Farmers in tropical forests are training ants to kill off bigger pests

Farmers who have harnessed the collective power of the humble ant have proved more successful at controlling the pests that ravage their crops than those using chemicals, according to new research.

A colony of reddish brown ants

Armed only with the most rudimentary equipment, farmers in Asia, Africa and Australia have caught, cultivated and trained colonies of ants to patrol tropical forests to kill off bigger pests – with remarkable results.

Red harvester ants eating a caterpillar

Said the lead researcher,

“Ants are great hunters and they work cooperatively. When an ant finds its prey, it uses pheromones to summon help from other ants in the nest. By working together, they can subdue even large pests.”

A study of cashew nut crops in Australia found “pest control by ant” was nearly 50 per cent more successful than if the farmer used conventional pesticides. The quality of the crop was also higher, leading to huge increase in income for the farmer.

Weaver ants attacking/hunting a tortoise beetle

In other cases, farmers were able to mount effective defences against pests by hanging ant nests from carrier bags from trees in a tropical forest and feeding the colony sugar solution to help it to develop. The farmers then hooked up string between the trees to create a successful defence system, with a network of ant aerial walkways in the forest canopy at minimal cost.

Weaver ants collaborating to pull nest leaves together

A little careful husbandry – including pruning trees to ensure rival colonies of weaver ants did not fight – and watering  in the dry season would lead to all-year-round protection. Studies of 50 pest species showed that ants protected crops, including cocoa, citrus and palm oil, at least as efficiently as chemicals.

Ants around a drop of honey, an example of the complex collective behavior in an ant colony

Ants live on every continent except Antarctica, with some estimates suggesting that the mass of all ants on Earth is similar to that of humans.  Their cooperative working means that they act as super-organisms, and a single colony can weigh several kilogrammes.

(All images - credit: Wikimedia Commons under Creative Commons licence)