Honeybee Navigation Explained: They Cheat =========================================
Abstract ========Honeybees are remarkably skilled navigators. Once they discover a food source, they can return to it time and time again with extraordinary precision. Many researchers worldwide have dedicated their lives to unraveling the mechanism of this ability. Their experiments are a model of ingenuity, admirable both for attention to detail and their use of careful controls.
It is with profound regret, therefore, that we present evidence of a previously unsuspected factor at work in honeybee navigation which renders all experimental work to date untrustworthy and of dubious value. Specifically, we will show that within every hive there is a "radio beacon" acting as a reference point for foraging bees. We question the widespread belief that many subtle environmental cues influence honeybee navigation, since these "influences" may simply be the result of inadvertent disturbances of the beacon signal caused unwittingly by the experimenters themselves.
Since Aristotle, the precision with which honeybees and other social
insects can return to previously visited locations has intrigued and
baffled investigators. Most now believe that this remarkable ability
is possible only because bees are sensitive to an entire hierarchy of
distinct factors, including the polarization of sunlight, the magnetic
field of the Earth, odor cues, arrangements of physical landmarks,
To us, this list of factors looked suspiciously long. It seemed that almost any feature anyone cared to test turned out to indeed have an effect on honeybee navigation. But did this truly reflect reality, or could it possibly be an artifact of the experimental methodology in use? We performed a series of trials to investigate this. These tested the effect on bees of capriciously selected features, such as prices on the New York Stock Exchange. Despite our suspicions, we were stunned to discover that there was a statistically significant effect on bee activity in each case! Clearly honeybees were either more financially active than hitherto suspected, or we were failing to control some aspect of the experiment. This paper presents the trail of evidence that led to our startling conclusion: that honeybees make use of an elegantly simple radio transmitter in their hive as a reference beacon for navigation.
The Initial Experiments
Our first experiments tried to determine the effect of the following
factors on honeybee navigation :-
We placed a hive populated by a honeybee colony (Apis mellifera) in a large empty room. The floor, ceiling, and walls were painted a uniform gray, and illuminated uniformly by indirect artificial light. We positioned a single food source approximately 10 meters from the hive. A hidden observer beneath the hive recorded the activity of the bees against the current state of the factor being tested.
Clearly we were expecting to find no significant correlation between the factors listed above and the activity of the bees. In fact, however, there was a marked effect. The crucial clue was that the bees were affected when there was a transition in the factor, rather than while it was in any particular state. This immediately focused our suspicion on the hidden observer, who himself received updates of the state of the factor only when it changed. The conclusion was obvious and unavoidable. The radio communications between the observer and the base must affect the activity of the bees. Direct tests revealed that this was in fact the case.
With this simple discovery, everything fell into place. If honeybees
are sensitive to radio, then any electrical device can potentially
contaminate experiments. Hand radios are in widespread use for
communication between observers in animal behavior studies. All it
takes is for the pattern of communication to be correlated with the
features being tested, and the behavior of the bees will also show a
correlation with those features. Experiments on sensitivity to
magnetic fields are particularly questionable now, given their
reliance on the use of strong electromagnets in the immediate vicinity
of the hive.
Follow-on experiments showed that the bees were sensitive not to
continuous radio broadcasts, but to transient effects when a signal
began or ended abruptly. We were curious as to why this might be. We
had acquired a Faraday cage for use in the telepathy experiment, and
this proved useful now. Since a Faraday cage blocks all radio signals
from entering or leaving the area within it, it was ideal for our
purposes. First, we tried capturing some of the honeybees and placing
them within the cage. This did indeed seem to disorient them and
prevent them from reaching the food source or returning to the hive.
Unfortunately this was not entirely convincing since the mesh of the
cage was too fine for the bees to escape through anyway. Placing the
cage around the hive gave more conclusive results. Bees outside the
hive became entirely disoriented, and flew around apparently at
random. This suggested, bizarre as it seemed, that there was a radio
source within the hive. But how could this be possible? Surely
someone would have noticed something like a bee D.J. hosting a chat
show in the hive! It was clear that the radio source must be
essentially invisible to a human observer.
To find the source, we proceeded as follows. The easiest way to generate radio waves is to use electricity. If the bees were using electricity, there had to be a current flowing from the hive to the ground. To test this, we suspended the hive from the ceiling via a single wire, and then ran that wire to the earth through an ammeter. There was indeed a small, discontinuous, spiky current flowing. We then decided to divide the hive in half repeatedly, and test each half, until we homed in on the radio source. Unfortunately, when we divided the hive in half, and tested each half, *both* were generating a current. This was true no matter how finely we divided the hive, with the current getting smaller and smaller in proportion with the size of the hive segment remaining. Finally we ended up with a small piece of honey comb with a single bee on it, generating a miniscule current every now and then. It was only then that we were able to lay aside our preconceived notions shaped by human technology and understand what must be happening before our eyes. The bee was simply rubbing the fur of its legs together, building up a static charge, and discharging against the comb! The tiny spark generated was undetectable to the human eye, but would result in a very small radio pulse or "click". An entire hive doing this would make an excellent homing signal and reference beacon for foraging bees- as long as no interfering humans were around to pollute the airwaves.
Once again, we see nature coming up with an elegantly simple solution
to a complex problem - a solution so elegant and so simple that it has
in fact proven entirely invisible to human observers down through the
centuries. At a pragmatic level, it teaches us as researchers that we
can never fully control for the unexpected. At a more philosophical
level, it warns us of how easily we can interfere with nature's
delicate mechanisms without even realizing they exist. Clearly the
only honorable path to take in this case, now we know that our
technology interferes with insect navigation, is to abandon science
and retreat to our primeval hunter/gatherer state. Do we have the
integrity to do it?
As a first step, perhaps you might consider giving a donation to the "Save the Social Hymenoptera" fund today, and help make the world of tomorrow a safer place for all our larvae.