Hi All,

I want to add an argument I had already brought up on several other sites on
the Internet, that would make the DL hypothesis even far less attractive
than any of its staunch supporters believe it to be. DL INFORMATION DOES NOT
INDICATE THE SITE VISITED BY THE DANCERS, NOR EVEN THE VICINITY OF THAT
SITE.

We know that direction-information for any specific site has a normal
distribution.  This means that the majority of dance-attendants would be
subject to incorrect direction-information. Even a small deviation from the
correct direction translates to a considerably large distance from the
correct site, when the site is far from the hive. Moreover, to uphold his DL
hypothesis, v. Frisch was obliged to introduce (as one of his very many
auxiliary hypotheses), the claim that recruits contribute errors of their
own, to the errors contained in foragers'-dances, to the extent that the
combined errors can even send some recruits in exactly the opposite
direction to that of the foragers'-feeder.

Distance-information contained in dances suffers from the same type of
problems. But, it also suffers from another major problem. V. Frisch
concluded that distance-information in dances is determined by the
expenditure of energy; which makes sense. The foragers are more exhausted,
and, therefore, dance more slowly after flying to a more distant feeder and
back. He concluded, however, on the basis of various tests done by himself,
and by others, that, more specifically, distance-information in dances is
determined by the amount of energy spent on flight to the feeder and back,
with the amount spent on returning to the hive given a smaller weight. Never
mind that this requires the foragers to separately measure the amount of
energy spent on the flight to the feeder, and back, then multiply the amount
spent on returning to the hive by the weighing factor (which must be smaller
than one), and add the result to the amount spent on the flight to the
feeder. There is no evidence that honeybees can do any of that.

Besides, if they could separately measure the amount of energy spent on the
flight back to the hive, why take it into account at all, as v. Frisch
claimed that the foragers did? Recruits need to know the distance to fly in
terms of the amount of energy needed to fly unloaded, from the hive to the
food. When the foragers fly back to the hive, they fly loaded, and in stable
wind conditions, they also fly in exactly the reverse direction in relation
to the direction of the wind when they flew to the feeder (except in the
rare case of a crosswind flight). In other words, the amount of energy spent
on returning to the hive would only mislead recruits. Well, at least giving
that amount a smaller weight, ameliorates the problem to some extent. Why do
the foragers not exclude an effect of this misleading amount of energy,
after measuring it separately? V. Frisch would claim that the bees do it all
'instinctively", and evolution has simply not made it possible for them to
ignore the effect of the misleading amount of energy, but it endowed the
bees with an ability to give that amount a smaller weight. You don't argue
with anything that evolution can presumably achieve through "instincts"
(unless, like me, and many others, you don't believe in the existence of
"instincts" in the first place).

Lindauer, with his penchant for "inventions", however, "solved" the problem
of the misleading amount of energy by simply stating (without the slightest
evidence), that under natural conditions distance-indication depends only on
the amount of energy spent on the flight from the hive to the food. See:

Lindauer, Martin (1976). Foraging and Homing Flight of the Honey-Bee: Some
General Problems of Orientation PP. 199-216 in *Insect Flight *. R. C.
Rainey, ed. Halsted Press, UK.

Many of you must have heard of the more recent "solution" to the problem, in
a form which exclude the effects of the expenditure of energy altogether,
and claims, instead,  that honeybee-foragers  have an "odometer", that
enables them to measure distance-flown by the total amount of angular
deviations of "background images". I.e., distance-indication in dances
depends on what the foragers see along the way. (What about the effect of
the expenditure of energy? It appears to have somehow disappeared. Where did
it go, though?) Interestingly, the possibility that optic-stimuli might
affect distance-indication in dances was already raised by Lindauer , in
the publication noted above, where, very interestingly, he also notes
unpublished findings by Meese, that visual properties of the environment in
which the foragers fly, have no effect whatsoever on the distance-indication
in their dances. If Meese had only published his findings! Had he done that
we would have been spared all the egregious nonsense about the honeybee
"odometer".

So, we have no choice but to return to the issue of the expenditure of
energy on distance-indication in foragers'-dances. Contrary to v. Frisch,
Khalifman, however, claimed in Pchelovodstvo of 1950 (without bothering to
provide any information about tests and results), that distance-indication
depends only on the flight from the food back to the hive). This, naturally,
spells disaster for the DL hypothesis, and was (therefore), completely
ignored by DL supporters, except (as far as I know), for Butler, who noted
Khalifman's claim in  his 1962 book: "The World of the Honeybee", and
dismissed it with his pronouncement that Khalifman must have erred.

Basic physiological considerations, however, lead to the conclusion that ,
under the most common experimental conditions (feeder not inordinately far
from the hive, filled with enough sugar-water for many foragers to
repeatedly fill their honey-sacs there), Khalifman's claim must be correct .
Why? Because when they feed at the feeder the foragers rest, and also
"refuel". All the after-effects of the flight from the hive to the food, in
terms of physiological exhaustion, and expenditure of energy, must,
therefore, completely disappear by the time the foragers prepare to fly back
to the hive!

Incidentally, Bizetzky, a colleague of v. Frisch discovered that foragers
indicate a far greater distance than actually traversed, when forced to
crawl, instead of fly to the food & back. It is now obvious to me that this
involves a very different situation, because when the foragers crawl, apart
from a general physiological exhaustion resulting from this activity, there
is also a specific physiological exhaustion of the leg-muscles, the main
organs used in dancing. There is also an additional effect of the difficulty
of getting rid of excess body-heat produced by physical activity, when the
bee moves relatively slowly through the air, i.e. when it crawls instead of
flying.   V. Frisch, however, claimed (in his 1967 book), that crawling
requires of honeybees far more energy than flying; which I found incredible
the first time I encountered it. I now wish I had stopped right there and
then to do what I did only years later, i.e. consider that during the
foraging season honeybees spend most of their lives crawling inside the
hive, before they even become "field bees", and even active foragers spend a
considerable amount of time crawling, and not flying. Flight certainly saves
time, but it does not at all save energy.

Back to Khalifman. His conclusion receives further support from a report by
Gould & Gould, in their 1988 book "The Honey Bee", that among bees
transported to a feeder in an area where they had apparently never foraged
before, there were individuals who found their way back to the hive, and
then indicated the feeder in their dances. In other words, the fact that
they never spent any energy on flying to the feeder, since they were simply
transported to the site,
had no effect on their dances.

The reason I spend so much time on this issue is that the belief that
honeybee dances contain spatial information about the approximate location
of the site visited by the foragers, has played a major role in leading many
to accept that honeybees have a DL. After all, scientists could obtain that
spatial information from foragers'-dances. Never mind that scientists could
do it only on the basis of a detailed preliminary research on the relation
between various aspects of the dance and the distance & direction of the
foragers'-feeder, that had to be done separately for each honeybee species &
strain. Many were especially impressed by v. Frisch's own report (see his
1967 book), that he made his assistants train marked foragers to a feeder
they hid in the grass, without telling him where it was, and he was then
able to find the feeder by studying the dances of those foragers in the
hive. Wenner pointed out in print,  however (and I can not give you the
exact reference, which I do not remember), that v. Frisch was able to do it
only after studying many different dances. But for overly naive scientists,
and laymen, the very fact that the dances contained information that enabled
scientists to find the foragers'-feeder, raised the issue of what the dances
could be good for except to provide nest-mate with that kind of information,
and, then, to the conclusion that this is what the dances actually do.

Khlifman's probably quite correct conclusion, however, means that the dances
contain misleading information about the approximate location of the site
visited by the dancing foragers. You might think that the problem is
nonetheless, not terribly serious, because if you could only ignore the
effect of the wind, foragers can carry only a limited amount of food in
their honey-sacs, and different individuals may carry a similar amount of
food,  which does not weigh very much anyway. So the spatial information
contained in the dances can not be too misleading anyway., Well, it is bound
to be terribly misleading when the foragers carry both pollen & nectar, or
only pollen, because as Ribbands concluded on the basis of his own studies,
and reported in his 1953 book, "The Behaviour and Social Life of Honeybees",
the weight of the pollen pollen gatherers carry varies with the amount, and
the type of pollen, and can amount almost to a foragers' own body weight.
This can easily turn distance information contained in foragers'-dances, can
easily make distance-information contained in dances, quite useless. What
good is distance-information that is determined by the amount of energy
spent on the flight from the food back to the hive,  when the forager is
flying in exactly the opposite direction in relation to the wind, than
recruits need to fly, and carries a load that can equal almost its own body
weight, when recruits need to fly unloaded? All the information scientists
have gathered about foragers'-dances applies only to foragers collecting
sugar-water, or anything else that does not weigh much more, and is carried
inside the honey-sac. The information is useless, when the dancers carry
other types of load. Moreover, evolution could not equip dance-attendants
with the ability to obtain useful information from the dances of
pollen-gatherers, when dance-attendants have no way of even knowing the
weight of the load the foragers brought in.

Can anyone still seriously consider the possibility that honeybees may have
a DL that informs recruits approximately where to go?

I do not even want to begin to consider the far more complex situation that
obtains in nature, where foragers need to gather food from many different
flowers during each foraging trips, with only brief rests on each flower,
and where (according to Ribbands), the foragers can easily fly far longer
distances when moving from one flower to another, than they they cover in
flying to the foraging area & back, and when different individuals fly very
different routes when actually gathering the food. (Ribbands found in tests
done in an orchard, that some foragers gather food from flowers on one and
the same tree, but others-don't do that at all.)


Sincerely,
Ruth Rosin ("Prickly pear")

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