Bees use chemical password to show kinship.

Wouldn't life be simpler if, just by dabbing on the right cologne, you could guarantee that your colleagues would welcome you into a new office?

Such may be the case for honeybees introduced to a new hive.

Entomologists studying communication in bees have discovered that a newcomer's acceptance or rejection -- and possibly death -- appears to hinge on a single chemical signal that overrides a multitude of other odors emitted by bees or present in a hive. That chemical password may differ from hive to hive but seems consistent within a colony, says Michael D. Breed of the University of Colorado at Boulder.

Worker honeybees distinguish themselves in the animal kingdom by their extreme devotion to their colony. But this social system requires that they have some way to tell kin from unrelated interlopers.

For the past several years, Breed has investigated whether honeybees recognize their hivemates by a common "hive odor" that young bees learn and use as a cue for the rest of their lives. He separated various components of beeswax from the hive's honeycomb, then tested them to see which chemicals affected honeybee recognition. He could not isolate the exact compounds, but he did find that two chemicals -- hexadecane and methyl docosonoate -- were very similar to the ones in beeswax that honeybees seemed to depend on for communication.

Breed and Glennis E. Julian, then an undergraduate student from Pomona College in Claremont, Calif., went on to test the two chemical cues together and separately on bees removed from a single hive and raised in groups of 10. For five days, the researchers exposed each group to one, both or no chemicals. Then they placed a bee from one group with a different group and monitored the group's reaction to the newcomer.

"The most important finding is that the two chemicals are not equal in the way that they are being used," says Breed. In the June 25 NATURE, he and Julian report that bees treated with a single chemical bit and stung newcomers that happened to smell of the other chemical. This indicates that either chemical, presented by itself, could elicit acceptance or rejection.

Bees treated with both chemicals shunned newcomers wearing only the methyl docosonoate scent. But newcomers smelling only of hexadecane gained acceptance, even though group members were expecting the mixture. "If the bee had hexadecane, the bee would not be attacked," says Breed.

These results imply that bees seek to simplify their chemical conversations, Breed says. To make sense of the chemical chatter that exists in a hive, they follow innate rules that let them cue in on one password over other odors, he explains.

"For the first time, we're actually beginning to dissect the [honeybee's] decision-making process and the cue structure," comments Robert E. Page Jr., an entomologist at the University of California, Davis.

"But just looking at the structure of the compound, we cannot perceive what these rules are," Breed notes.

Even without knowing the rules, bee-keepers may be able to use the new findings. Often, apiarists must replace a queen. By treating the new queen and exposing the colony to the same chemical password, they could let bees in the hive know what to expect, making them more receptive to the queen, Breed suggests.