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Nature's Most Destructive Swarm | 20 Years of Planet Earth | BBC Earth
Nature's Most Destructive Swarm | 20 Years of Planet Earth | BBC Earth
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ترجمة (45)
0:23
There is no other species on the planet
0:25
that responds as quickly and as
0:27
dramatically to the good times. s as the
0:30
desert locust.
0:32
Eggs that have remained in the ground
0:34
for 20 years begin to hatch.
0:49
The young locusts are known as hoppers,
0:51
for at this stage they're flightless.
0:54
They find new feeding grounds by
0:57
following the smell of sprouting grass.
1:06
Normally it takes 4 weeks for hoppers to
1:09
become adults, but when the conditions
1:11
are right, as now, their development
1:13
switches to the fast track.
1:21
As the vegetation in one place begins to
1:23
run out, the winged adults release
1:25
phenommones, scent messages, which tell
1:28
others in the group that they must move
1:30
on.
1:42
And when groups merge, they form a
1:45
swarm.
2:08
An adult locus eats its entire body
2:11
weight every day, and a whole swarm can
2:13
consume literally hundreds of tons of
2:16
vegetation.
2:19
They have to keep on moving.
2:22
The swarm travels with the wind. It's
2:25
the most energy saving way of flying.
2:31
Following the flow of wind means that
2:34
they're always heading toward areas of
2:36
low pressure, places where wind meets
2:38
rain and vegetation starts to grow.
2:44
As they fly, swarms join up with other
2:47
swarms to form gigantic plagues several
2:50
billion strong and as much as 40 m wide.
2:56
They will consume every edible thing
2:58
that lies in their path.
3:13
This is one of planet Earth's greatest
3:15
spectacles.
3:17
It's rarely seen on this scale, and it
3:19
won't last long. Once the food has gone,
3:23
the steady roar of a billion beating
3:25
locust wings will once again be replaced
3:29
by nothing more than the sound of the
3:31
desert wind.
