adopted other protective behaviours and features, including reducing activity levels, taking refuge more often and developing a chunkier body shape less easy for a predator to swallow.

"It all goes to show that even a very young, tiny fish a few millimetres long have evolved quite a range of clever strategies for survival which they can deploy when a threatening situation demands," Ms Lonnstedt says.


Story Source:

The above story is based on materials provided by ARC Centre of Excellence in Coral Reef Studies. Note: Materials may be edited for content and length.


Journal Reference:

  1. Oona M. Lφnnstedt, Mark I. McCormick, Douglas P. Chivers. Predator-induced changes in the growth of eyes and false eyespots. Scientific Reports, 2013; 3 DOI: 10.1038/srep02259

Cite This Page:

ARC Centre of Excellence in Coral Reef Studies. "Tiny fish make 'eyes' at their killer." ScienceDaily. ScienceDaily, 19 August 2013. <www.sciencedaily.com/releases/2013/08/130819102728.htm>.
ARC Centre of Excellence in Coral Reef Studies. (2013, August 19). Tiny fish make 'eyes' at their killer. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2013/08/130819102728.htm
ARC Centre of Excellence in Coral Reef Studies. "Tiny fish make 'eyes' at their killer." ScienceDaily. www.sciencedaily.com/releases/2013/08/130819102728.htm (accessed August 29, 2014).

Share This




More Plants & Animals News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Raw: Australian Sheep Gets Long Overdue Haircut

Raw: Australian Sheep Gets Long Overdue Haircut

AP (Aug. 28, 2014) — Hoping to break the record for world's wooliest, Shaun the sheep came up 10 pounds shy with his fleece weighing over 50 pounds after being shorn for the first time in years. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) — Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Fake Dogs Scare Real Geese from Wis. Park

Fake Dogs Scare Real Geese from Wis. Park

AP (Aug. 28, 2014) — Parks officials in Stevens Point, Wisconsin had a fowl problem. Canadian Geese were making a mess of a park, so officials enlisted cardboard versions of man's best friend. (Aug. 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins