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 July 30, 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 July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) 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