Tuesday, December 31, 2013

The "Rheology" of Fire Ants

The New York Times had a fun video a couple of weeks ago showing that groups of fire ants can show viscoelastic behavior. By clinging to each other, they show solid-like behavior, but by releasing that grip, they can flow like a liquid. While viscoelastic behavior is much more common than most people realize, this is the first time it has been observed in groups of living things. (Note that the article states that it is a first for "living things" which is clearly incorrect. As far as I know, all living things show viscoelastic behavior within at least some parts of themselves, whether it is the viscoelastic behavior of cells, mucosal fluids, blood, etc.) Being that ants are macroscopic beings, their flow would show characteristics of a granular flow rather than fluid flow, a subtle but sometimes important difference.

What is left undiscussed in the video is how the ants are able to communicate what behavior is desired at any given moment. Each ant can't be deciding on its own whether to grip or release; there has to be a rapid, universal signaling mechanism or else it would be chaos. I find this, along with the similar phenomena of flocking behavior and quorum sensing to be some of the most fascinating aspects of biology.


Anonymous said...

That's true, the rheology of these ants maybe linked to their individual behavior - like swarm intelligence observed in insects, which are a result of individual insects being self-organized. It would be interesting to know what the particular 'cues' for these ants are to show such behavior. Maybe they are only linked to a simple parameter such as the stress or strain rate applied on these ants.

thivithivi said...
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thivithivi said...

The rheology of fire ants is the study of their flow and deformation properties. Fire ants are able to form aggregations that can behave like solids, liquids, or even gels, depending on the conditions. This ability is due to the way that the ants interact with each other. They form temporary connections using their legs and antennae, which allows them to transmit forces and resist deformation. The rheology of fire ants is a complex topic that is still being studied by scientists. However, it is clear that this ability plays an important role in the ants' ability to survive and thrive.
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