Featured Research

from universities, journals, and other organizations

Zoologists Challenge Longstanding Theory That 'Eyespots' Mimic The Eyes Of Predators' Enemies

Date:
February 28, 2008
Source:
University of Cambridge
Summary:
Circular markings on creatures such as butterflies are effective against predators because they are conspicuous features, not because they mimic the eyes of the predators' own enemies, according to new research. Many animals possess protective markings to avoid predation, including patterns to reduce the risk of detection (camouflage), to indicate that the animal is toxic or inedible ('warning colors'), or to mimic another animal or object ('mimicry' and 'masquerade'). In addition, many creatures such as butterflies, moths, and fish possess two or more pairs of circular markings, often referred to as 'eyespots'. Many eyespots are effective in startling or intimidating predators, and can help to prevent or stop an attack. For the past 150 years it has been assumed that this is because they mimic the eyes of the predator's own enemies.

Circular markings on creatures such as butterflies are effective against predators because they are conspicuous features, not because they mimic the eyes of the predators' own enemies, according to new research.
Credit: iStockphoto/Charlie Gray

Circular markings on creatures such as butterflies are effective against predators because they are conspicuous features, not because they mimic the eyes of the predators’ own enemies, according to research in the journal, Behavioral Ecology*. Zoologists based at the University of Cambridge challenge the 150-year-old theory about why these markings are effective against predators.

Many animals possess protective markings to avoid predation, including patterns to reduce the risk of detection (camouflage), to indicate that the animal is toxic or inedible (‘warning colours’), or to mimic another animal or object (‘mimicry’ and ‘masquerade’). In addition, many creatures such as butterflies, moths, and fish possess two or more pairs of circular markings, often referred to as ‘eyespots’. Many eyespots are effective in startling or intimidating predators, and can help to prevent or stop an attack. For the past 150 years it has been assumed that this is because they mimic the eyes of the predator’s own enemies.

However, recent work by University of Cambridge zoologists, Martin Stevens, Chloe Hardman, and Claire Stubbins, indicates that this widely-held hypothesis has no experimental support.

Stevens, Hardman, and Stubbins tested the response of wild avian predators to artificial moths, created from waterproof paper. Specific patterns, such as intimidating eyespots of different shapes, sizes and number, and with different levels of eye mimicry, were printed on to the paper using a high quality printer. These ‘moths’ were then pinned to trees of various species at a height of one to three metres in the mixed deciduous Madingley Woods in Cambridgeshire, UK. Attached to each of the artificial moths was an edible mealworm as a temptation for woodland birds such as the blue tits, great tits, blackbirds, and house sparrows.

The zoologists discovered that artificial moths with circular markings survived no better than those with other conspicuous features and that the features of eyespots which most encouraged predators to avoid them are large size, a high number of spots, and conspicuousness in general.

As Dr Stevens explains, ‘the birds were equally likely to avoid artificial moths with markings such as bars and squares as they were to avoid those with two eye-like markings. This leads us to conclude that eyespots work because they are highly conspicuous features, not because they mimic the eyes of the predators’ own enemies. This suggests that circular markings on many real animals need not necessarily, as most accounts claim, mimic the eyes of other animals.’

*Journal reference: Conspicuousness, not eye mimicry, makes ‘‘eyespots’’ effective antipredator signals (Martin Stevens, Chloe J. Hardman, and Claire L. Stubbins) Behavioral Ecology doi:10.1093/beheco/arm162


Story Source:

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


Cite This Page:

University of Cambridge. "Zoologists Challenge Longstanding Theory That 'Eyespots' Mimic The Eyes Of Predators' Enemies." ScienceDaily. ScienceDaily, 28 February 2008. <www.sciencedaily.com/releases/2008/02/080221090250.htm>.
University of Cambridge. (2008, February 28). Zoologists Challenge Longstanding Theory That 'Eyespots' Mimic The Eyes Of Predators' Enemies. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/02/080221090250.htm
University of Cambridge. "Zoologists Challenge Longstanding Theory That 'Eyespots' Mimic The Eyes Of Predators' Enemies." ScienceDaily. www.sciencedaily.com/releases/2008/02/080221090250.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
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
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
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

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