Research predicts growth, survival of 'superorganism' ant colonies

Dec 19, 2012

(Phys.org)—Smaller ant colonies tend to live faster, die younger and burn up more energy than their larger counterparts, as do the individual ants that make up those colonies, according to new research that views the colonies as "superorganisms" in which social insects function much like the cells of a body.

The research, published in the Dec. 23 issue of the journal , describes a new that can predict the survival, growth and of ant colonies. Dr. Chen Hou, an assistant professor of at Missouri University of Science and Technology, is one of the authors of the study and developed the mathematical models used to predict colony growth and survival.

Hou also collected some of the data used for the Biology Letters study, titled "Towards a general life-history model of the superorganism: predicting the survival, growth and reproduction of ant societies."

In the article, Hou and his colleagues compared the rates of metabolism, growth, reproduction and longevity of individual ants with those same traits for entire colonies. He based his models on Kleiber's Law, the observation that the for organisms - the rate at which they process and use over time - tends to increase at a rate that is to the 3/4 power of that organism's body mass. Named after Max Kleiber's biological work in the early 1930s, Kleiber's Law is also known as "quarter-power scaling."

As Hou explains it, a horse may be 10,000 times heavier than a mouse, but it doesn't consume 10,000 times more energy. Applying quarter-power scaling, researchers can determine that a horse, which is 10,000 times larger than the mouse, only consumes 1,000 times more energy (because 10,000 to the 3/4 power equals 1,000).

The same phenomena holds true at the , Hou says. Two similar organ cells from two different organisms -a mouse and a horse, for instance - do not use proportionately equal amounts of energy. "The one from the horse needs and uses much less energy than the one from the mouse," even though both cells have the same purpose and function, Hou says.

In ant colonies, that same phenomenon applies, Hou and his colleagues point out in the Biology Letters study. The ants behave more like the cells of animal and their colonies more like the animal itself - which is why the researchers classify colonies as "superorganisms." The individual ants of larger colonies consume and use less energy than their counterparts in smaller colonies, just as the cells of a horse consume and use less energy than the cells of a mouse.

Combining data from actual with predictions based on mathematical models, the researchers found that and metabolic rates increased at a consistent, nearly three-quarter-power scaling rate for worker ants and queen ants alike, as well as for their colonies.

Based on these findings, the researchers then developed a mathematical model to predict colony lifespan by linking it with colony size, or mass. They found that the larger colonies tended to live longer and use less energy than smaller colonies.

The research is a continuation of a 2010 study Hou and his colleagues published in the Proceedings of the National Academy of Sciences. In that paper, the researchers introduced the idea that insect societies operate like a single superorganism in terms of their physiology and life history.

Hou is first co-author of the Biology Letters article with Dr. Jonathan Z. Shik of North Carolina State University. Other contributors to the study are Dr. Adam Kay of the University of St. Thomas in St. Paul, Minn.; Dr. Michael E. Kaspari, Presidential Professor of Biology at the University of Oklahoma; and Dr. James F. Gillooly, associate professor of biology at the University of Florida.

Other researchers are taking quarter-power scaling and applying it to entire cities, to determine whether they too function as "superorganisms" in some respects, such as energy usage. For instance, says Hou, Dr. Geoffrey West, a theoretical physicist and past president of the Santa Fe Institute, and his colleagues found that "proxies of city energy usage, such as number of gas stations, total length of electric cables and so on, scale sub-linearly with the size of the city," says Hou.

"Just like the examples of and cells, between two similar people, the one living in the bigger city is more energy-efficient," Hou says. "As you can imagine, the number of gas stations per capita is smaller in New York than St. Louis, and smaller in St. Louis than Rolla, which means more people share one gas station in New York than in St. Louis, than in Rolla."

Hou, an expert in animal energetics, applies similar energy scaling laws to study how animals uptake energy during growth and how they allocate that energy to growth, health maintenance and reproduction. Recently, his focus has been on the effect of food restriction on extending the animals' life spans.

Explore further: Telling the time of day by color

Related Stories

Ant colonies shed light on metabolism

Aug 26, 2010

Ants are usually regarded as the unwanted guests at a picnic. But a recent study of California seed harvester ants (Pogonomyrmex californicus) examining their metabolic rate in relation to colony size may lead to a better ...

Study suggests theory for insect colonies as 'superorganisms'

Jan 19, 2010

New A team of researchers including scientists from the University of Florida has shown insect colonies follow some of the same biological "rules" as individuals, a finding that suggests insect societies operate like a single ...

Ant’s social network similar to Facebook

Apr 14, 2011

(PhysOrg.com) -- A recent study in the Journal of the Royal Society Interface presents findings that show that not all ants are as social as others. Similar to your friends on Facebook, some ants communicate with o ...

Recommended for you

Telling the time of day by color

9 hours ago

Research by scientists at The University of Manchester has revealed that the colour of light has a major impact on how the brain clock measures time of day and on how the animals' physiology and behavior adjust accordingly. ...

Aphrodisiac for fish and frogs discovered

14 hours ago

A supplement simply added to water has been shown to boost reproduction in nematodes (roundworms), molluscs, fish and frogs – and researchers believe it could work for humans too.

Evolution puts checks on virgin births

15 hours ago

It seems unnatural that a species could survive without having sex. Yet over the ages, evolution has endowed females of certain species of amphibians, reptiles and fish with the ability to clone themselves, ...

Humans can't resist those puppy-dog eyes

Apr 16, 2015

When humans and their four-legged, furry best friends look into one another's eyes, there is biological evidence that their bond strengthens, researchers report.

Roundworm parasite targets canine eyes

Apr 16, 2015

(HealthDay)—A small number of dogs and cats across the United States have been infected by a roundworm parasite that targets the eye, according to a new report.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.