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Queen Bees "Brainwash" Workers With Chemicals

Anne Casselman
for National Geographic News
July 19, 2007
 
The queen honeybee would give Cinderella's wicked stepmother a run for her money.

A new study suggests the domineering matriarch regulates her daughters' brain activity to ensure her own survival.

"This is the first demonstration of [the queen's] pheromones acting directly on the brain," said study co-author Alison Mercer, a zoologist from the University of Otago in Dunedin, New Zealand. "The fact that it's affecting the learning abilities of the young bees is unexpected."

The Controlling Type

The queen bee produces a pheromone from a gland near her jaws. Pheromones are chemicals found in animals that trigger a behavioral response in another animal of that species.

One of the parts of the pheromone is homovanillyl alcohol (HVA). It interacts with a neurotransmitter called dopamine, which is found in the brains of insects and animals. In a mechanism that's still not understood, the pheromone may be able to block dopamine and prevent the young worker bees from avoiding negative stimuli. Worker bees—which surround and dote on the queen—are all female, and drone bees are male.

(Related: "No Reproductive Rights in Insect "Police States," Study Finds" [November 1, 2006].)

To test the theory, Mercer and colleagues exposed test bees to the pheromone. The team found these bees could not learn to associate specific smells with negative stimuli—in this case, mild electric shocks delivered by the researchers.

Mercer speculates that the queen bee herself might be a negative stimulus.

"It turns out the queen is completely blocking out the ability of the young bees to make an association between signals in their environment and any nasty outcome," Mercer said.

As these young worker bees age, however, the pheromone no longer has control over them—a mystery still being investigated by researchers.

The study appears in tomorrow's journal Science.

No Way Out

Studies have shown that bees avoid the queen's pheromones in high doses—too much and the worker bees become more aggressive. But the "brainwashing" pheromone may be keeping the workers from learning that being near their queen is unpleasant.

"If the young bees could build up an aversion to their own queen, they'd stop looking after her, and that would be to the detriment of the colony," Mercer said.

The pheromone could be the queen's insurance against the young workers rebelling, Mercer said. It's in the interests of both the colony and the queen that she has survival tools.

This begs the question of what effect the pheromone has on the queen herself, who is immobilized as a baby machine during her reign.

"It's important that she doesn't build up an aversion to any colony odors, otherwise she'd abscond from the hive," Mercer said.

The queen bee birthed all the workers, and all the workers are sisters, sharing half of their DNA. "Supersisters" share the same father and 75 percent of their DNA. (Related: "Bee Sex Gene Find Helps Solve 150-Year-Old Riddle" [September 8, 2003].)

Mark Winston, a biologist at Simon Fraser University in Vancouver, Canada, is unaffiliated with the study.

He's not sure that a dulled reaction to negative stimuli entirely explains why a young worker bee would stay close to her queen. Winston would like to see a future study take place inside the hive.

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