Ants rely heavily on smell, particularly smelly hydrocarbons. It’s a chemical ID card of sorts that tells every member of the colony who belongs and who is an intruder. A new study from researchers at the oft-cited Max Planck Institute, published in the Proceedings of the National Academy of Sciences, shows that human air pollution is shredding up that ID system and sending ant colonies spiraling into civil wars.Ants use stable alkalines as a base for their scent, and this alkaline-based perfume, which is specific to each colony, allows for individual recognition. The problem is with ozone, not to be confused with the Ozone Layer. Ozone is a common urban pollutant that can easily degrade alkalines. You can see where this is headed.Researchers found that when ants from six different species were exposed to 100 parts per billion of ozone, a level commonly reached in major cities during the summer, their chemical signatures were obliterated in as little as 20 minutes. This was a full-on catastrophe for ant colonies. When worker ants exposed to ozone returned home, their own colony buddies couldn’t recognize them anymore. In five of the six species tested, the colony reacted with immediate aggression, threatening and attacking their own citizens. In separate experiments, urban-level ozone corrupted care behavior deep inside the colony, leading to the death of larvae.Who Cares About an Ant Civil War?You might think, well, they’re just ants. They’re small. Insignificant. But ants represent a huge portion of the Earth’s biomass and do all of the dirty work that we take for granted, like tilling soil, dispersing seeds, and cleaning out ecosystems. Climate change and pesticides get a lot of the blame for population declines in all sorts of animal species, insects included, but this research is saying that we are also accidentally sabotaging the social fabric of ant species without even realizing it, and all by altering the chemical composition of the air.By making ants smell different, we are accidentally turning their hyper-functional, ultra-cooperative societies paranoid and aggressive. Of course, what did we expect when we started changing the chemical composition of the natural world?The post Humans Are Causing Ant Colony Civil Wars appeared first on VICE.