生命之色（2021）

But there's a hunter here that exploits this relationship.
但是这里还有一个猎人想要利用这种关系
A crab spider.
一只蟹蛛
She's tiny, no bigger than a fingernail,
这只雌蛛很小 只有指甲盖大小
and she's waiting for her prey.
它正在等待猎物
Almost the same colour as her background,
它几乎和背景颜色一样
she's virtually invisible.
几乎是隐身了
No more honey for her.
这只蜜蜂再也采不到蜜了
But, of course,the spider's hunting grounds are limited.
但是 蜘蛛的猎场当然也会受到限制
Not all flowers are yellow.
并非所有的花都是黄色的
When she sits on a pure white petal,
当雌蛛呆在纯白色的花瓣上时
she immediately becomes obvious.
就会变得很明显
She will never catch a bee while she's so conspicuous.
这么显眼的它可抓不住蜜蜂
So, she changes.
所以 它改变了
She breaks down the yellow pigments in the outer layer of her skin
它褪去了皮肤外层的黄色♥色♥素
to expose special crystals underneath
展现出下方的特殊透明体
that act like tiny mirrors and reflect the light.
像小镜子一样反射着光线
It may take a few days,
整个过程需要几天的时间
but she turns from yellow
但是 它还是从黄色
to white.
变成了白色
Changing colour isn't the spider's only trick.
改变颜色不是蜘蛛的唯一手段
There's more to this story than meets the eye.
事情并不像表面上那样简单
Bees can see coloursxa0thatxa0we cannot.
蜜蜂能看到人类看不到的颜色
They can see ultraviolet colours.
它们能看到紫外线的颜色
As they come in to land on a flower,
当它们落到花朵上
they use special sensors
会用特别的感官
that can detect ultraviolet patterns on the flower's petals.
来探测花瓣上的紫外线图案
We can see them too with our special UV camera.
我们也可以用特殊的相机看到这些图案
There are dark lines on the petals
花瓣上有一些暗色线条
that mark the landing strips for the bees,
标记出了指引蜜蜂们找寻花蜜的
guiding them to the nectar.
着陆带
The spider, however,
然而 这只蜘蛛
has developed a way to exploit these signals.
已经找到了方法来利用这些信♥号♥♥
Watching her with our UV camera,
通过紫外线相机进行观察
we can see that she reflects ultraviolet light,
可以看到雌蛛反射了紫外线光线
so she appears even more conspicuous sitting on a flower.
所以它在花朵上变得更加显而易见
This extra brilliance acts as a kind of super signal,
这种额外的光亮就像是一种超级信♥号♥♥
which the bee can't resist.
让蜜蜂们无法抗拒
And the spider benefits.
蜘蛛也因此受益
In fact, the bees are more than three times as likely
事实上蜜蜂降落在这些有蜘蛛花朵上的概率
to visit flowers with UV-reflecting spiders on them
比那些没有蜘蛛的
than those without.
要高出三倍
The crab spider uses a sophisticated range of colours
蟹蛛会用各种复杂的颜色
to deceive its prey.
来欺骗猎物
But colour can also be used in a simpler,even more surprising way
但颜色也会通过更简单 甚至更令人惊讶的方法
to confuse the enemy.
来迷惑敌人
And on the plains of Kenya's Masai Mara,there's one animal
在肯尼亚马赛马拉的草原上
that uses just two colours
有一种动物会只用两种颜色
to outwit its predators.
来瞒骗它的捕食者
The zebra.
斑马
Its black and white coat makes it extremely obvious
在开阔的草原上吃草时
as it grazes out on the open grasslands.
它的黑白外表显得格外明显
Other grazers have softer,gently varied colouration,
其它的食草动物颜色更加柔和 色差较小
which blends with their background.
融入了环境
So it seems strange that zebras,apparently, do quite the opposite.
所以 很奇怪的是斑马们的做法显然正好相反
Particularly as they live in a world where there are so many hunters.
特别是它们所处的环境中有那么多猎手
Lions,
狮子…
hyenas,
土狼…
and cheetah.
还有猎豹
The boldly striped zebra seem to be asking for trouble.
大胆的斑马似乎是在自找麻烦
How do they get away with it?
它们要如何侥幸逃生？
The question has been hotly debated by naturalists for centuries.
博物学家已经就这个问题讨论了好几个世纪
New research is now suggesting an answer.
新的研究给出了一个答案
To understand how it might work,
为了理解可能的原理
we need to consider the particular colours involved.
我们需要考虑到所涉及的特定颜色
Black and white are two of the most contrastingxa0colours.
黑白是对比度最高的两种颜色
And no two animals have exactly the same pattern,
而且两只斑马不会有完全一样的图案
so each has a unique whole-body fingerprint.
所以 每匹斑马的全身纹路都各不相同
But when the zebras move,
但是当斑马移♥动♥时
the stripes create confusion.
条纹会造成混乱
It's known as motion dazzle.
也被称为“动态眩晕”
And it makes it difficult for a predator to keep focused on one particular target.
捕食者很难将注意力集中在某一个目标上
The cheetah, looking for a meal.
这只猎豹在寻找食物
To make a successful strike,
为了发出成功一击
they must judge the distance accurately
它们必须精确地判断距离
and time it perfectly.
完美地安排好时机
So if a zebra's stripes
所以如果斑马的条纹能迷惑猎豹
just for a few crucial seconds,
哪怕只有几秒钟时间
it may escape.
它就有可能逃生
But there's another threat on these plains.
但这些草原上还有另一个威胁
Flies.
苍蝇
They are a real pest here.
它们真的是这里的害虫
They're not just a nuisance.
它们不仅是讨厌
They carry diseases,
还会携带病菌
some of which are particularly nasty,
有一些会很严重 甚至致命
Despite the huge numbers of flies,
尽管有大量的苍蝇
the zebras appear remarkably untroubled by them.
斑马却看起来似乎并不怎么会受到干扰
There are plenty of flies around…
周围有很多的苍蝇…
but few actually land on the zebra.
但很少会落在斑马身上
One theory is that the black and white stripes
有一个理论认为黑白的条纹
make it difficult for flies to judge the distance.
会让苍蝇很难判断距离
To test this idea,
为了检验这个理论
scientists counted how many flies landed on animals
科学家们计算了有多少苍蝇
with gently graded colours
落在了柔和色差的动物身上
and how many landed on the zebras' stripes.
又有多少落到了斑马的条纹上
They found that four times fewer flies landed on zebras
他们发现 在斑马身上停留的苍蝇
than on their more plainly coloured neighbours.
比那些寻常颜色的邻居们少了四倍
Why should that be?
怎么会这样呢？
It seems it's another consequence of those stripes.
看来又是条纹的功劳
They confuse the flies
在苍蝇还没想好停在哪里时
as they make their final approach to settle.
条纹就迷惑了苍蝇
Perhaps this creates a visual blurring for the flies,
也许是这些图案给苍蝇造成了视觉模糊
much as it does for a cheetah.
就像它们对猎豹那样
So it seems that the zebras' patterns of stripes
所以斑马的条纹图案
creates an optical effect that helps protect them from enemies,
似乎形成了帮助它们逃离敌人的视觉效果
both large and small.
大小敌人均如此
While zebras use different patterns to confuse their enemies,
斑马用不同图案来迷惑敌人
on the island of Cuba,
古巴的岛屿上
there are smaller and rather slower-moving creatures
有一些体型更小移♥动♥也相对更慢的生物
that do a similar thing.
也在做着做类似的事
This is Polymita picta,
这就是叉线海明蜗牛
a Cuban painted snail.
一种古巴的彩带蜗牛
You might think that this one is an exceptionally lovely,
你可能会觉得这只蜗牛特别可爱
eye-catching individual.
非常引人注目
But it's not, by any means,
但无论从什么角度来说
the only snail that is so beautifully decorated.
它都不是唯一装饰得这么漂亮的蜗牛
No two individuals are exactly the same,
没有两只蜗牛会长得一模一样
yet all these belong to the same species.
但它们都属于同一物种
There are also five other species of Polymita here.
这里还有五种叉线海明蜗牛
Each snail has its own unique combination
每只蜗牛都有自己独特的
of colours and stripes.
颜色和条纹
Their colours come from their diet.
它们的颜色来自于饮食
Lichen and mosses rich in minerals
地衣和苔藓中富含矿物质
that give the shells these stunning colours.
让它们的壳变成了闪耀的颜色
They differ according to the particular mix of plants
每只蜗牛所吃植物组合各有不同
that each snail has been eating.
变得也各有差异
Variations of individuals within a species is not uncommon in the natural world.
自然界里同一物种的不同个体出现如此多变化并不常见
It's called polymorphism.
这叫做多态性
But it's particularly marked among Cuban snails.
但这个现象 在古巴蜗牛中特别明显
Some scientists believe that the variation in itself
有些科学家认为 这种差异本身
may be a kind of defence against predators.
也许也是一种对抗捕食者的防御行为