Nav: Home

Ants maintain essential interactions despite environmental flux

June 12, 2019

UNIVERSITY PARK, Pa. -- Ants adjust their social interactions to accommodate changes in population density, according to researchers at Penn State and Georgetown University. The findings suggest that ant colonies are capable of maintaining their sophisticated social organization despite potentially drastic changes in their environments.

"Ants are among the most ecologically successful groups in nature due to their complex social organization, particularly their division of labor, including food acquisition," said David Hughes, associate professor of entomology and biology. "The survival of ant colonies depends on their ability to maintain this organization. In our study, we saw remarkable resilience of ant colonies to changes in population density. This finding helps to explain ants' evolutionary success."

According to Hughes, changes in ant colony size and population density are natural occurrences. They can increase as the queen reproduces and the colony grows, and they can decrease when the colony decides to split into multiple nest sites.

"To minimize potentially adverse effects due to changes in density and to maintain social balance, ant colonies should try to actively manage the rates of their interactions," said Hughes. " Until now, however, few studies have investigated these phenomena."

The researchers manipulated the population densities of three colonies of carpenter ants by quadrupling the sizes of their nest spaces. They placed the colonies inside wooden camera boxes fitted with infrared lights so they could film the ants under natural dark nesting conditions. The ants were able to leave the nests at any time to enter foraging areas.

The team manually identified the position in the nest of each ant at every point in time -- equivalent to more than 6.9 million data points -- to investigate whether the increased nest space influenced the spatial organization of the insects. The researchers found that the ants' positions relative to the others was similar regardless of the population density. When population density was lower, ants simply were separated further in space from each other.

Next, the researchers examined 3,200 ant interactions to analyze whether the increase in nest space influenced their task performance -- especially related to trophallaxis, or the transfer of foods from ant to ant. The team's results appeared May 2, 2019, in eLife.

"As a statistician, I built statistical models that captured how individual ants move within their nests, and how and when they chose to engage in important social behaviors like trophallaxis," said Ephraim Hanks, associate professor of statistics, Penn State. "These analyses helped to explain how ant populations maintained high levels of community interactions even after their spatial environment was changed."

Indeed, the team found that -- contrary to its expectations, which were that ant interactions would decrease with decreasing population -- ant interactions actually did not change with decreased density.

"Our results showcase the kinds of behavioral mechanisms ant colonies apply to achieve social homeostasis in the face of disturbance," said Hughes. "Specifically, ants actively regulate their spatial distribution and interaction behaviors in a way that allows them to maintain critical elements of their social interaction patterns -- such as food and information exchange -- in spite of drastic changes in their environment."

"This work shows that social species like ants can maintain levels of social connection and interaction even when their environment changes drastically," said Hanks. "As social interactions are a critical driver of the spread of infectious disease, our work shows that changing spatial environments, such as how cities or businesses are laid out, may have little or no effect on the spread of infectious disease, as social species may change their movement patterns to conserve community interactions."
-end-
Andreas Modlmeier, former postdoctoral fellow and a leader of the study, and Ryan Bringenberg, former undergraduate student, Penn State; Ewan Colman, postdoctoral fellow, Georgetown University; and Shweta Bansal, assistant professor of biology, Georgetown University.

The National Science Foundation supported this research.

Penn State

Related Infectious Disease Articles:

Infectious disease in marine life linked to decades of ocean warming
New research shows that long-term changes in diseases in ocean species coincides with decades of widespread environmental change.
What makes some people more receptive to the idea of being vaccinated against infectious disease?
Fear, trust, and the likelihood of exposure are three leading factors that influence whether people are willing to be vaccinated against a virulent disease, according to a new study in the journal Heliyon, published by Elsevier.
Can we feed 11 billion people while preventing the spread of infectious disease?
A new article published in Nature Sustainability describes how the increase in population and the need to feed everyone will give rise to human infectious disease, a situation the authors of the paper consider 'two of the most formidable ecological and public health challenges of the 21st century.'
Coat of proteins makes viruses more infectious and links them to Alzheimer's disease
New research from Stockholm University and Karolinska Institutet shows that viruses interact with proteins in the biological fluids of their host which results in a layer of proteins on the viral surface.
Climate change responsible for severe infectious disease in UK frogs
Climate change has already increased the spread and severity of a fatal disease caused by Ranavirus that infects common frogs (Rana temporaria) in the UK, according to research led by ZSL's Institute of Zoology, UCL and Queen Mary University of London published today in Global Change Biology.
More Infectious Disease News and Infectious Disease Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...