Most insect behavior is genetically programmed, or innate. A caterpillar with no prior experience or instruction can still spin a silken cocoon. But can an insect change its behavior as a result of its experiences? In other words, can insects learn?
You won't see one graduating from Harvard anytime soon, but indeed, most insects can learn. "Smart" insects will change their behaviors to reflect their associations with and memories of environmental stimuli.
For the simple insect nervous system, learning to ignore repetitive and meaningless stimuli is a fairly easy task. Blow air on a cockroach's rear end, and it will flee. If you continue to blow air on the cockroach over and over, it will eventually conclude that the sudden breeze is no cause for concern, and stay put. This learning, called habituation, helps insects save energy by training them to ignore what is harmless. Otherwise, the poor cockroach would spend all its time running away from the wind.
Imprinting occurs during a brief period of sensitivity to certain stimuli. You've probably heard stories of baby ducks falling in line behind a human caretaker, or of nesting sea turtles that return to the beach where they hatched years earlier. Some insects also learn this way. Upon emerging from their pupal cases, ants notice and retain the scent of their colony. Other insects imprint on their first food plant, showing a clear preference for that plant for the remainder of their lives.
Like Pavlov's dogs, insects can also learn through classical conditioning. An insect exposed repeatedly to two unrelated stimuli will soon associate one with the other. Wasps can be given food rewards each time they detect a certain scent. Once a wasp associates food with the smell, it will continue to go to that scent. Some scientists believe trained wasps may replace bomb and drug sniffing dogs in the near future.
A honeybees demonstrates its ability to learn each time it leaves its colony to forage. The bee must memorize patterns of landmarks within its environment to guide it back to the colony. Often, she is following the instructions of a fellow worker, as taught to her through the waggle dance. This memorization of details and events is a form of latent learning.
Sources:
- The Handy Bug Answer Book, by Gilbert Waldbauer
- Elements of Behavior, North Carolina State University
