Featured Research

from universities, journals, and other organizations

Butterfly 'eyespots' add detail to story of evolution

Date:
May 27, 2014
Source:
Oregon State University
Summary:
A new study of the colorful 'eyespots' on the wings of some butterfly species is helping to address fundamental questions about evolution that are conceptually similar to the quandary Aristotle wrestled with about 330 B.C. -- 'which came first, the chicken or the egg?' After a couple thousand years, we're getting closer to the right answer.

The eyespots on this squinting bush brown butterfly are helping researchers answer questions about fundamental evolution.
Credit: William Piel

A new study of the colorful "eyespots" on the wings of some butterfly species is helping to address fundamental questions about evolution that are conceptually similar to the quandary Aristotle wrestled with about 330 B.C. -- "which came first, the chicken or the egg?"

After consideration, Aristotle decided that both the egg and the chicken had always existed. That was not the right answer. The new Oregon State University research is providing a little more detail.

The study, published in Proceedings of the Royal Society B, actually attempts to explain the existence of what scientists call "serial homologues," or patterns in nature that are repetitive, serve a function and are so important they are often retained through millions of years and across vast numbers of species.

Repeated vertebra that form a spinal column, rows of teeth, and groups of eyespots on butterfly wings are all examples of serial homologues. Researchers have tracked the similarities and changes of these serial features through much time and many species, but it's remained a question about how they originally evolved.

Put another way, it's easier to see how one breed of chicken evolved into a different breed of chicken, rather than where chickens -- or their eggs -- came from to begin with.

Butterfly wings are helping to answer that question. These eyespots, common to the butterfly family Nymphalidae, now serve many butterflies in dual roles of both predator avoidance and mate identification. One theory of their origin is that they evolved from simpler, single spots; another theory is that they evolved from a "band" of color which later separated into spots.

"What we basically conclude is that neither of the existing theories about butterfly eyespots is correct," said Jeffrey Oliver, a postdoctoral scholar in the Department of Integrative Biology of the OSU College of Science. "The evidence suggests that a few eyespots evolved as a group at about the same time, but behaved somewhat as individual entities."

Having appeared as a result of some genetic mutation, however, the eyespots then had the capability to move, acquire a function that had evolutionary value, and because of that value were retained by future generations of butterflies. And at all times, they retained the biological capacity for positional awareness -- the eyespots formed in the same place until a new mutation came along.

"At first, it appears the eyespots helped this group of butterflies with one of the most basic aspects of survival value, which is avoiding predators," Oliver said.

On the side of the wing that predators saw when the wings were closed, the eyespots could have served as camouflage from a distance, and up close almost a "bulls-eye" for a predator to see and attack. But this directed the attack toward the tips of less-important wings, and not the more vulnerable head or body of the insect.

But just as important, Oliver said, the study indicates how through continued mutation these eyespots moved to a completely different place -- the other side of the wing. There, they performed a completely different function -- helping the butterfly to attract and be identified by optimal mates.

"If you take this same concept and apply it to other important features like vertebra and a spinal column, it suggests that some small number of bones would form through mutation, and eventually move, join and be perpetuated as they acquired a function with survival value," Oliver said.

"There would be a biological position in which they were supposed to form, and that would be retained," he said. "And over time, the vertebra might expand in number, and acquire other functions that had nothing to do with their original function, but which still had value."

The evolution of life has never been simple, as Aristotle and the other early philosophers found out. But one bone or butterfly eyespot at a time, the pieces continue to come together.


Story Source:

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


Journal Reference:

  1. J. C. Oliver, J. M. Beaulieu, L. F. Gall, W. H. Piel, A. Monteiro. Nymphalid eyespot serial homologues originate as a few individualized modules. Proceedings of the Royal Society B: Biological Sciences, 2014; 281 (1787): 20133262 DOI: 10.1098/rspb.2013.3262

Cite This Page:

Oregon State University. "Butterfly 'eyespots' add detail to story of evolution." ScienceDaily. ScienceDaily, 27 May 2014. <www.sciencedaily.com/releases/2014/05/140527215009.htm>.
Oregon State University. (2014, May 27). Butterfly 'eyespots' add detail to story of evolution. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2014/05/140527215009.htm
Oregon State University. "Butterfly 'eyespots' add detail to story of evolution." ScienceDaily. www.sciencedaily.com/releases/2014/05/140527215009.htm (accessed July 29, 2014).

Share This




More Plants & Animals News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) 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