>What is the current consensus on the "waggle dance" controversy? I thought
>that the robot bee work reported in National Geographic a few years ago had
>proved Von Frisch correct but I came across a recent book by Wenner and
>Wells still arguing in favour of the odour hypothesis.
No, from our perspective, the "robot bee" did not settle the issue, as
reviewed in one of our papers (1991 Wenner, A.M., D. Meade, and L. J.
Friesen. Recruitment, search behavior, and flight ranges of honey bees.
American Zoologist. 31(6):768-782).
Those who would focus on experiments with odor transport downwind from
food sources and hive placement have a strong future for obtaining
rewarding results. Next month I will be presenting the following abstract
at the AMERICAN BEE RESEARCH CONFERENCE in Georgia (one that will be
published in the December issue of the AMERICAN BEE JOURNAL):
--DRAFT--
*********
A recent claim (Webster & Caron, Bee Culture 123:403-406): "The evidence
for dance language is strong," ignored 13 salient points published 21 years
earlier in the same publication (Wells & Wenner, Gleanings in Bee Culture
102:110-111,127). I update and expand upon those points here.
The dance maneuver information is not sufficiently accurate to account
for supportive experimental results obtained by language proponents;
rather, the experimental designs used apparently funnel recruits into
"intended" sites. Von Frisch recognized in 1937 (Wenner, with von Frisch,
Bee World 74:90-98) - that one gets no recruits with no odor. However, von
Frisch (and others at the time) failed to perceive that his 1940s
experiments lacked necessary controls against odor influencing results;
later, his results did not survive tests in double-controlled and strong
inference experiments. Only by using odor in single controlled experiments
can one obtain supportive results; thus, one can no longer justifiably
explain "positive" results with an uncritical assumption of "language."
Recruit search behavior is remarkably inefficient. Most recruits
require several flights out from the hive before locating the target food
source, are in the air many times longer than necessary for a direct
flight, and succeed only rarely unless one provides sufficient odor at the
site. One can easily see that recruits always fly zigzag into a target
site from far downwind (binoculars help). If an array of stations is
provided, recruits end up near the center of all - although a slight wind
blowing along a line of stations can alter an expected distribution.
Despite dancing, recruitment more than 400m downwind from a hive is
negligible unless many foragers make round trips and thereby provide an
aerial pathway of odor.
Crop-attached bees require no dancing for re-recruitment; they will
immediately return to their foraging area on the basis of an odor stimulus
alone. New recruits, by contrast, do not begin arriving in quantity until
almost an hour after foragers begin regular trips and increase in frequency
per unit time even if the number of dancing bees is held constant. Recruit
success is thus dependent more upon the cumulative number of forager trips
(with time and with odor accumulation in the hive) than upon the number of
foragers involved. Success rate depends upon odor concentration but not
upon Nasonov gland secretions at the food source or upon dance frequency in
the hive. Finally, recruits attending disoriented dances (dances without
direction information) can still find the "correct" site in the field.
No one seems to dispute the above known facts, so clearly researchers
have grossly neglected the role of odor in honey bee recruitment.
Furthermore, no one seems willing to provide a concise scientific statement
of the language hypothesis, one that can accommodate all known facts. For
those who wish to understand foraging ecology, an increased emphasis on the
role of odor in honey bee recruitment should be very rewarding.
One can find a quite complete 1990 summary of most of the above points
(Wenner & Wells, Anatomy of a Controversy: The Question of a "Language"
Among Bees. Columbia University Press) and a brief 1991 exposition
elsewhere (Wenner et al., American Zoologist 31:768-782).
********
I feel that one must give more than lip service to the role of odor,
since it is a very tangible, measurable, and usable communication channel.
Adrian
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