Ants Come Marching One by One
Why do dogs sniff their owners?
Dogs identify their owners more by their scent than their good looks. Scent is a powerful tool of recognition for many species. Ants communicate using chemical messages (scents) that biologists call pheromones. Have you noticed that ants play "follow the leader" when they find food? One ant finds a bit of food, and all the other ants follow the exact same path to get to the snack. This activity shows why.
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Here's What You Do
1. Draw a circle about 5" across. Around this circle, draw four more circles, each one an inch larger, so that you have a circle surrounded by four circles.
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2. Cut along each line. Remove the middle circle. You now have four rings.
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3. Lightly tape the rings together.
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4. Find some ants outdoors. Place a drop of honey near the ants.
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5. Surround the honey drop with the rings. Tape down the outer and inner edges of the rings.
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6. Soon after the first ant tastes the honey, you'll have a trail of ants from the anthill to the honey. Notice that all the ants are following the same path. The first ant made a scent trail that the other ants follow.
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Credit: Photograph by
Tom Deerinck, NCMIR.
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7. Remove the innermost ring to take away part of the scent trail. How do the ants react?
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8. After the ants have found their way to the honey again, remove the next two inner rings. How do the ants react to the bigger gap in their trail?
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What's Going On?
An ant, returning to her nest from a source of food, marks her trail with a scent that other ants follow. This kind of scent, called a pheromone, causes animals to behave in a certain way.
Every ant that returns to the anthill with food marks her trail with pheromones. When the honey is all gone, the ants stop marking the trail. The trail disappears and the ants stop returning to the spot where the honey used to be.
Ants produce many different pheromones. Each one carries a different message. All the work in the anthill, from caring for the eggs to taking dead ants out to the rubbish heap, is controlled by pheromones.
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TAKE PICTURES, OR MAKE DRAWINGS OF THE ANTS TRAIL AND ADD THEM TO BACKYARD JUNGLE!
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