Courtesy Mark RyanOne of the strangest behaviors observed in nature is the honey bee “waggle dance”. Foraging bees use this get-down-get-funky display to communicate to their hive mates the discovery of a new food source. It usually takes place whenever the food is of a high quality or when the hive’s pantry is growing bare. The dance is performed on a special “dance floor” in the hive and is a way for the foragers to let the other bees know what’s been found and how to get there.
“The honey bee dance is this incredibly complex set of activities,” said University of Illinois entomology and neuroscience professor Gene Robinson. “It’s a very integrated communication system, very elaborate and very elegant, one of the seven wonders of the animal behavior world.”
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Robinson and his colleagues wondered what motivated such behavior in foraging honey bees. Did they experience some sort of pleasure response, just like we humans do when we do something nice for others? To find out, the researchers decided to shake things up and see what happens when the celebration gets kicked up to another level and party drugs are thrown into the dance mix.
Robinson became interested in the waggle dance during a previous study investigating the role of octopamine in insect eating and movement behaviors. Octopamine is a biogenic amine (like histamine and serotonin) that’s found in higher levels in the brains of foraging honey bees than any other bees in the hive.
“The idea behind that study was that maybe this mechanism that structures selfish behavior – eating – was co-opted during social evolution to structure social behavior – that is, altruistic behavior,” Robinson said. “There are various lines of thought that indicate that one way of structuring society is to have altruistic behavior be pleasurable.”
Altruism is known to trigger a motivating pleasure response in the human brain, but the question remained whether the same reward mechanism existed in an insect’s brain.
So, in this new study Robinson and his research team at UI in Urbana-Champaign took things a step further. They found that when a foraging bee gets all hopped up on cocaine, it doesn’t matter how good the found food is or how much is stockpiled in the hive’s cupboards, bees just “Gotta Dance”.
Not only that, but the study’s results have also led the researchers to theorize that insects have motivating reward centers in their brains, just as humans do.
“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.
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.
A second set of experiments showed some interesting results. Non-foraging bees, it seems, were strict wallflowers: they never danced at all – no matter if they were on cocaine or not. And the coked-up foraging bees didn’t move about any more than non-foragers except when dancing, and when they did dance they only did so at appropriate times and only on the “dance floor”, no place else.
The honeybees, unfortunately, also seemed to suffer cocaine withdrawal symptoms, but the results of the study could lead to a better understanding of substance abuse in humans, and that’s fortunate for us.
The study was published in the Journal of Experimental Biology.
IUUC news release