Ant Talk

Apr 19 2011 Published by under Biology & Environment

Ant on a mustard flowerWhen a wood thrush flew by the Trailhead mound carrying a grasshopper to her own nest and dropped part of the crushed insect to the ground, a patrolling worker found it in less than a minute and triggered a chain action. The worker examined the grasshopper, tasted it briefly, then ran back to the nest entrance. On the way, she touched the tip of her abdomen repeatedly to the ground, laying down a thin trail of chemicals. Entering the nest, she rushed up to each nest mate she passed, brushing her face close to theirs. With their antennae, her nest mates detected both the trail substance and the smell of grasshopper. The signals now proclaimed, Food. I have found food. Follow my trail! Soon a mob of ants ran out, followed the trail, and gathered around the delicious grasshopper haunch.
~ From E.O. Wilson's "Trailhead"

When I think of ants it's with a mixture of fascination and loathing.

Loathing because of the seemingly constant battle required to keep them from taking up residence in my kitchen. It's not just the unpleasantness of having to remove all the contents of my cabinets to figure out how the ants are getting in.  It's the lingering sensation after handling ant-covered bowls and plates or wiping down ant-strewn counters that the little buggers are still crawling on me.  Intellectually I know it's unlikely they can cause any real harm, but just thinking about it gives me the creepy-crawlies.

But out in the wild - or at least my back yard - ants are really interesting to watch, especially when scouts lead their colony-mates to a food source or mobilize when their colony is in danger. Clearly while not particularly clever as individuals, communication between colony members allows them to function effectively as a group.

Evolutionary biologist E.O. Wilson is one of the world's leading experts on ants. Here he explains at World Science Festival how ants use chemical signals communicate:

The quote at the beginning of this post is from E.O. Wilson's history of an ant colony - "Trailhead" - published in the New Yorker. Wilson's anthropomorphic descriptions of ant communication work pretty well as fiction, but he may be oversimplifying what happens in an ant colony.

For more detailed look on the complexities of how an ant colony functions check out Stanford biologist Deborah Gordon's TED talk about her research on harvester ant colonies in the Arizona desert:

(note: you can view the video with captions on the TED talk page)

The "haphazard" interactions she's observed sound a lot messier as a form of communication than the chemical "statements" described by Wilson.

Why does that matter? Figuring out the details of how ants are directed to perform specific tasks could be used to develop ways of naturally controlling invasive ant populations or preventing home invasions with some sort of "Danger, keep out!" signal. That's a result I'd like to see.

Top Image: ant on a mustard flower by me

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