ANTS promptly dispose off their dead to protect the colony from infection. But how do they know when an ant is dead? The understanding among entomologists was that dead ants release chemicals created by decomposition (like fatty acids) signalling death to the living ants.
But now University of California Riverside (UCR) entomologists working on Argentine ants provide evidence of a different mechanism for how necrophoresis — the removal of dead nestmates from colonies — works.
Researchers report that
both living and dead ants have 'death chemicals' continually, but live
ants have something more, the ‘life chemicals’. When an ant dies,
its life chemicals dissipate or are degraded, and only the death
chemicals remain. "It’s because the dead ant no longer smells
like a living ant that it gets carried to the graveyard, not because
its body releases new, unique chemicals after death," said Dong-Hwan
Choe, study co-author, working for a doctoral degree with Michael
Rust, professor of entomology at UCR. Choe explained that the research
paper’s results resolve a conundrum of long-standing in animal
behaviour and correct a misinterpretation of previous results that has
become both popular and widespread in literature, said an UCR release.
"There is no mistaking that it is the dissipation of chemical
signals associated with life rather than the increase of a
decomposition product ‘death cue’ that triggers necrophoric
behaviour by Argentine ants," he said. These findings were
published online in the early edition of the Proceedings of the
National Academy of Sciences. — IANS