Promiscuous queen bees reign longer

November 14th, 2007 - 1:53 am ICT by admin  
That is what research by scientists in the Department of Entomology and W.M. Keck Center for Behavioral Biology at North Carolina State University suggests, found that the number of times a honey bee queen mates influences how attractive the queen is to the worker bees of a hive.

Researchers Richard, Tarpy, and Dr. Christina Grozinger found that the more partners, the more attractive the queen is and the longer her reign is likely to be.

The scientists also conducted experiments that suggest that the number of times a queen mates is a factor in altering the composition of a pheromone, or chemical signal, the queen produces. It is the composition of this pheromone that appears to attract the worker bees of a hive.

Since queens mate early in their lives and store semen, it stands to reason that queens that have mated multiple times and accumulate more semen might be more valuable to a colony.

To determine the effect mating has on honey bee queens, the scientists artificially inseminated queens.

They found that worker bees paid more attention to the multiply inseminated queens. Worker bees demonstrate what is known as a “retinue response” to their queen; they lick her and rub their antennae on her. The retinue response to the multiply inseminated queens was more pronounced.

“This tells us the workers can tell how many drones the queen has mated with,” said Grozinger.

Like many animals, honey bees use pheromones to communicate. When Richard analyzed pheromone produced in the mandibular gland of honey bee queens, she found that pheromone composition changes dramatically after queens mate and that the number of times the queen mates appears to be a key factor in determining the extent of pheromone alteration.

Tarpy added that when worker bees were exposed to pheromone from queens inseminated with semen from one drone and queens inseminated with semen from multiple drones, the workers showed a preference for the pheromone from the multiply inseminated queens.

Tarpy added that an analysis of the mandibular gland pheromone found differences in the chemical profile of pheromone from once-inseminated and multiply inseminated queens. The scientists also found differences in the two types of queens in brain-expression levels of a behaviourally relevant gene.

“Our results clearly demonstrate that insemination quantity alters queen physiology, queen pheromone profiles and queen-worker interactions,” the scientists write.

Tarpy said the research could have implications for bee breeding and for beekeepers. The research suggests that queens that mate with multiple partners are superior, so breeders may want to select for this behavior.

At the same time, beekeepers usually buy mated queens when they re-queen their hives. Tarpy said it should be possible to devise a test to determine if a queen has mated few or many times. Such a test would help beekeepers determine the quality of the queens they buy.

The research appears in the online scientific journal PLoS ONE. (ANI)

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