Featured Research

from universities, journals, and other organizations

How Social Insects Recognize Dead Nestmates

Date:
May 6, 2009
Source:
University of California - Riverside
Summary:
When an ant dies in an ant nest or near one, its body is quickly picked up by living ants and removed from the colony. The predominant understanding among entomologists was that dead ants release chemicals created by decomposition that signal their death to the colony's living ants. But entomologists working on Argentine ants provide evidence for a different mechanism for how necrophoresis -- the removal of dead nestmates from colonies -- works.

This is an Argentine ant worker carrying a dead nestmate (necrophoresis). The rapid dissipation of compounds associated with live ants allows the latent necrophoric behavior to be triggered.
Credit: Dong-Hwan Choe, UC Riverside

When an ant dies in an ant nest or near one, its body is quickly picked up by living ants and removed from the colony, thus limiting the risk of colony infection by pathogens from the corpse.

The predominant understanding among entomologists – scientists who study insects – was that dead ants release chemicals created by decomposition (such as fatty acids) that signal their death to the colony's living ants.

But now UC Riverside entomologists working on Argentine ants provide evidence for a different mechanism for how necrophoresis – the removal of dead nestmates from colonies – works.

In a research paper recently published online in the early edition of the Proceedings of the National Academy of Sciences, the researchers report that all ants, both living and dead, have the "death chemicals" continually, but live ants have them along with other chemicals associated with life – the "life chemicals." When an ant dies, its life chemicals dissipate or are degraded, and only the death chemicals remain.

"It's because the dead ant no longer smells like a living ant that it gets carried to the graveyard, not because its body releases new, unique chemicals after death," said Dong-Hwan Choe, the lead author of the research paper and a graduate student working towards his doctoral degree with Michael Rust, a professor of entomology at UCR.

Choe explained that the research paper's results resolve a conundrum of long-standing in animal behavior and correct a misinterpretation of previous results that has become both popular and widespread in literature.

"There is no mistaking that it is the dissipation of chemical signals associated with life rather than the increase of a decomposition product 'death cue' that triggers necrophoric behavior by Argentine ants," he said.

Along with Rust and UCR's Jocelyn Millar, a professor of entomology, Choe used analytical chemistry techniques to identify the "signals of life" in the Argentine ant: the chemicals dolichodial and iridomyrmecin.

"These chemicals, or compounds similar to them, are found in numerous ant species that display necrophoresis," Choe said. "Therefore, these ant species also are likely to have necrophoric behavior triggered by the decrease or absence of chemical signs of life, rather than by cues associated with death. We plan to research this next."

He added that dolichodal, iridomyrmecin, or similar compounds are found also in other insects, such as thrips, stick insects, aphids and rove beetles.

"Understanding the exact mechanism of ant necrophoresis will help researchers develop a more environmentally friendly pest management strategy by which we can achieve results with smaller amounts of insecticide," Choe said. "A recent study on Argentine ants that we did in the lab indicated that nestmates can efficiently distribute slow-acting and non-repellent insecticides among themselves via necrophoresis. When an ant exposed to an insecticide dies in the nest, other ants carry its body around, with the insecticide transferring easily from the corpse to healthy ants."

Choe's coauthors on the research paper are Millar and Rust. The Carl Strom/Western Exterminator Scholarship, a Pi Chi Omega Scholarship and a Bayer Young Scientist of the Year 2008 Scholarship to Choe funded the three-year study.

Choe, who expects to graduate this summer, received his bachelor of science degree in agriculture from Korea University, Seoul (2002), and his master's degree in entomology from UCR (2005).


Story Source:

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


Journal Reference:

  1. Dong-Hwan Choe, Jocelyn G. Millar, and Michael K. Rust. Chemical signals associated with life inhibit necrophoresis in Argentine ants. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0901270106

Cite This Page:

University of California - Riverside. "How Social Insects Recognize Dead Nestmates." ScienceDaily. ScienceDaily, 6 May 2009. <www.sciencedaily.com/releases/2009/05/090505124750.htm>.
University of California - Riverside. (2009, May 6). How Social Insects Recognize Dead Nestmates. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2009/05/090505124750.htm
University of California - Riverside. "How Social Insects Recognize Dead Nestmates." ScienceDaily. www.sciencedaily.com/releases/2009/05/090505124750.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 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