There are very many claims of experimental evidence for the existence
of the honeybee DL, published in refereed scientific journals,
including the most prestigious such journals, like Nature & Science
..Most of these claims, by far, are based on distributions of
new-arrivals, and as I explained in an earlier post, all claims based
on such data are doubly non-valid, because the authors invariably rely
on erroneous expectations from both possibilities. I noted, however,
that carefully analyzing the faults that can be found in such
individual claims, can be very interesting & instructive.
I shall provide here only a partial analysis of only 2 such claims
that are of special interest, i.e. the claims based on the studies by
James, L. Gould (in Nature of 1974; Science of 1975; J. comp. Physiol.
of 1975), and the claims based on the use of a dancing "robot" bee [by
Michelsen et al. (in Naturwiss. of 1989), and by Kirchner & Towne (in
Scientific American of 1994)]. Why are these specific claims of
particular interest? Because Gould's claims have been touted
practically everywhere, including in the general college textbook
Biological Science (1996, 6th revised edition), by Gould & Keeton,
apparently used by millions of students all over the world. The claims
by Gould, and by the "robot" bee team, are included in a Foreword by
Thomas Seeley, a staunch DL sup****ter, to a 1993 reprint by Harvard
University Press, of v. Frisch's definitive book on the honeybee DL:
The Dance Language and Orientation of Bees (1967; translated from the
original German publication of 1965). (Seeley's Introduction is
supposed to show that the DL controversy had been closed in favor of DL
sup****ters.) The claims by Gould are enlisted, as further sup****t by
Riley et al., who published (in Nature of 2005), the latest claim (that
I had already dealt with in an earlier post), that their radar-tracking
study of the flights of honeybee-recruits experimentally confirms the
existence of the honeybee DL.
All those 2 types of claims are based on distributions of new-arrivals,
and I had already explained that all claims of this type are doubly
non-valid. Here, however, I want to delve into details underlying those
claims, just to demonstrate the extent to which staunch DL sup****ters
have been able to delude themselves, and practically everyone else,
except staunch DL opponents.
Gould used distance-arrays, or direction-arrays, of stations, with a
foragers'-station invariably on one side of the array, relatively far
from the array, and with foragers that (by use of a special "trick"),
were made to provide "misdirected" information, which indicated another
station than their own. In the tests, these foragers were made to
invariably indicate one station or another (a DL station), in the
array. Tests were done under v. Frisch's conditions, and Wenner's
conditions. (The differences concern only preparations for actual tests
on honeybee-recruitment.) Interestingly, Gould was encouraged to carry
out those studies by his major PhD adviser, Donald Griffin; the first
enthusiastic sup****ter of the DL hypothesis in the US, who is by now
"gone to a better world".
In Gould's published results under v. Frisch's conditions the
distributions of new-arrivals were normal (as long as you excluded
new-arrivals at the foragers'-station itself), with a maximum at the DL
station, even when Gould repeatedly assigned the role of DL station to
another array-station. In short, the results (minus new-arrivals at the
foragers'-station) fit the (erroneous) expectations of DL sup****ters
from the DL hypothesis. The distributions of new-arrivals in the tests
under v. Wenner's conditions, grossly contradicted those expectations
from the DL hypothesis. But they also grossly contradicted Gould's own
expectations from use of odor alone all along (which he did not
notice).
Gould's results under v. Frisch's conditions pose a problem even for
the (erroneous) expectations of DL sup****ters themselves, from the DL
hypothesis, and the problem is especially prominent in the
direction-tests (re****ted in the 1975 Science publication). Contrary to
those expectations, the distributions of new-arrivals are strongly
skewed towards the side of the foragers'-station, or even quite
abnormal (with more new-arrivals at the foragers'-station than at an
array-station that is much closer to the DL station). Those
new-arrivals at the foragers'-station were not even mentioned in
Gould's first, brief re****t on his studies (in Nature of 1974). All
attempts by Gould, and by other DL sup****ters, to exclude those
new-arrivals ( and those new-arrivals alone), from the distributions of
new-arrivals under v. Frisch's conditions, in order to make the results
better fit the (erroneous) expectations from the DL hypothesis, have
turned out to be "a remedy worse than the disease".
I explained in an earlier post, that Gould's expectations from use of
odor alone all along were based on his own "specific natural
locale-odors" hypothesis, which is totally irrelevant to the whole DL
controversy; which, in turn, means that his interpretations of his
distributions of new-arrivals are also totally irrelevant to the whole
controversy.
In fact, there are very many factors that are expected to affect
results due to use of odor alone all along, and the effects are not
simply additive, but synergistic. And Gould's experimental design
involved such a complex situation from the point of view of use of odor
alone all along, that we can have a general idea of the various
factors expected to affect use of odor alone all along, but no one can
actually determine the expectations from such use in Gould's
experiments. His results, therefore, actually sup****t the "odor alone
all along" hypothesis vs. the DL hypothesis, not at all because they
show a better fit with the un-determinable expectations from use of
odor alone all along, but for a very different reason. The reason is
that Gould had failed to provide the essential experimental
confirmation for the DL hypothesis; which leaves only the other
alternative, i.e. use of odor alone all along. There is no third
alternative.
His results also sup****t the "odor alone all along" vs. the DL
hypothesis, for another, very different reason. In his direction-tests
(re****ted in Science of 1975), he provided the number of dances
performed during each period of tallying new-arrivals. He did not need
these data, and he never used them, but, fortunately for DL opponents,
he gathered the data, and also took the trouble to publish them. And
this enabled me to use the data. Some very simple calculations lead to
the conclusion that new-arrivals under Wenners'-conditions (mostly
users of odor alone all along, according to Gould), were even much more
efficient than new-arrivals under v. Frisch's conditions (mostly users
of DL information, according to Gould), in terms of the average number
of dances performed per new-arrival. (Only one tallying period under v.
Frisch's conditions, constitutes an exception to this rule, and it is
the tallying period which should be accorded the least weight, because
it had an unusually small total sample of new-arrivals.) I published
that in my first critique of Gould's claim (in J. theoret. Biol. in
1978.)
Flying insects in general, including solitary insects, can find sources
f attractive odors in the field by use of odor alone all along. This
means that honeybees must have been able to do the same thing, since
long before they evolved into social bees, or into any kind of bees. A
honeybee DL, whose use is less efficient than use of odor alone all
along, could, therefore, never evolve in the first place; i.e. even if
it could evolve in a single individual, it could never spread to the
whole species, or even to a single population.
As noted above, Gould's expectations from use of odor alone all along,
are based on his own, "specific natural locale-odors" hypothesis (which
he actually attributed to Wenner, even though the first study on
honeybee-recruitment published by Wenner's team in 1967, already
grossly contradicts the expectations from such a hypothesis; which
Gould did not notice). According to that hypothesis, when recruits use
odor alone all along, they still use information about the approximate
site of the foragers'-station. They obtain this information, however,
not from dances, but by using the specific natural-odors (that the
foragers carry into the hive from the locale of the foragers'-station),
to identify that locale on a map of the "olfactory landscape" over the
whole foraging area of the colony. They then fly to that locale, and
search there. Those who miss the foragers-station, then, gradually
extend their search further from that locale, thus finding other
stations. The expectations from such use of odor alone all along are,
therefore, normal distributions of new-arrivals, with a maximum at the
foragers'-station. I.e., the expectations are practically the same as
the expectations of DL sup****ters themselves, from the DL hypothesis;
as long as the foragers indicate their own station, i.e. as long as the
foragers'-station is identical with the DL station; which is normally
the case. This was the rationale that gave Gould the idea to separate
the foragers'-station from the DL station, by making the foragers
provide "misdirected" information.
Let us, however, take a better look at the "specific natural
locale-odors" hypothesis. When Gould first introduced that hypothesis
he noted the difference in specific locale-odors between relatively
very large areas, such as a woods, and an open field. He also claimed
that this hypothesis makes it possible to explain all of v. Frisch's
results by use of odor alone all along. V. Frisch, however, often
introduced into his experiments (for reasons that I shall skip), two
stations, one on each side of his foragers'-station, and only 50 m.
away from that station. To explain the results obtained by v. Frisch
in such experiments by use of odor alone all along (on the basis of the
"specific locale etc." hypothesis), the map of the "olfactory
landscape" would, therefore, have to have a far higher
resolution-power, sufficient to distinguish between two sites that are
only 50 m. apart.
This means that field-bees would have to divide the whole foraging area
by a grid of small squares (each with a 50 m. side), then (with their
exceptionally high sensitivity to odors), gather, for each square, the
information about all the natural odors they can sense within that
square. Odors from sources outside that square cannot be used to
identify that square, because they might very well not be sensed within
the square, once the wind changes direction. The bees must, therefore,
exclude from the list all odors sensed inside the square, whose sources
are outside the square. This means that once they sense a specific odor
they must zigzag upwind until they find the source, or verify that the
source is outside the square.
Now, v. Frisch's foragers still danced for a distance of 8.5 km. from
the hive. In all my calculations I shall, however, deliberately play
the devils advocate, in favor of DL sup****ters. I shall, therefore, use
the conservative value of only 8 km. The number of small squares within
an area of an 8 km. radius is [ 3.14x8,000x8,000): (50X50)], which is
over 80,000 squares. (You begin to get the idea!) Assuming very
conservatively that the bees can gather all the required information
from a single square in only 1 min., and that they fly non-stop
(without rest, or "refueling"), for 20 hrs. per day (even though
honeybees fly only during daylight time), they would need
[80,000:(60x20)], which comes to over 65 days, just to obtain the
information needed to construct a single map of the "olfactory
landscape". The bees would also need to know (for use when they are
being recruited), how to reach each square through a direct flight from
the hive, and do everything "in their heads", without laying any actual
grid on the ground, and without pencil & paper.
During the foraging season field-bees work so hard that they do not
live for more than 2-3 weeks. I.e. they do not live long enough to
gather the information needed to construct even a single map. On top of
all that, environmental odors keep continually changing, as flowers
bloom, open, close, wither, as animals trample and chew on vegetation,
and leave behind their excretions, and secretions, as fallen leaves
deteriorate under the effect of the sun, or of bacteria, etc. This
requires that a map that takes at least 65 days to construct, be
reconstructed many times over, every day.
Even if field bees had sufficient time to construct, and continually
update their maps, the maps would actually be useless, because a
forager foraging at a specific source inside a specific square, could
not carry any odors from sources that are within that square, but
upwind of the specific source. So, how is a recruit going to use its
map to identify the square the forager came from? Apart from that,
gathering the information required for constructing the map, actually
requires the bees to find the sources of practically all odors they can
sense over the whole foraging area. They would, of course, be much
better off stopping to feed at the first flowers with rich food, they
find while trying to gather the information for the map, and simply
forget about the map altogether.
In Quart. Rev. Biol., Gould (1976) already reviewed the whole DL
controversy in retrospect, as a closed case, with his claim to have
conclusively experimentally confirmed the existence of the honeybee DL.
And, incredibly, his claim is still being touted by staunch DL
sup****ters 30 years later.
In the study with the dancing "robot" bee (that never left the hive),
by Michelsen et al. (whose team included Martin Lindauer, v. Frisch's
best known former student and collaborator), the results of all the
distance-tests grossly contradicted the expectations of DL sup****ters
themselves, from the DL hypothesis. (The maximum of new-arrivals never
occurred at the DL station.) The Authors suggested that some tall trees
that were not anywhere near any flight-routes of recruits (expected
according to the DL hypothesis), might have distorted the results. (If
such a pretext could be seriously considered, almost all studies on
honeybee-recruitment would have to be dumped in the waste-basket,
because there usually were some tall trees, nearby, or far away.)
Most of the direction-tests (tests with all stations at the same
distance from the hive), the spatial design was heavily biased in favor
of the DL hypothesis. The experimenters used a DL station, and an
"opposite" station, with the wind blowing perpendicularly to the
directions of those stations, and with the addition of 2 other
stations, one on each side of the DL station, 45 degrees away from it.
Under such conditions use of odor alone all along is expected to result
in a maximum at the DL station, and a minimum at the "opposite" station
(due to an effect of the "spatial design", that I shall not explain
here.) These are exactly the type of results the authors obtained. The
authors claim that the results (which fit their expectations from the
DL hypothesis, and contradict their expectations from use of odor alone
all along), confirm the DL hypothesis. Their expectations from both
possibilities are, of course, in error.
The authors also provide the results of only 2 direction-tests, with
only a DL station, and an "opposite", in a cross-wind, i.e. without any
bias in the "spatial design". This time the DL station still received
more new-arrivals than the 'opposite" station. A wind that blows in one
perfectly fixed direction, however, does not exist in nature. And any
accidental slight change in wind direction that would result in the DL
station being closer to the upwind direction than the "opposite"
station, would confer an advantage to the DL station, by use of odor
alone all along; especially if such a change occurred during a later
part of the test (due to an effect of the "tem****al design", which I
shall not explain here, either). However, even without an effect of the
"tem****al design", stations that are upwind of the hive have an
advantage from the point of view of use of odor alone all along.). With
only 2 such test, the probability that a maximum at the DL station
would occur by accident is 25%; which means that the results can in no
way be considered as significant.
Another study on honeybee-recruitment using the "robot" bee, was done
by Kirchner & Towne (1994), who carried out only direction-tests, with
8, equally stations arranged in a circle around the hive, and provided
results for only 2 such tests. The results show normal distributions
with a maximum of new-arrivals at the DL station. But the authors
provide no information whatsoever about wind-direction, the most
im****tant factor for use of odor alone all along in tests with this
specific "spatial design. Interestingly, Kirchner was a member of the
team of Michelsen et al., noted above, and Towne was a former student f
Gould. Also, note that the authors did not carry out any distance
tests. Why "tempt the devil"?
One additional point deserves mention:
>From a certain stage on v. Frisch introduced the use of stations
without food, except, of course, the foragers'-station which had to
have food. This made it unnecessary to capture new-arrivals at the
food-less station, because there was no possibility that they would
become regular foragers there and indicate those stations in their
dances. Moreover, new-arrivals often approached such stations, without
actually landing. V. Frisch, therefore, stopped capturing new-arrivals
at such stations, and began to use the criterion of the typical manner
of arrival, to count new-arrivals at such stations, and , thus,
distinguish them from bees accidentally flying by. In other words, he
counted as new-arrivals at such stations only bees that approached
through an upwind zigzag, from outside the visual field of observers at
the station, to within 20 cm. of the station.
I stressed, in an earlier post, that this typical manner of arrival
alone suffices to completely discredit the whole DL hypothesis. (This
point had actually been briefly raised by Wenner in print, in 1974). V.
Frisch, as well as anyone else who used that criterion, were, thus,
continually looking at evidence which suffices to completely discredit
the DL hypothesis. But they never "saw" it, because they were intent
only on obtaining a confirmation for the existence of that DL, based on
where new-arrivals arrived. All DL sup****ters who experimented with the
"robot" bee used v. Frisch's criterion for identifying new-arrivals. In
Gould's studies new-arrivals at array-stations were captured
automatically, but new-arrivals at the foragers'-station had to be
captured, and removed, by hand. Which means that the typical manner of
arrival could have been easily observed also in his studies. And he, in
fact, mentions the typical, invariable manner of arrival, in print.
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