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Subject:
From:
Gavin Ramsay <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Sun, 26 Feb 2006 11:47:37 -0000
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Dear Ruth and All

I'll have to quote a little, so here's hoping that the moderators don't mind
:-)

> The authors provide few details, and only one track,
> about the tracked bees that presumably did search for
> attractive odors.

The authors provided plots of the tracks of around 36 bees, each of which
had been selected to have just watched a waggle dance for the first time.
The tracks are indeed in a fan-shape, with the centre of the fan directly in
line with the feeder (or, in the case of displaced bees, where the feeder
would have been).  Nothing can explain these direct, purposeful flights
except an understanding of the location of the food from the dance,
particularly when you consider the behaviour of the displaced bees and the
wind direction during the experiment.

All tracks get a little erratic in the region of the feeder, after they have
flown the approximate distance.  One describes a small semi-circle.  Another
(one of the displaced bees) just flies in a double s-shape at the end of its
run.  You can't decide from that that one bee was seeking a known odour and
the others were not.

> But the search is described as occurring in arcs. This
> is not at all the way regular recruits are expected to
> search for odors, according to v. Frisch's DL hypothesis.

I puzzled about what you mean here for a bit.  Most flights were direct and
essentially straight until the bees seemed to become unsure towards the end
of their flight when movements were more random.  But perhaps seven of the
displaced bees described a N-pointing arc at the end of their flight.  Why
just the displaced ones? At that point, their flights are taking them near
their hive (to the N), which they would have expected to have been far
behind them.  Presumably, as they recognised home and realised where they
were, they naturally curved towards the hive?

As I said previously, I have no doubt that odour is one of the cues that
bees use to find food.  I would have no problem too with believing that von
Frisch's understanding was imperfect.  For example, some of the research on
the air-borne transmission of sound which conveys information on the
geometry of the dance in the dark would be unknown to him.

> All the samples the authors obtained are, however,
> far too small to determine whether the tracks do,
> or do not show any semblance of the "fan-formation",
> expected according to the DL hypothesis.

I'm looking at the 36 tracks now.  It looks like a pretty good fan to me!

> Under the circumstances Riley et al. should have
> tested the DL hypothesis specifically under v. Frisch's
> conditions. Instead, they did not, and could not have
> done that at all.

Can I suggest that the authors were more concerned with developing an
experimental design that gave clear-cut answers one way or another?

> Do you still view that radar-tracking study as "science of
> the highest quality"?

Yes I do!

You also wrote about scent contaminating feeders, odours from mown grass,
and other such stuff.  The wind direction in the experiment - and the
behaviour of displaced recruits - shows that the bees in the study are not
following odour cues.

I have to thank you Ruth for raising this issue again.  I had been seriously
doubting the validity of the dance language - but your return to this forum
and another one prompted me to go and read some of the literature myself.
It is compelling.  Science often advances by folk challenging the
established view.  Sometimes the establish view collapses, and sometimes it
gets modified in the light of experience and emerges all the stronger.
Anyone wishing to decide for themselves what is happening here ought to read
the Riley paper.

all the best

Gavin.

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