Tuesday, October 9, 2012

Busy Fall Ants

Edward O. Wilson is one of my scientist heroes, and he has studied ants for most of the 83 years of his life.  As a child, he loved to go outside and observe ants for hours because they exhibit such a variety of behaviors.  E. O. Wilson eventually became the world's leading myrmecologist (ant expert), as well as an expert on ecology, animal behavior and conservation biology.  Thanks to him, I know some really amazing things about ant behavior, and I always think of him when I observe ants.
A foraging ant.
The ants at our outdoor classroom are busy, busy, busy this time of year.  Frost is coming soon, and the ants are foraging for their last bits of food to help get them through the cold weather coming our way.  If you stop and observe the rocks around the pond, you will start to see some patterns in the ants' behaviors as the ants bustle around in a mad rush to get ready for winter.  Below are some patterns in ant behavior that I observed.
An ant and her shadow.
The ant above was exploring to find food, also known as foraging.  Any ant exploring on its own in a zig-zag or random fashion is most likely foraging for food.  When the ant finds food, it will pick up the food and bring its food back to the ant's nest to share with the other ants in its colony.  If there is more food than it can carry, the ant will do something incredible.  It will leave a scent trail on its return to the nest to signal to its nest mates to go and get the rest of the food!  How amazing that these tiny creatures can communicate such complex information to each other.
Ants following a scent trail.
Ants are social insects that live in colonies.  The ants in a row in the picture above are interacting as a social group by following a common scent trail.  Either they are all going to get food or they are moving their colony.  Ants usually maintain a nest in a space in or near the ground.  The nest stores their food and eggs.  The ants in the picture above are all sisters!  I know this because all worker ants are female and are sisters.  The sisters work together to keep the colony alive and take care of their mom, the queen.  The queen stays in the ants nest and lays eggs.  If you look closely at a line of ants, you might be able to see if they are carrying bits of food or eggs.  If they are carrying ant eggs, they are moving the colony.  There is a colony of ants outside my back door that moves its nest every time it rains: from under the flower pot in dry weather to under a loose brick when it's rainy.  They never seem to get tired of carrying eggs around.
Ants deciding if they are friends or enemies.
If you observe a line of ants, you will probably notice ants are going in both directions, like in the picture above.  That means the ants run into each other.  Every time an ant runs into another ant, it needs to determine if the other ant is a friend or an enemy.  Enemy ants must be run off the territory or killed and eaten, and friendly ants must be allowed to pass.  Ants don't recognize each others' faces; rather, they smell each other with their antennae.  It takes just a flash for the ants to touch antennae, recognize each other, then head on their way. 

Ants are extremely important creatures on Earth.  They live in the soil and on trees and other plants, and they help recycle nutrients in ecosystems.  Ants build soil, eat pest organisms, and provide food for other insects and for birds.  Some plants are pollinated by ants, and some seeds are dispersed by them too.  E. O. Wilson has estimated that ants account for about the same amount of mass on Earth as humans do! I wonder which has had a greater impact on our planet.  I know humans have built cities and houses and reshaped the ecosystems, but ants have built the soil that all other terrestrial ecosystems are built on.

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