Natures wonders: ants control aggression II (Introduction)

by David Turell , Tuesday, May 26, 2020, 22:30 (1640 days ago) @ David Turell

They identify foreign scents before an attacK:

https://cosmosmagazine.com/biology/ants-don-t-need-anger-management?utm_source=Cosmos+-...

"At a time when humans are expressing increased outrage, we might have something to learn from ants.

"Researchers have discovered they use a clever, precise mechanism to switch on aggression towards intruders from other colonies to defend their own,

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"Ants have been around for tens of millions of years and have complex, highly organised social structures that help their colonies thrive; telling nestmates apart from non-nestmates is a key aspect of this.

“'Accepting friends and rejecting foes is one of the most important decisions an ant worker must make,” says Stephen Ferguson from Vanderbilt University.

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"This new research has found that they need to smell and interpret fragrant compounds on intruder ants to “unlock” aggressive behaviour and protect their nest, which senior author Laurence Zwiebel refers to as a “coat of many odours”.

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"Ants with normal receptors recognised and fought with those from other colonies, but ants with blocked or overactivated receptors showed dramatically reduced aggressive behaviour.

"The aggression is thus triggered by what the researchers term a “lock and key” mechanism.

“'The tumblers of the lock are the odourant receptors, and the teeth of the key represent the mixture of odourants that an ant might encounter on the cuticle of a non-nestmate,” Ferguson explains.

“'Neither a toothless key (antagonist) nor a rake (agonist) are sufficient to unlock aggression. Rather, the presence of a particular set of teeth on the key are required to elicit aggression between non-nestmates.”

"The tolerant stance appears to be the norm, and the insects will only become aggressive if this very precise signal is correctly “decoded” by their smell receptors, proving a long-held theory.

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“'Put another way, ants, which have some of the most sophisticated and successful social structures in biology, do not practice a ‘shoot first and ask questions later’ social policy.'”

Comment: Note this is very tightly controlled automatic response, no thought involved, and indicates most animal responses are quite automatic.

This article on ant aggression adds a little:

https://www.scientificamerican.com/article/smell-receptors-activate-ant-aggression/

"Scientists have long observed ants deftly navigating through crowds, attacking only individuals that might be hostile. New research confirms how smell receptors on the insects' antennae hold the key to this selective violence: without them, ants are socially blind and will not attack.

“'The current consensus was aggression between ants follows a simple rule: if [an ant] smells something different from the home colony, attack,” says Laurence Zwiebel, a co-author on the new study and a biologist at Vanderbilt University. But the new research shows it is not that simple. Ants hold off on attacking if they cannot smell anything—or even if they do not recognize a scent. “Rather a precise signal present on the non-nest mate must be correctly decoded for aggression to occur,” Zwiebel says.

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"Ants have more than 400 odorant receptors, and Zwiebel says a next step is to determine which of them must function correctly to decode an enemy's smell. (For this study, researchers dampened or excited all of them.)"

Comment: More evidence of ants' automatic responses.