Featured Research

from universities, journals, and other organizations

Looking Different 'Helps Animals To Survive'

Date:
August 9, 2009
Source:
University of York
Summary:
In the animal kingdom, everything is not as it seems. Individuals of the same species can look very different from each other -- what biologists term "polymorphism." Sometimes the number of distinct visible forms -- "exuberant polymorphisms" -- in a single animal population can reach double figures. But why? Scientists have now developed computer models that may help to explain how this level of variation arises and persists.

A prime example of an exuberant polymorphism is the Hawaiian Happy-face Spider, which has been studied by Dr Geoff Oxford and colleagues.
Credit: Image courtesy of University of York

In the animal kingdom, everything is not as it seems. Individuals of the same species can look very different from each other – what biologists term ‘polymorphism.’

Sometimes the number of distinct visible forms – ‘exuberant polymorphisms’– in a single animal population can reach double figures. But why?

Scientists at the University of York have developed computer models that may help to explain how this level of variation arises and persists.

A prime example of an exuberant polymorphism is the Hawaiian Happy-face Spider, which has been studied by Dr Geoff Oxford and colleagues in the University’s Department of Biology. The variations range from a common plain yellow form to rare types sporting red, black or white marks, all of which are inherited.

Dr Oxford said: “It has always been a real mystery why every population of this spider across different Hawaiian islands contains such high levels of variation. This was the starting point for our models.”

Previously scientists believed that ‘apostatic predation’ was the most likely explanation for polymorphisms. This process involves predators developing mental search images of the appearance of the most common prey, so they are more likely to overlook prey of a different appearance. A strange consequence is that looking different from others stops an individual from standing out. This results in evolutionary selection on the prey to look different from the most common form.

However, the York researchers found that apostatic selection could not explain the sheer number of distinct forms involved in the exuberant polymorphisms of some species, but that ‘dietary wariness’ could. Dietary wariness is a hesitancy of predators to consume a novel food item and a consequent reluctance to incorporate it into their regular diet. The new research suggests that a modest level of predator dietary wariness can, on its own, lead to the maintenance of large numbers distinct prey forms within a single species.

Dr Daniel Franks, of the University’s York Centre for Complex Systems Analysis, said: “A mutant prey individual that looks different from its fellows has a survival advantage because it will be unfamiliar to predators that will be reluctant to change their diet to accommodate it. Some prey species have evolved polymorphisms to deter predators by presenting them with a large number of visually novel foods.”


Story Source:

The above story is based on materials provided by University of York. Note: Materials may be edited for content and length.


Journal Reference:

  1. Daniel W. Franks and Geoff S. Oxford. The evolution of exuberant visible polymorphisms. Evolution, Published Online 10 Jun 2009 DOI: 10.1111/j.1558-5646.2009.00748.x

Cite This Page:

University of York. "Looking Different 'Helps Animals To Survive'." ScienceDaily. ScienceDaily, 9 August 2009. <www.sciencedaily.com/releases/2009/07/090723113514.htm>.
University of York. (2009, August 9). Looking Different 'Helps Animals To Survive'. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2009/07/090723113514.htm
University of York. "Looking Different 'Helps Animals To Survive'." ScienceDaily. www.sciencedaily.com/releases/2009/07/090723113514.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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