When a honey bee stings you, she makes the supreme sacrifice and dies.  She's usually defending her colony. In the process, she leaves behind part of her abdomen. A beekeeper simply scrapes the sting with a fingernail or a hive tool to stop the pulsating venom and continues working.

But is it ever possible for a bee to "unscrew the sting?"

A beginning beekeeper asked Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology, that very question last week.

She prefaced her question this way: "Richard Dawkins wrote in his biography that he observed a bee working her stinger out of his hand--unscrewing, so to speak--thereby not losing her stinger or her life.  Is this true?  I'm just a beginning beekeeper but have read many books on the subject and have never come across this interesting bit of information."

Mussen has been asked thousands of questions about bees since he joined the UC Davis faculty in 1976. Bee stings are just one of the topics. Like all beekeepers, he's been stung many times. It's no big deal.  However, one documented bee sting (below) turned out to be rather a big deal. It went viral. (It went from winning a feature photo contest sponsored by the Association for Communication Excellence (ACE),  an international association of communicators, educators and information technologists, to being named the Huffington Post's "Most Amazing Photos of 2012"; one of the Sacramento Bee's top 10 news stories of 2012; and My Science Academy's top photos of the year. Along the way,  scores of websites named it "Picture of the Day." It also will appear in a number of books.)

The photo (taken by yours truly) shows Mussen being stung by a bee in the apiary of the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, UC Davis. At the time, we were walking through the apiary when he noticed a bee loudly buzzing around him. "Get your camera ready, Kathy," he said. "The bee's going to sting me."

That's exactly what the bee did.  If you look closely, you can see the abdominal tissue, aka "guts," as she's trying to pull away. Usually a bee sting is a clean break.

So, can a bee "unscrew the sting?"

"As you may know, the sting of an adult worker honey bee has backward-pointing barbs that tend to hold the bee sting in the victim's flesh," Mussen told the beekeeper. "However, how well the sting stays stuck depends upon how deeply it was pushed in.  Yes, some bees seem to make only a half-hearted effort to sting.  The point of the sting pierces the skin, but doesn't go in very deeply.  At that point, the sting can be pulled out if the bee begins to leave.  It goes back up, inside the bee, but I do not know if, or how much, damage was done to the bee."

"These half-hearted stings are more commonly encountered with quite young workers.  Sometimes the sting remains, but no venom is felt.  Sometimes, a slight tinge of venom is momentarily noticed, then it is gone.  So, while most stings are the full-blown, driven-pretty-deep-into-the-flesh type, there are less assertive attempts that result in intermediate sting results.  The sting cannot be 'unscrewed,' because the barbs on the sting are directly across from each other and not in a spiral.  However, the barbs are larger as the sting penetrates deeper."