Why the insect brain is so incredible - Anna Stöckl

譯者: Yeh Andy 審譯者: 易帆 余

The human brain is one of the most sophisticated organs in the world,

人類的大腦是世界上 最複雜的器官之一，

a supercomputer made of billions of neurons

由數十億個神經元所組成的超級電腦，

that processes and controls all of our senses, thoughts, and actions.

可以控制和處理所有的 感官、想法和動作。

But there was something Charles Darwin found even more impressive:

但讓查爾斯·達爾文 感到更加印象深刻的是：

the brain of an ant,

螞蟻的大腦，

which he called one of the most marvelous atoms of matter in the world.

被達爾文稱為世界上 最不可思議的原子構成物之一。

If you find it hard to believe that something so tiny

如果你很難相信這麼渺小的生物

could have a complex brain,

擁有這麼複雜的大腦，

you're not alone.

這很正常。

In his project to classify and describe all living things,

在計畫對所有生物進行分門別類時，

Swedish naturalist Carl Linnaeus assumed insects had no brains at all.

瑞典生物學家卡爾·林奈 認為昆蟲完全沒有大腦。

He was wrong, but understandably so.

他雖然是錯的，但可以理解。

Insect brains are not only miniscule,

昆蟲的大腦不僅相當微小，

but in many respects, they function differently than our own.

而且還在許多方面上， 有著和我們截然不同的功能。

One of the most noticeable differences

其中最明顯的差異

is that an insect that loses its head can still walk,

就是失去頭的昆蟲仍然可以走路，

scratch itself,

自己抓癢，

breathe,

呼吸，

and even fly.

甚至飛行。

This is because while our nervous system works like a monarchy,

這是因為我們的神經系統 就像中央集權式的，

with the brain calling the shots,

由大腦發號施令，

the insect nervous system works more like a decentralized federation.

而昆蟲的神經系統 比較像是分權的聯邦制。

Many insect activities, like walking or breathing,

昆蟲的活動，如散步或呼吸，

are coordinated by clusters of neurons, also known as ganglia,

都由在牠們身上的神經叢，

也叫做神經結，遍佈全身而調控的。

along their bodies.

Together with the brain, these local ganglia form the insect nervous system.

這些地區性神經結和大腦 一起形成昆蟲的神經系統。

While an insect can do a lot with just its local ganglia,

雖然昆蟲可以只用 局部的神經結做很多事情，

the brain is still crucial for its survival.

大腦仍然是其生存的關鍵。

An insect's brain lets it perceive the world through sight and smell.

昆蟲的大腦可以讓它透過 視覺和嗅覺來感覺世界。

It also chooses suitable mates,

還有擇偶的功能，

remembers locations of food sources and hives,

記住食物來源和巢的位置，

regulates communication,

管理溝通，

and even coordinates navigation over huge distances.

甚至協調導航的能力 到達遠距離以外的目標。

And this vast diversity of behaviors

而這些多樣性的行為

is controlled by an organ the size of the head of a pin,

都是由一個像針頭大小一樣

with less than one million neurons,

不到一百萬個神經元的器官所控制，

compared to our 86 billion.

不同於我們有八百六十億個。

But even though the insect brain is organized very differently from ours,

即使昆蟲大腦的結構 與我們很不相同，

there are some striking similarities.

但仍有一些驚人的相似之處。

For example, most insects have smell detectors on their antennae,

例如，大多數昆蟲用 他們的觸角感覺氣味，

similar to those found in human noses.

與我們人類的鼻子功能相似。

And our primary olfactory brain regions look and function rather similarly,

還有兩者的初級嗅覺腦區的 外觀和功能都十分類似，

with clusters of neurons activated and deactivated in precise timing

它會在一個精準的時間內 激活或鈍化神經元群

to code for specific scents.

來辨別某一種特殊氣味。

Scientists have been astonished by these similarities

科學家對這些相似之處感到驚訝，

because insects and humans are not very closely related.

因為昆蟲和人類相當 不具有親緣關係。

In fact, our last common ancestor was a simple worm-like creature

事實上，我們最後的共同祖先

that lived more than 500 million years ago.

是一個生活在五百萬前 簡單的蟲狀生物。

So how did we end up with such similar brain structures

然而為什麼我們最終具有 如此相似的大腦結構，

when our evolution took almost entirely different paths?

即使我們彼此的演化之路 幾乎完全不同？

Scientists call this phenomenon convergent evolution.

科學家稱這種現象為「趨同演化」。

It's the same principle behind birds, bats, and bees separately evolving wings.

這是鳥、蝙蝠與蜜蜂 各自演化出翅膀的主要原因。

Similar selective pressures can cause natural selection

相同的選擇壓力會引起天擇，

to favor the same evolutionary strategy

並在不同物種的演化路程中， 促成相同的演化策略。

in species with vastly different evolutionary pasts.

By studying the comparison between insect and human brains,

透過研究比較昆蟲和人類的大腦，

scientists can thus understand which of our brain functions are unique,

科學家因此可以了解我們的大腦 哪些功能是獨一無二的，

and which are general solutions to evolutionary problems.

哪些是演化問題的常態性解決方法。

But this is not the only reason scientists are fascinated by insect brains.

但這不是科學家對 昆蟲的大腦著迷的唯一原因。

Their small size and simplicity makes it easier to understand

他們的小尺寸和簡單性， 使其更容易理解

exactly how neurons work together in the brain.

神經元究竟是如何 在大腦中一起工作的。

This is also valuable for engineers,

這對研究昆蟲腦部來幫助設計的 工程師來說是很有價值的，

who study the insect brain to help design control systems

像是設計自動駕駛飛機、 微型探勘救援蟑螂機器人等。

for everything from self-flying airplanes to tiny search-and-rescue roach bots.

因此，尺寸和複雜性並不是 最令人印象深刻的事情。

So, size and complexity are not always the most impressive things.

The next time you try to swat a fly,

下一次你試圖拍打一隻蒼蠅時，

take a moment to marvel at the efficiency of its tiny nervous system

花一點時間讚嘆一下 牠那微小神經系統的效率，

as it outsmarts your fancy brain.

因為它比你的腦袋瓜還要聰明呢。