How Honeybees Smell

Scent means a lot to bees.   They use their sense of smell to check queen quality, sort out friend from foe, locate their hive or new hive after swarming, and find forage. Their sense is so acute that they can they can catch a scent while in flight.

Bees are able to detect scents with their mouths, antennae and tips of their legs (tarsi). In all these areas bees have sensilla: tiny, hair-shaped organs that incorporate receptor nerve cells.

They have 170 of these odor receptors in their antenna; double the number that mosquitoes have, according to a 2006 paper published in the journal Genome Research.

BEES SMELL FORAGE

When it comes to food, bees’ legs play the biggest role. Receptors in the tarsi and the tarsomeres allow bees to tsense both salt and sweetness, according to a study by Dr. Gabriela de Brito Sanchez, researcher, University of Toulouse, and Dr. Martin Giurfa, Director of the Research Center on Animal Cognition, in University of Toulouse, France.

Apparently sweetness is in the “claws” – at the tips of the legs

Salt sensors lie further up on the legs on the tarsomeres.

“The claw’s [the tip of the legs] sense of taste allows workers to detect nectar immediately when they land on flowers. Also, bees hovering over water ponds can promptly detect the presence of salts in water through the tarsomeres of their hanging legs,” writes Dr. Giurfa.

HUMAN IMPACT ON BEES SENSE OF SMELL

Bees’ sense of smell is a wondrous thing, but humans are again throwing more problems in the bees’ path.

DIESEL FUMES

Diesel fumes can mess with bees’ odor detectors.

English scientists published a study in Scientific Reports  which demonstrated that elements of diesel fumes, nitric oxide and nitrogen dioxide, are masking the scent of flowers. Tracey Newman, a neuroscientist at the University of Southampton. “The [effect of diesel fumes on flower scent] could have serious detrimental effects on the number of honeybee colonies and pollination activity.”

NEONICOTINOIDS & COUMAPHOS

Researchers Sally Williamson and Geraldine Wright showed in a 2013 study that these much  used and now notorious chemicals lessen the ability of honeybees to distinguish odors and to learn new scents.  This, in turn, adds to the memory loss in honeybees associated with these substances.

BEES WORK FOR HUMANS

We humans may well be messing with the bees ability to smell, but we also depend on their ability to detect odors, and not just for pollination and honey. Like other animals, bees can be trained to relate a smell to a food rewards

BEES SNIFF OUT BOMBS

The Stealthy Insect Sensor Project at the Los Alamos National Laboratory has trained bees to detect bombs. Researchers trained bees to link the smell of sugar syrup to the smell of bomb ingredients. When a bee detected sugar or explosives, she extended her “tongue” (proboscis)

BEES SCENT DISEASE

Cancer patients may soon breath into a glass ball with bees in it.

A Portuguese designer, Susana Soares, created a glass dome with two chambers. A small area is the “diagnostic space”; the larger area is where bees are placed during the test. “People exhale into the smaller chamber, and the bees rush into it if they detect on the breath the odor that they were trained to target,” writes Soares.

The bees train quickly, according to Soares. In ten minutes her bees area able to detect forms of early stage cancer, tuberculosis and diabetes.

BEES SMELL NICE

I cannot write a post on “how do bees smell” without caving into the obvious. I just have to say it: honeybees smell nice. The odor of a healthy hive in summer is a wondrous thing. To me the scent brings thoughts of blue skies, light clouds, cedar branches bending on ridges above slopes of flowers – and honey and a healthy hive. That’s how bees smell.

That’s the news from Brookfield Farm Bees And Honey in Maple Falls, Washington. A side note is that I’ll be giving a talk on Honeybees at the Mt. Vernon, WA, library on November 20 at 6pm. It’s the basics: from bee reproduction to the hazards bees face to honey.