Featured Research

from universities, journals, and other organizations

Army Ants Have Defied Evolution For 100 Million Years

Date:
May 9, 2003
Source:
Cornell University
Summary:
Army ants, nature's ultimate coalition task force, strike their prey en masse in a blind, voracious column and pay no attention to the conventional wisdom of evolutionary biologists.

ITHACA, N.Y. -- Army ants, nature's ultimate coalition task force, strike their prey en masse in a blind, voracious column and pay no attention to the conventional wisdom of evolutionary biologists.

Related Articles


The common scientific belief has been that army ants originated separately on several continents over millions of years. Now it is found there was no evolution. Using fossil data and the tools of a genetics detective, a Cornell University entomologist has discovered that these ants come from the same point of origin, because since the reign of the dinosaurs, about 100 million years ago, army ants in essence have not changed a bit.

"Biologists have wondered why army ants, whose queens can't fly or get caught up by the wind, are yet so similar around the world. Army ants have evolved only once and that was in the mid-Cretaceous period," says Sean Brady, a Cornell postdoctoral researcher in entomology, whose study was conducted while he was doctoral candidate at the University of California-Davis.

Brady's paper, "Evolution of army ant syndrome: the unique origin and long-term evolutionary stasis of a novel complex of behavioral and reproductive adaptation," will be published on the Web by the Proceedings of the National Academy of Science (PNAS) Online Early Edition between May 5 and May 9 before being printed in PNAS.

Army ants are quite unlike the ants commonly found at family picnics. They have what scientists call the "army ant syndrome," comprising three characteristics: the ants are nomadic, they forage for prey without advance scouting, and their wingless queens can produce up to 4 million eggs in a month. While this syndrome is found in every army ant species around the world, scientific papers have postulated that army ants evolved these characteristics multiple times after the breakup of the supercontinent Gondwana about 100 million years ago.

In total, Brady studied the DNA of 30 army ant species and 20 possible ancestors within the army ant community, divided between the New World species in Ecitoninae and the Old World groups Aenictinae and Dorylinae. He specifically sought information from four different genes to uncover clues to their relationships. "Essentially I built a genetic family tree. Then I took that family tree and looked at its genetic tree rings to postulate what happened in the past," he said.

Brady combined the genetic data with the army ant fossil information and the ants' morphological (form and structure) information to establish ages for the different ant species. Combining this data, Brady found that all the species share some of the same genetic mutations. "If they share those mutations, we can infer they evolved from the same source," Brady said.

Instead of proving the common assumption that the Old World and the New World army ants developed their lineage independently on separate continents, the entomologist showed the ants evolved only once -- on Gondwana.

Brady examined the army ants' behavior on his trips to the Amazon jungle, Brazil's savanna region and the country's coastal rain forest near São Paulo. Periodically millions of army ants would march together through his camp, he says, like a flowing river of red. While the ants move silently, their presence is announced. "The other insects are scared, and they make noises as they flee the invading army," Brady says. "Ant birds follow the ants from the sky and feast on the remnants left behind by the ants. You will hear the high-pitched chirping of the other insects, and you'll hear them and other small animals scurrying in fear. They know what is next."


Story Source:

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


Cite This Page:

Cornell University. "Army Ants Have Defied Evolution For 100 Million Years." ScienceDaily. ScienceDaily, 9 May 2003. <www.sciencedaily.com/releases/2003/05/030507081357.htm>.
Cornell University. (2003, May 9). Army Ants Have Defied Evolution For 100 Million Years. ScienceDaily. Retrieved April 19, 2015 from www.sciencedaily.com/releases/2003/05/030507081357.htm
Cornell University. "Army Ants Have Defied Evolution For 100 Million Years." ScienceDaily. www.sciencedaily.com/releases/2003/05/030507081357.htm (accessed April 19, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, April 19, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Reuters - US Online Video (Apr. 17, 2015) — A truck carrying honey bees overturns near Lynnwood, Washington, spreading boxes of live bees across the highway. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Our Love Of Puppy Dog Eyes Explained By Science

Our Love Of Puppy Dog Eyes Explained By Science

Newsy (Apr. 17, 2015) — Researchers found a spike in oxytocin occurs in both humans and dogs when they gaze into each other&apos;s eyes. Video provided by Newsy
Powered by NewsLook.com
Dog Flu Spreading in Midwestern States

Dog Flu Spreading in Midwestern States

AP (Apr. 17, 2015) — Dog flu is spreading in several Midwestern states. Dog daycare centers and veterinary offices are taking precautions. (April 17) Video provided by AP
Powered by NewsLook.com
Raw: Rare Whale Spotted in Gulf of Mexico

Raw: Rare Whale Spotted in Gulf of Mexico

AP (Apr. 17, 2015) — Researchers from the E/V Nautilus had quite a surprise Tuesday, when a curious sperm whale swam around their remotely operated vehicle in the Gulf of Mexico. Cameras captured the encounter. (April 17) 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:

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