Insects' detection of mammalian bad breath helps them survive, study says

And you thought you had a sensitive nose. Recent research has shown that aphids, those tiny, green, crop-consuming insects that farmers have little love for, can smell bad breath in time to avoid being eaten.

The study, published in the journal Current Biology, found that pea aphids are acutely sensitive to the humidity of mammalian breath, allowing them to avoid accidentally being eaten by plant-consuming animals.

To determine if halitosis alerts aphids to the presence of incidental predators at all, researchers at the University of Haifa allowed a goat to consume alfalfa plants covered with aphids.

To prevent their own breath from changing the experiment’s conditions, the researchers wore snorkels.

After controlling for movement, shadows, and air humidity, the team found that breath itself cues the aphids to abandon a plant. While they theorized that carbon dioxide was the trigger, ultimately they determined that the heat and humidity of breath alerts the insects to danger.

Bad breath can similarly alert humans to disease. Halitosis in human mouths can be cause by gingivitis, tooth decay, lung diseases, sinusitis, or even excess bacteria in the mouth.

To keep breath smelling fresh and neutralize halitosis, individuals may consider rinsing the mouth with a specialty breath cleanser, along with the recommended twice daily brushing and periodic flossing.