[00:05.30]Lesson 85 1 Reading comprehension
[00:12.88]Read the text fast to find answers to these questions.
[00:19.54]1 How do honey bees communicate with each other?
[00:25.60]2 What are they able to tell each other?
[00:31.45]THE LANGUAGE OF HONEY BEES(1)
[00:37.30]There are many different varieties of bee.
[00:42.48]Some live in large groups like the honey bee,
[00:48.22]and make their nests in trees or holes in the rocks.
[00:53.79]Other types of bee make their nests in holes in the ground.
[01:00.16]There are also other varieties that do not live in groups at all.
[01:06.40]Among the different types of bee,
[01:11.08]it is the honey bee that has most interested scientists
[01:16.64]because of the"language"they use to communicate with each other.
[01:22.52]The development of the modern beehive in 1851
[01:28.87]made it possible to design experiments to research the language of honey bees.
[01:36.52]Professor Karl von Frisch,an Austrian scientist,
[01:42.77]spent many years of his life researching the amazing ways honey bees
[01:50.00]communicate in their dark hives.
[01:54.44]After working with bees for many years,
[01:59.20]Professor Von Frisch was puzzled by something he had noticed again and agin.
[02:06.64]When he placed little dishes of honey on a table,bees soon came.
[02:13.72]As soon as one bee discovered the honey,
[02:18.58]many more came to it one after another in a short time.
[02:25.24]It seemed that one bee was able to communicate the news of food
[02:31.72]to other bees in its hive.How was this possible?
[02:38.07]To find out,Von Frisch built special hives,each with only one honeycomb.
[02:46.01]He built a glass wall through which he could watch what went on inside.
[02:52.77]In order to tell the bees apart,he painted some bees with little spots of colour.
[03:01.60]When a marked bee returned to the hive from the feeding table,
[03:08.16]Von Frisch watched through the glass.
[03:12.84]To his astonishment,
[03:16.78]the bee began to perform a dance on the surface of the honeycomb.
[03:23.65]First it made a circle to the right,then to the left.
[03:30.31]It repeated these circles over and over again.But that was not all.
[03:39.06]The dance seemed to excite the surrounding bees.
[03:44.84]They trooped behind the first dancer,copying its movements.
[03:52.10]Then the left the hive and went to the feeding place.
[03:58.45]The circle dance seemed to communicate news of food.But what else?
[04:06.70]Von Frisch wanted to find out
[04:11.45]whether the dance told them how far away the feeding place was.
[04:18.30]So he set up two feeding places.One was close to the hive.
[04:26.14]The other was much farther away from the hive.
[04:31.46]He marked all the bees that came to the nearby feeding place blue,
[04:38.23]and all the bees that went to the faraway place were marked red.
[04:45.68]When the bees came back to the hive,Von Frisch saw a curious sight.
[04:53.83]All the bees that had been at the nearby place were doing the circling dance.
[05:01.66]All the bees that had been at the distant feeding place
[05:07.72]were doing a completely different dance,a wagging dance.
[05:13.65]The dancer ran in a straight line,wagging from side to side.
[05:20.18]Then it turned in a semicircle,ran straight again,
[05:26.45]and turned in another semicircle to the opposite side.
[05:32.30]It kept repeating the"steps"over and over.Things were clear now.
[05:39.88]The circle dance meant that food was near.
[05:44.92]The wagging dance meant that food was far away.
[05:50.80]Lesson 86
[06:00.75]1 Reading comprehension
[06:05.11]Read the text fast to find the answer to this question:
[06:12.17]What else did Von Frisch notice about the wagging dance?
[06:18.93]THE LANGUAGE OF HONEY BEES(2)
[06:24.57]But then another question came up.
[06:30.14]Did the wagging dance tell the bees how far away the food was?
[06:37.71]To answer this question
[06:41.55]Von Frisch and his coworkers set up a feeding place close to the hive.
[06:49.21]Then they slowly moved it farther and farther away.
[06:55.16]Back at hte hive they watched the wagging dance closely.
[07:01.22]With a stopwatch,
[07:04.88]they counted how many times the bees repeated the dance during one minute.
[07:12.54]They discovered that the farther away the feeding station was,
[07:18.78]the slower the dance was.
[07:23.32]So another astonishing fact came to light .
[07:28.99]The number of wagging dances per minute
[07:33.96]told the exact distance to the feeding place.
[07:39.00]They also found out that bees fly a maximum distance
[07:45.97]of 3.2 kilometres between their hive and a feeding place.
[07:52.63]Next Von Frisch thought that bees needed to know more than just the distance
[08:00.29]to a faraway place.
[08:03.63]He thought they needed to know the direction to it.
[08:08.31]He set out to discover whether the wagging dance showed direction.
[08:15.26]He put a glass dish with sugar water and honey to the west of the hive.
[08:22.91]A marked bee fed itself from the dish and returned to the hive.
[08:30.17]Soon,the bees in the hive flew out.They flew right to the dish.
[08:37.43]Then Von Frisch moved the dish to the east of the hive
[08:43.21]and waited for a marked bee to feed.
[08:48.07]Again the bees flew right to the dish.
[08:53.32]How did the bees know exactly in which direction to fly?
[08:59.27]Von Frisch watched the wagging dance very carefully.
[09:05.83]He noticed that the straight part of the dance was different in the afternoon
[09:12.67]from what it had been in the morning.
[09:17.11]It soon became clear that the straight part of the dance
[09:22.86]changed when the sun's position changed.
[09:27.69]If the feeding place was toward the sun,
[09:32.84]the dancer headed straight upward during the straight part of the wagging dance.
[09:39.92]If the feeding place was away from the sun,
[09:45.06]the straight part of the wagging dance pointed downward.
[09:50.63]The wagging dance of the honey bee,therefore,
[09:55.36]did show the direction of a feeding place.
[10:00.03]When honey bees have discovered a feeding place,
[10:05.07]they fly directly to it from the hive.
[10:09.83]After a short time a line of bees fly to and from the hive like a thin stream.
[10:18.89]Centuries ago,the word"beeling"
[10:24.35]was made to describe this thin line of bees flying through the air.
[10:30.62]From this we get the expression"to made a beeline for someone or something",
[10:38.17]which means to go quickly along a straight direct course for someone or something.
[10:46.64]For his lifetime's work in studying the communication of animals,
[10:52.80]including honey bees,
[10:56.74]Professor Karl von Frisch was given a Nobel Prize in 1973,
[11:04.50]which he shared with two other scientists.He died in 1982 |