Ozone Can Make Ants Attack Their Own Nestmates
Ant colonies run on smell. Nestmates recognise each other by a chemical signature, and anything that smells wrong is treated as an intruder. A new study from the Max Planck Institute for Chemical Ecology asks what happens when air pollution changes that smell.
The researchers, led by Nan-Ji Jiang and Bill Hansson with Markus Knaden, exposed six ant species to 100 parts per billion of ozone for 20 minutes, a level often measured in affected areas in summer, and then returned the ants to their colonies. Five of the six species attacked or threatened the ozone-exposed nestmates. The exception was the clonal raider ant, Ooceraea biroi, which showed no aggression, perhaps because it reproduces clonally and has no queen.
The mechanism is neat. Ants carry small amounts of alkenes in their colony odour, and ozone breaks the carbon-carbon double bonds in those molecules. Alkanes, which make up most of the signature, are not affected. Gas chromatography on individual ants confirmed the shift in the alkenes.
There were longer-term effects too. In ozone-polluted colonies of O. biroi, adults stayed farther from their larvae and many larvae died. Since ozone was largely ruled out as a direct cause, the authors suspect that chemical communication between adults and larvae had been disrupted.
What I take from this is how fragile the invisible side of colony life is. The paper, published in PNAS in 2026, suggests other social insects such as bees could be affected as well. It is also a quiet reminder to anyone keeping a colony indoors to think about air quality around the nest.
Source: Phys.org (Max Planck Society)
The researchers, led by Nan-Ji Jiang and Bill Hansson with Markus Knaden, exposed six ant species to 100 parts per billion of ozone for 20 minutes, a level often measured in affected areas in summer, and then returned the ants to their colonies. Five of the six species attacked or threatened the ozone-exposed nestmates. The exception was the clonal raider ant, Ooceraea biroi, which showed no aggression, perhaps because it reproduces clonally and has no queen.
The mechanism is neat. Ants carry small amounts of alkenes in their colony odour, and ozone breaks the carbon-carbon double bonds in those molecules. Alkanes, which make up most of the signature, are not affected. Gas chromatography on individual ants confirmed the shift in the alkenes.
There were longer-term effects too. In ozone-polluted colonies of O. biroi, adults stayed farther from their larvae and many larvae died. Since ozone was largely ruled out as a direct cause, the authors suspect that chemical communication between adults and larvae had been disrupted.
What I take from this is how fragile the invisible side of colony life is. The paper, published in PNAS in 2026, suggests other social insects such as bees could be affected as well. It is also a quiet reminder to anyone keeping a colony indoors to think about air quality around the nest.
Source: Phys.org (Max Planck Society)
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