Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

For ants, unity is strength – and health

23.11.2018

Ant social networks put a brake on disease spread - Study published in Science

When a pathogen enters their colony, ants change their behavior to avoid the outbreak of disease. In this way, they protect the queen, brood and young workers from becoming ill.


The scientists tagged thousands of ants in total to quantify all interactions between individuals and understand how colonies can protect themselves from disease.

Timothée Brütsch

These results, from a study carried out in collaboration between the groups of Sylvia Cremer at the Institute of Science and Technology Austria (IST Austria) and of Laurent Keller at the University of Lausanne, are published today in the journal Science.

High population density, as well as frequent and close contacts between individuals, contribute to a rapid spread of diseases. To protect their colonies, ants have developed disease defense mechanisms, including adaptations to their social organization.

Ants do not interact randomly with other colony members, but are organized in sub-groups according to their age and the tasks they carry out. While young worker ants, so-called “nurses”, look after the valuable brood at the center of the colony, older worker ants become foragers that collect food outside the nest. These forager ants are more exposed to pathogens.

Strengthening the fort

The researchers used a “barcode” system developed in the Keller group to follow the interactions between ants, especially to observe their behavior when disease spreads. In a first experiment, they placed digital markers on 2’266 garden ants.

Infrared cameras took an image of the colonies every half second, and so the researchers could follow and measure the movement and position of each individual, and their social interactions. The researchers showed that the ants’ subdivision into groups acts prophylactically and reduces the risk that disease spreads.

10% of the worker ants (all foragers) were then exposed to fungal spores which spread easily through contact. Comparing the ant colonies before and after pathogen exposure showed that the ants quickly detect the presence of the fungal spores and change their behavior to strengthen already existing defenses.

“The ants change how they interact and who they interact with”, explains Sylvia Cremer, “The cliques among ants become even stronger, and contact between cliques is reduced. Foragers interact more with foragers, and nurses more with nurses.

This is a response by the whole colony – also animals who are not themselves treated with spores change their behavior.” Laurent Keller adds: “This is the first scientific study that shows that an animal society is able to actively change its organization to reduce the spread of disease.”

Using a highly sensitive qPCR method established in the Cremer group, the researchers could quantify exactly how many spores an individual ant carried on its body. qPCR monitors how a targeted DNA molecule is amplified during the so-called polymerase chain reaction.

This allows researchers to draw conclusion about how much of the DNA, and by inference how much of the fungal spores, were present in the beginning.

Because the ants changed how they interact, spores transfer patterns also changed. Only few individuals received a high pathogen dose, which could cause disease. In addition, more ants received a low dose, which Cremer and her group previously showed to not cause disease but instead be protective in the face of future infections – similar to variolation in humans.

“The pathogen is distributed on many shoulders, and the ants’ immune systems can deal very well with this lower pathogen level, which provides a form of immune memory”, says Cremer.

Save the queen

The analyses also showed that the colony protects especially valuable animals. The queen, the only individual that reproduces, and the nurses, young worker ants that can still contribute many hours of work to the colony, received less of the pathogen. “In a colony, not all animals have to be protected – but the most valuable individuals should survive”, Keller explains.

The researchers also carried out a survival experiment, to see how pathogen load 24 hours after exposure correlates with death from disease. The correlation was high, says Nathalie Stroeymeyt, first author and Postdoc in the group of Laurent Keller:

“We calculated a predictive spore load for each individual ant, based on its interaction with other ants in the first 24 hours after pathogen exposure. Ants with a high predicted spore load were more likely to die nine days after exposure than ants with a low predicted spore load.” She summarizes: “Mortality was higher among foragers than among nurses. And all the queens were still alive at the end of the experiment.”

How ants collectively deal with problems, such as the risk of an epidemic, could give insights into general principles of disease dynamics, says Cremer:

“Social interactions are the routes on which diseases travel and define how epidemics may spread. Basic research on ants can help us to deeper understand epidemiological processes, which can be relevant also in other social groups.”

About IST Austria
The Institute of Science and Technology (IST Austria) is a PhD-granting research institution located in Klosterneuburg, 18 km from the center of Vienna, Austria. Inaugurated in 2009, the Institute is dedicated to basic research in the natural and mathematical sciences. IST Austria employs professors on a tenure-track system, postdoctoral fellows, and doctoral students. While dedicated to the principle of curiosity-driven research, the Institute owns the rights to all scientific discoveries and is committed to promote their use. The first president of IST Austria is Thomas A. Henzinger, a leading computer scientist and former professor at the University of California in Berkeley, USA, and the EPFL in Lausanne, Switzerland. The graduate school of IST Austria offers fully-funded PhD positions to highly qualified candidates with a bachelor's or master's degree in biology, neuroscience, mathematics, computer science, physics, and related areas. http://www.ist.ac.at

Wissenschaftliche Ansprechpartner:

Sylvia Cremer
Institute of Science and Technology Austria (IST Austria)
Am Campus 1
A – 3400 Klosterneuburg
Phone: +43 (0)2243 9000-3401
E-mail: sylvia.cremer@ist.ac.at

Originalpublikation:

Social network plasticity decreases disease transmission in a eusocial insect, Nathalie Stroeymeyt, Anna V. Grasse, Alessandro Crespi, Danielle P. Mersch, Sylvia Cremer, Laurent Keller, Science, 2018
http://science.sciencemag.org/cgi/doi/10.1126/science.aat4793

Weitere Informationen:

https://ist.ac.at/en/research/research-groups/cremer-group/ Research group of Sylvia Cremer
https://www.dropbox.com/sh/czlrqne4kdiq9w6/AADQyOplm3vkWm09yLrOfsjWa?dl=0 Additional images (credit: Timothée Brütsch)

Dr. Elisabeth Guggenberger | idw - Informationsdienst Wissenschaft

Further reports about: ants colony disease spreads fungal fungal spores spores

More articles from Studies and Analyses:

nachricht How to design city streets more fairly
18.05.2020 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

nachricht Insects: Largest study to date confirms declines on land, but finds recoveries in freshwater – Highly variable trends
24.04.2020 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Restoring vision by gene therapy

Latest scientific findings give hope for people with incurable retinal degeneration

Humans rely dominantly on their eyesight. Losing vision means not being able to read, recognize faces or find objects. Macular degeneration is one of the major...

Im Focus: Small Protein, Big Impact

In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.

Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New image of a cancer-related enzyme in action helps explain gene regulation

05.06.2020 | Life Sciences

Silicon 'neurons' may add a new dimension to computer processors

05.06.2020 | Physics and Astronomy

Protecting the Neuronal Architecture

05.06.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>