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Honey bee chemoreceptors found for smell and taste
James
E. Kloeppel, Physical Sciences Editor
217-244-1073; kloeppel@uiuc.edu
10/25/2006
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CHAMPAIGN,
Ill. —
Honey bees have a much better sense of smell than fruit flies or mosquitoes,
but a much worse sense of taste, according to researchers at the University
of Illinois at Urbana-Champaign.
“The recently completed honey bee genome reveals a remarkable
expansion of the insect odorant receptor family compared with those
found in fruit flies or mosquitoes,” said Hugh M. Robertson,
a professor of entomology and an affiliate of the university’s Institute
for Genomic Biology. “The bee genome also reveals far fewer
gustatory receptors – those used for the sense of taste – than
we had anticipated.”
In work funded by the National Institutes of Health and reported in
the Oct. 26 issue of the journal Genome Research, Robertson and postdoctoral
research associate Kevin W. Wanner identified the family of honey bee
chemoreceptors that deals with smell and taste.
Honey bees (Apis mellifera) have 170 odorant receptors, the researchers
found, compared with 62 in fruit flies (Drosophila melanogaster) and
79 in mosquitoes (Anopheles gambiae).
The enhanced number of odorant receptors underlies the honey bee’s
remarkable olfactory abilities, including perception of pheromones,
kin recognition signals, and social communication within the hive.
Honey bees also use odor recognition for finding food. “Foraging
worker bees might encounter a bewildering number of flowers to choose
from, but they can discriminate between them using subtle olfactory
cues,” Robertson said. “A large number of odorant receptors
allows the bees to find food and communicate its location to other bees."
In striking contrast, the researchers found only 10 gustatory receptors
in A. mellifera, compared with 68 in D. melanogaster and 76 in A.
gambiae.
The low number of gustatory receptors for the sense of taste was unexpected,
Robertson said, but can be explained.
“Honey bees have a beneficial, non-antagonistic relationship with
plants, so plants don’t have to defend themselves with toxins,”
Robertson said.
“And in the nurturing environment of the hive,
bee larvae are provisioned by adults with food that is pretty much free
of toxins. Since the bees don’t have to detect toxins, they don’t
need many gustatory receptors.”
While honey bees don’t need many taste buds, they do require an
excellent sense of smell to detect chemical signals, such as pheromones,
that control bee behavior inside and outside the hive.
For example, the sole task of male drone bees is to mate with virgin
queen bees, and the male’s antennae are specifically designed
for the detection of queen pheromone.
“We have identified several honey bee odorant receptors that are
abundantly expressed in male antennae,” Robertson said. “This
moves us an important step closer to understanding the molecular details
of how bees, and insects in general, smell.”
Editor’s note: To reach Hugh Robertson, call 217-333-0489; e-mail: hughrobe@uiuc.edu.
