Because cocaine causes honey bees to dance more an altruistic behavior the researchers believe their results support the idea that there is a reward system in the insect brain, something that has never before been shown.
To determine whether the cocaine was merely causing the bees to move more or to dance at inappropriate times or places, the researchers conducted a second set of experiments. These tests showed that non-foraging honey bees don't dance, even when exposed to cocaine. They showed that foragers on cocaine do not move more than other bees (except when dancing), and that they do not dance at inappropriate times or in locations other than the dance floor.
The researchers also found that the bees on cocaine do not dance every time they go on a foraging excursion. And, most important, their dances are not distorted.
"It's not like they're gyrating wildly on the dance floor out of control," Robinson said. "This is a patterned response. It gives distance information, location information. That information is intact."
In a final experiment that also shows parallels to human behavior, the researchers found that honey bees on cocaine experience withdrawal symptoms when the drug is withheld.
"This study provides strong support for the idea that bees have a reward system, that it's been co-opted and it's now involved in a social behavior, which motivates them to tell their hive mates about the food that they've found," Robinson said.
The findings also indicate that honey bees will make good subjects for substance-abuse research, he said.
|Contact: Diana Yates, Life Sciences Editor|
University of Illinois at Urbana-Champaign