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The Dancing Bees
To attract bees a simple device was used, just a sheet of paper
liberally smeared with honey
and placed on the experimental table about 20 m from the hive. It may be an hour or two before,
by chance, a bee discovers this bounty, but if she be marked with a spot of paint it will he noticed
that she will soon return to the spot after taking her load of honey back to the hive, and within
minutes dozens of other bees will also arrive. If we trace their
origin we shall find that they came
from the same colony as the first bee.
If a glass-sided observation hive be used, it will be seen that the
foraging bee first transfers
her load of honey to "house bees", whose job it is to feed others or store honey in waxen cells. She then begins to perform a kind of "round dance". On the part of the comb where she is sitting
she starts whirling around in a narrow circle, constantly changing her direction, dancing
clockwise and anticlockwise in quick succession, describing one or two circles in each direction.
Her enthusiasm is communicated to several other bees, who follow her every movement and
repeat it with great excitement before rushing to the entrance to leave the hive. They return
within minutes with a load of honey themselves, and then dance in the same manner, thus multi-
plying the number of bees flying to the honey-smeared paper. If this experiment be repeated with
the table set up at various distances further from the hive, and the dances watched, it will be
noted that they begin to change from a "round dance" to a "wagging dance" when the table
is over 50 m away, and for distances of about 90 m and over the foraging bee will dance in a
totally different manner. In this new dance the bee runs around a narrow semi-circle, makes a
sharp turn and runs back in a straight line to her starting point; then she describes another semi-
circle, this time in the opposite direction, thus completing a full circle, before once more returning
to her starting point in a straight line. The other characteristic feature distinguishing the new
dance from the former "round dance" is a rapid wagging of the bee's abdomen performed only
during her straight run. This wagging dance commands just as much attention among the bees
following her movement as did the round dance.
When, in a new series of experiments, the feeding place was gradually moved up to 10 km
away, it was observed that the straight "waggle run" became more vigorous and prolonged, with
the turn following at longer and longer intervals. Using a stop-watch it was found that a dancing
bee traveled along the straight part of the run between 9 and 10 times in 15 seconds if the feeding
place were 100 m from the hive, 6 times at a distance of 500 m, 4 times at 1000 m, twice at
5000 m and barely more than once at 8 to 10 km. The agreement between measurements taken
on different but windless days, in different years with different colonies in different places, is
quite amazing. In windy weather the timing of dances is altered, for example if bees have to fly
against the wind to reach the honey source, then the distance is treated as longer and
vice versa.
Experiments with food supplies placed on the same angular bearing but at different distances
have confirmed that bees fly to the original source, not to equally good sources further or even
nearer. Thus bees clearly have a remarkable sense of time, by means of which they are aware
when they should reach their destination.
It would be of little use to the bees if they knew that a large tree was in full flower 2 km
away but were ignorant of its direction: the wagging dance gives this as well. Inside the hive an
upward wagging run means that the feeding place lies directly towards the sun; a downward
wagging run indicates the opposite direction; an upward wagging run 60° to the left of vertical
indicates food to be sought in a direction 60° to the left of the sun's direction and so on. A
direction learned by other bees, in the semi-darkness of a hive in a vertical direction, is
transferred to an angular bearing on the sun in a horizontal direction once they are outside the
hive. |
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Questions |
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1. |
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Why should it perhaps be as long as an hour before the first bee arrives
at the experimental table, yet after that dozens more arrive within a
few minutes ? |
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2. |
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Explain why it should be necessary for bees to have two different types
of dance, in respect of honey sources at different distances from the
hive ? |
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3. |
(a) |
Explain fully the meaning of the following words or phrases as they are
used in the passage : (i) liberally, (ii) origin, (iii) foraging, (iv)
characteristic, (v) vice versa, (vi) angular bearing |
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(b) |
Write six short sentences, using each of the
words or phrases (i) to (vi) to illustrate their meaning. Your sentences
should not deal with the subject matter of the passage. |
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4. |
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In about 150 words explain exactly how a bee learns the direction of,
and navigates successfully to a field of flowers 4 km away from the hive
on a calm sunny day. What difference would it make if there were a
moderate breeze blowing from the hive towards the flowers ? |
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5. |
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Do you think that it would make any difference if the hive were to be
turned around so that the entrance pointed in a different direction,
halfway through the experiment ? Explain your reasoning clearly. |
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Answers |
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1. |
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The first bee discovers the location of the honey by chance, not by
smell or vision. However, when she has taken honey to the hive and
delivered it to the bees which store it and feed others, she returns
quickly to the source. Meanwhile she has indicated to other bees the
whereabouts of the honey by means of a certain kind of 'dance' within
the hive. The dance indicates distance and location. Other bees watch,
then follow, and on their return communicate the whereabouts of the
honey to other bees. Thus, a large number will arrive in a short time. |
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2. |
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The change in dance-style indicates the distance between the hive and
the honey-source. Up to 50m she does narrow circles, clockwise then
anti-clockwise. From 50m to 90m she does a 'wagging dance' and over 90m
a different kind. this dance is a clockwise semicircle with a diameter
return to the start-point, followed by the same, anti-clockwise. Thus
she describes a complete circle. The 'wagging' dance frequency is in
inverse ratio to the distance. |
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3. |
(a) |
(i) liberally -- freely, generously |
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(ii) origin -- source, the hive they came from |
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(iii) foraging -- searching for food |
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(iv) characteristic -- identifying, special |
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(v) vice versa -- the other way round |
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(vi) angular bearing -- a direction a certain number of degrees left or
right of the sun's position |
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(b) |
(i) He gives liberally to every charitable cause |
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(ii) Etymology is the study of the origin of words |
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(iii) In the old days, soldiers were sent foraging for food |
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(iv) A quick temper is said to be a characteristic of people who have
red hair |
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(v) There was dislike between Alan and his teacher, and vice versa |
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(vi) I shall need an angular bearing if I am to find that particular
house by night-compass |
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4. |
The bee would learn the distance by watching
another which had already been to the field. This bee would indicate
4000m by traveling along the straight part of the 'wagging' run only
about three times. The direction would be indicated by an upward wagging
if towards the sun and a downward wagging if away. The run itself points
to the angular bearing to the sun. With the breeze the time factor would
decrease, making the journey notionally less. This would increase the
demonstrating bee's number of straight line movements marginally to say
3 1/2 within 15 seconds. ( 97 words ) |
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5. |
There is no relationship between the
honey-source and the direction in which the hive is facing. The first
bee finds the source by chance and returns to the hive, after which she
communicates the information to other bees by one of two types of dance,
depending on distance. Both dances indicate direction by means of the
alignment of the runs to the position of the sun. with this information
the bees will emerge from the hive in whatever position it is place and
at once fly off on the correct bearing. |
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