Ants are possibly most famous for wrecking picnics – but new research shows that ants may be an important tool for managing insect pests on crops, perhaps even more effectively than chemical insecticides.

The study combined results from hundreds of other studies published within the last 35 years. In all these studies, ants were removed from one treatment, but allowed to roam freely in another.

Overall, the researchers found that having ants present in cropped fields and orchards tended to reduce the number of insect pests. The more diverse the mix of ant species, the bigger the anti-pest effect.

There were a few “buts,” though. The biggest one is that ants actually protect a handful of pest species – aphids, whiteflies, and mealybugs – that produce sugary secretions called honeydew. The ants herd and tend these species to gather that energy-rich food source. When ants are present, the numbers of these honeydew-producing pest species actually increase.

Having more ants around also tended to decrease the number of other beneficial insects that might have preyed on insect pests.

However, even with ants increasing the number of aphid-like pests, and driving off other beneficial insects, the overall finding was that crop damage from insect pests was reduced, and crop yield increased, when ants were present.

Some ant species, the researchers wrote, were as effective, or even more effective, than chemical insecticides – and at lower cost.

Many of these studies were conducted in tropical regions with warm-weather crops, so the concept is far from fully tested for Oklahoma. Also, many of us might be happy to see the insecticide bill go up if it meant we could get rid of fire ants. Still, if you give this a try, we’d be interested to hear how it goes!

The study was published in Proceedings of the Royal Society B.