Tiny ants can teach us a thing or two about pesticides


Washington : Ants are not only industrious and dedicated, they are quite capable of keeping their gardens pest free, a feat still beyond human agriculturalists.

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And to cap it all, they have been doing it for more than 50 million years. Leaf-cutter ants put their freshly-cut leaves in gardens where they grow a special fungus that they eat.

New material is continuously incorporated into the gardens to grow the fungus and old material is removed by the ants and dumped away from the colony.

The ants are also adept at weeding. The presence of a microbial pest triggers a flurry of activity among worker ants as they begin to comb through the garden. As soon as they find the pathogenic ‘weeds’, the ants pull them out and discard them.

“Since the ant gardens are maintained in soil chambers, they are routinely exposed to a number of potential pathogens that could infect and overtake a garden. In fact, many of the ant colonies do become overgrown by fungal pathogens, often killing the colony,” said Cameron Currie, professor at the University of Wisconsin-Madison.

“Scientists have shown that a specialised microfungal pathogen attacks the gardens of the fungus-growing ants. These fungi directly attack and kill the crop fungus, and can overrun the garden in a similar fashion to the way weeds and pests can ruin human gardens.”

Some worker ants were found to have a white wax-like substance across their bodies. When they looked at it under a microscope scientists discovered that this covering was not a wax, but a bacterium!

These bacteria are part of the group actinobacteria, which produce over 80 percent of the antibiotics used by humans. The bacteria produce antifungal compounds that stop the microfungal pathogen from attacking the garden.

This discovery was the first clearly demonstrated example of an animal, other than humans, that uses bacteria to produce antibiotics to deal with pathogens, said a Wisconsin-Madison release.

These findings were published in the November issue of Microbiology Today.