Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Orientation of Desert Ants: Every Cue Counts

09.03.2012
Foraging desert ants always find their way back to the nest, even when it is only marked by a magnetic cue, vibration, or carbon dioxide

Desert ants have adapted to a life in a barren environment which only provides very few landmarks for orientation. Apart from visual cues and odors the ants use the polarized sunlight as a compass and count their steps in order to return safely to their home after searching for food.


Cataglyphis noda ants approaching their nest entrance − a small hole in the ground of an experimental tube. Max Planck Institute for Chemical Ecology/Badeke

In experiments with ants of the genus Cataglyphis in their natural habitats in Tunisia and Turkey, behavioral scientists of the Max Planck Institute for Chemical Ecology in Jena, Germany, have now discovered that ants can also use magnetic and vibrational landmarks in order to find their way back to their nest − a small hole in the desert ground.

In addition, carbon dioxide produced by their nestmates’ breathing also helps homing ants to pinpoint their nest entrance. Hence, the ants’ navigational skills prove enormously adaptable to their inhospitable environment.

Returning to the wrong nest can be lethal
Path integration is a fascinating mechanism that ants use for orientation. It combines counting the steps after leaving the nest with determining the direction by using polarized sunlight. This method, which helps the insects to return to their nest, is an important survival formula in the barren environments of deserts. However, the path integrator is error-prone. Therefore ants also use landmarks in order to find home quickly and unerringly: Visual as well as olfactory landmarks serve as important cues. For ants, it is a question of life and death to find the right nest because they may be killed or at least attacked by resident ants if they enter the wrong nest accidentally.

Vibration or magnetism

It is known from leaf-cutting ants that they use vibrational signals for communication. That ants − like birds − also sense the earth’s magnetic field, becomes more and more likely. Therefore, the researchers in Markus Knaden’s lab, behavioral scientists in the Department of Bill Hansson at the Max Planck Institute for Chemical Ecology, wanted to find out whether desert ants − adapted to landscapes providing a minimum of cues − are able to use magnetism and vibrational signals in the absence of other landmarks. “We were very surprised that this is actually the case,” says PhD student Cornelia Buehlmann, who performed the experiments. Trained ants of the species Cataglyphis noda pinpointed their nest without any problem if a battery-powered vibrational device was buried next to the nest entrance so that the ants could localize their nest by using the vibrational landmark. To exclude electromagnetic effects of the device, experiments were performed using the vibrational device without contact to the ground. The result: The ants behaved like their untrained conspecifics. They wandered around aimlessly. If two strong neodym magnets generating a magnetic field of about 21 millitesla (the earth’s magnetic field was, for comparison, only 0.041 millitesla) were placed above ground next to the nest, trained ants again found their home without any problems.

The experiments demonstrated the desert ants’ highly sensitive reaction to vibrational signals. However, it is unknown which sense is involved in the orientation using the artificial magnetic field around the nest. “This doesn’t mean that ants have a kind of sensory organ for the detection of magnetic fields. Their behavior could also be caused by abnormal neural electrical signals due to the strong magnetic field which were memorized by the ants,” says Knaden. Anyhow, neither vibrations nor strong magnetic fields are likely present in the natural vicinity of nest entrances. Therefore it is really astonishing that ants “remember” vibrations or a changing magnetic field as nest landmarks. Ants which have adapted to extremely inhospitable habitats seem to be remarkably flexible in terms of using all senses for navigation.

CO2 as an olfactory landmark

Carbon dioxide produced by the ants’ breathing is an olfactory signal that is constantly present at the nest entrances. That desert ants of the species Cataglyphis fortis use the CO2 plume in order to return to their home could now be shown by experiments performed in Tunisia. The ants ran upwind along the nest plume when the CO2 concentration was not too high and corresponded with the typical plume concentration in the nest vicinity. However, CO2 is released by all the nests and therefore all nests smell the same. Therefore the question is: How can ants recognize their own nest when all smell like home? “We could show in a series of experiments that ants primarily rely on path integration,” explains Cornelia Buehlmann. If ants were released in the close vicinity of their own nest by hand after they had walked to a feeding place, they avoided following the original nest plume of their own nest: The olfactory signal and the number of footsteps did not coincide. In order not to lose their lives in a foreign nest, ants trust path integration more than the chemical signal CO2. They only follow the nest plume when path integration tells them that they are close to home. [JWK/AO]

Original Publications:

Cornelia Buehlmann, Bill S. Hansson, Markus Knaden: Desert ants learn vibration and magnetic landmarks. PLoS ONE 7(3): e33117. DOI:10.1371/journal.pone.0033117

Cornelia Buehlmann, Bill S. Hansson, Markus Knaden: Path integration controls nest-plume following in desert ants. Current Biology, Online First, March 8, 2012; DOI: 10.1016/j.cub.2012.02.029

Further Reading:

Steck, Kathrin: Just follow your nose: homing by olfactory cues in ants. Current Opinion in Neurobiology (2011), DOI:10.1016/j.conb.2011.10.011

Further Information:

Dr. Markus Knaden, +49 3641 57 1421, mknaden@ice.mpg.de
Picture Material:

Angela Overmeyer M.A., Tel. 03641 - 57 2110, overmeyer@ice.mpg.de
or Download via www.ice.mpg.de/ext/735.html

Dr. Jan-Wolfhard Kellmann | Max-Planck-Institut
Further information:
http://www.ice.mpg.de/ext/735.html

More articles from Life Sciences:

nachricht New yeast species discovered in Braunschweig, Germany
13.12.2019 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH

nachricht Saliva test shows promise for earlier and easier detection of mouth and throat cancer
13.12.2019 | Elsevier

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Virus multiplication in 3D

Vaccinia viruses serve as a vaccine against human smallpox and as the basis of new cancer therapies. Two studies now provide fascinating insights into their unusual propagation strategy at the atomic level.

For viruses to multiply, they usually need the support of the cells they infect. In many cases, only in their host’s nucleus can they find the machines,...

Im Focus: Cheers! Maxwell's electromagnetism extended to smaller scales

More than one hundred and fifty years have passed since the publication of James Clerk Maxwell's "A Dynamical Theory of the Electromagnetic Field" (1865). What would our lives be without this publication?

It is difficult to imagine, as this treatise revolutionized our fundamental understanding of electric fields, magnetic fields, and light. The twenty original...

Im Focus: Highly charged ion paves the way towards new physics

In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.

Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...

Im Focus: Ultrafast stimulated emission microscopy of single nanocrystals in Science

The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.

Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...

Im Focus: How to induce magnetism in graphene

Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.

Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Supporting structures of wind turbines contribute to wind farm blockage effect

13.12.2019 | Physics and Astronomy

Chinese team makes nanoscopy breakthrough

13.12.2019 | Physics and Astronomy

Tiny quantum sensors watch materials transform under pressure

13.12.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>