A group of ‘friend or foe’ scent molecules have been isolated from colonies of Argentine ants. Researchers writing in the open access journal BMC Biology identified and synthesized the scents, describing how applying them to worker ants resulted in attacks from their former colony-mates.
Neil Tsutsui and colleagues, from the University of California, Berkeley, USA, worked with a team of researchers from the University of California, Irvine to carry out the ant experiments. He said, “Chemical signaling is the most ancient mode of communication, and it is still used in some form by all organisms. The elaborate social systems of ants are largely regulated by chemical signals, but very little is known about the chemical labels that define colony membership”.
Tsutsui and his colleagues first identified candidate molecules for colony-mate recognition by looking for chemical differences between ants that fought. They then synthesized seven of these molecules in pure form and tested their ability to induce aggression among worker ants from the same colony. Finally, they tested the behavioral responses to changes in the quantity of these cues, and how combinations of different scents affected the expression of aggression toward treated colony-mates.
Speaking about the discovery, Tsutsui said, “The fact that application of these chemicals can make formerly friendly animals flare their mandibles, recoil, bite, grab and use chemical defenses suggests that we have provided some of the first insights into the identity of ant colony-mate recognition cues. Future studies will be able to apply these findings to exploration of social evolution, sensory ecology, neurophysiology and invasion biology”.
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