Troubles in the Hive
After the Columbia Space Shuttle disaster, the Russians came to
our rescue by bringing down the astronauts who had served their
time on the International Space Station. Once again, “The
Russians are Combing”. That’s not a misprint, but the title of an
article by Gabriel Gluck in the August 19 issue of the New
Jersey newspaper The Star Ledger. The article detailed the
travails of Dianne, our town arboretum’s beekeeper. Last winter,
on a cold December day, Dianne went out to check her 50,000
charges in the box housing the hive. To her dismay, the door to
the box was open (a curious visitor?) and every last bee had
These were not your typical American honeybees. They were
Russian immigrants or their descendants. Dianne started out
with 5,000 bees and everything was going great, the population
soaring to the above-mentioned 50,000. Why the Russians?
They are good groomers and more hygienic in their habits than
the less fastidious American bees, which have been decimated by
a couple types of mites. It isn’t the loss of honey that’s the main
concern. It’s the some $15 billion dollars worth of produce in
this country that requires pollination by the bees.
The Russian bees not only groom themselves but each other,
brushing off and killing the mites in the process. They’re also
better housekeepers, cleaning the cells and tossing out those that
are infested with mites. By breeding American colonies with a
Russian queen, the local bees’ resistance to mites is doubled.
Speaking of breeding, it’s well known that bees have this tidy
arrangement wherein a lone female establishes herself as the one
and only queen bee. The other females are relegated to jobs as
workers. Her royal status entitles the queen to have the other
females fawn over her and provide her with food and protection.
The price she pays is having to single-handedly produce all those
eggs to perpetuate the hive. But, in New Zealand, this orderly
social structure has broken down and given way to anarchy.
In 1994, Ben Oldroyd, an associate professor at the University of
Sydney in Australia, and his colleagues published a paper about a
colony of bees in New Zealand in which workers were violating
the code and were producing their own offspring. I was tipped to
this anarchy by a brief item by K. M. Reese in the Newscripts
column of the August 18 issue of Chemical & Engineering News
(C&EN). The article discusses more recent studies of Oldroyd
and his colleagues, who are trying to determine whether there is
a genetic reason for this errant behavior. What they did was to
take some of these anarchists from New Zealand and propagate
their own colonies of anarchists in Australia.
To learn more, I visited the Web sites of the University of
Sydney and nature.com. I was provided with a whole new
perspective on life in the normal beehive. An article dated April
25, 2002 on the Nature site titled “The Police State” by John
Whitfield suggests that the hive is every bit as brutal as the
police states that we humans manage to come up with. Aside
from the infighting and maneuvering that the queen employs to
establish her royal status, maintaining order in the hive requires
the cooperation of the loyal female workers to quash any
deviations from the norm.
The New Zealanders are not the only bees that break the rules. A
few workers may deviate by laying their own eggs. When the
other workers realize what has happened they promptly eat the
deviant worker’s eggs. The queen maintains the devotion of her
subjects by emitting a pheromone, a substance that shuts down
the workers’ ovaries. In a hive of a few tens of thousands of
bees, only a handful ignore this pheromone signal and lay eggs
of their own. These eggs lack the royal scent, however, and the
workers devour them.
What happens to the eggs that don’t get eaten? Have you heard
of the term “haplodiploidy”? It seems that bees, wasps and ants
share this unusual means of determining the sex of offspring.
The anarchist worker bees that lay the eggs have not mated;
hence, the eggs are unfertilized. Yet they give birth to bees, all
of them male! The queen, who has mated, perhaps with more
than one suitor, produces fertilized eggs, all of which yield
females. The females are “diploid”, that is, they have two sets of
chromosomes, one set from the father and one from the royal
mother. The males from the worker eggs are “haploid”, that is,
they only have one set of chromosomes, from the worker mother.
This haploid-diploid business makes for some interesting
relationships. Since all the workers share the queen’s
chromosomes, they have a close relationship with her and with
each other. By tending to her needs and to her eggs they
encourage the propagation of their own genes. If the queen is
monogamous all the worker sisters also share the chromosomes
from the father and the sisterly bonds are especially close. When
one of the workers lays her own eggs, the resulting males are not
as closely related to the sisters and, lacking the sentimental
attachment to the future males, the sisters eat the eggs.
In those anarchistic colonies in New Zealand, it appears that a
substantial number of workers developed an insensitivity to the
queen’s pheromone. Not only were their ovaries active but they
also seem to have developed the capacity to camouflage their
own eggs to mimic the royal scent. Consequently, the other
workers tend to the eggs and a bunch of males are the result. An
alternate possibility is that the queen’s pheromone is weaker than
normal and doesn’t work as effectively in shutting down the
ovaries. In either case, the consequence for the hive can be
catastrophic. More and more unproductive males are produced
and the workers can’t keep up with the demand for food and care
and the hive degenerates into chaos.
In recent work, Oldroyd and colleagues have found a possible
genetic link to the anarchist bee phenomenon. Their idea is that
the queen’s pheromone somehow affects production of a protein
or proteins that switch off the ovaries. Perhaps a gene is highly
expressed. “Alien” is the name given to a gene that is known to
be associated with reproduction in other insects. This gene is
quite active (highly expressed) in queen bees that are not laying
eggs. The Australians found that Alien is highly expressed in
sterile worker bees but is lightly expressed in the anarchist egg-
laying workers. They speculate that the Alien gene could be a
key in keeping order in the normal honeybee colony.
We started off mentioning our problem with mites. South Africa
has another problem, the parasitic Cape honeybee. The Cape
bees are freeloaders and counterfeiters who come into a normal
honeybee hive and start laying their own diploid female eggs.
They counterfeit the royal scent and the hive’s original occupants
tend them as their own. The invaders do little work and produce
so rapidly that in a few months the hive is destroyed and the
Capes move into another unsuspecting hive.
Let’s all root for the “good” honeybees to evolve some sort of
effective defenses against these invaders and subverters. We
need those fruits and veggies! And if you’re in an arboretum,
please shut the door when you leave!
Allen F. Bortrum