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TEDWomen 2015

Marlene Zuk: What we learn from insects’ kinky sex lives

マレーネ・ズク: 虫たちの倒錯したセックスライフから学べること

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マレーネ・ズクは喜びと決然たる態度をもって昆虫の研究に臨んでいます。閃きに満ちた滑稽なトークで彼女は、驚くべき昆虫たちのセックス及び、その衝撃的とすらいえる真実について紹介します。

- Evolutionary biologist
Marlene Zuk studies insect behavior -- and how humans use animal behavior to think about how we behave ourselves. Full bio

So, people are more afraid of insects
than they are of dying.
皆さん 昆虫を怖がります
死ぬよりも
00:13
(Laughter)
(笑)
00:18
At least, according to a 1973
"Book of Lists" survey
『ブック・オブ・リスト
ー世界なんでもランキング』の1973年版は
00:20
which preceded all those online best,
worst, funniest lists that you see today.
ベストもワーストも面白ネタも載っている
ランキング本なんですが
00:25
Only heights and public speaking
それによると
高い所と大勢の人前での演説だけが
00:32
exceeded the six-legged
as sources of fear.
虫よりも
恐怖ランキングの上に来るそうです
00:35
And I suspect if you had put
spiders in there,
ここにクモも付け加えれば
00:39
the combinations of insects and spiders
would have just topped the chart.
虫とクモの合計なら
一気に1位になったでしょう
00:43
Now, I am not one of those people.
さて私はそういう人々とは違い
00:48
I really love insects.
本当に昆虫が好きです
00:50
I think they're interesting and beautiful,
昆虫はとにかく面白くて 美しいし
00:53
and sometimes even cute.
かわいいとすら思うときも
00:57
(Laughter)
(笑)
00:58
And I'm not alone.
私だけではありません
01:00
For centuries, some
of the greatest minds in science,
チャールズ・ダーウィンから
E.O.ウィルソンまで
01:01
from Charles Darwin to E.O. Wilson,
何世紀もの間 偉大な科学者の中には
01:05
have drawn inspiration from studying
some of the smallest minds on Earth.
地上で最小の生命への研究から
着想を得てきた人達がいます
01:08
Well, why is that?
なぜでしょう?
01:14
What is that keeps us
coming back to insects?
昆虫の何が私達を
惹きつけてやまないんでしょうか?
01:16
Some of it, of course, is just the sheer
magnitude of almost everything about them.
もちろん その理由の一つに 圧倒的な
昆虫の数が挙げられるでしょう
01:20
They're more numerous
than any other kind of animal.
彼らの個体数は他のどんな動物よりも多く
01:24
We don't even know how many species
of insects there are,
未だに種全体の数すらつかめていません
01:27
because new ones
are being discovered all the time.
絶えず新種が発見されていますしね
01:30
There are at least a million,
maybe as many as 10 million.
少なくとも100万種
あるいは1,000万種かもしれません
01:33
This means that you could have
an insect-of-the-month calendar
たとえば「今月の虫」カレンダーを作ったとしたら
01:37
and not have to reuse a species
for over 80,000 years.
同じ種を使い回す事なく
8万年分ができるわけです
01:41
(Laughter)
(笑)
01:45
Take that, pandas and kittens!
思い知ったか パンダと子猫!
01:48
(Laughter)
(笑)
01:50
More seriously, insects are essential.
真面目な話
昆虫は欠くべからざる存在です
01:52
We need them.
私達には昆虫が必要です
01:55
It's been estimated
that 1 out of every 3 bites of food
私達が口にする食料のおよそ1/3は
01:57
is made possible by a pollinator.
花粉を運ぶ昆虫のおかげで
手に入るのです
02:00
Scientist use insects to make fundamental
discoveries
科学者は昆虫を使って
あらゆる重要な発見—
02:04
about everything from the structure
of our nervous systems
ヒトの神経系の構造から
遺伝子やDNAの働きまで
02:08
to how our genes and DNA work.
解明してきました
02:11
But what I love most about insects
でも私が昆虫好きな一番の理由は
02:14
is what they can tell us
about our own behavior.
昆虫から ヒトの行動を
学ぶことができるからです
02:16
Insects seem like they do
everything that people do.
昆虫はヒトと似た行動をします
02:19
They meet, they mate,
they fight, they break up.
出会い、連れ添い、ケンカし、別れます
02:22
And they do so with what looks
like love or animosity.
しかもそこには愛や恨みのような物さえあります
02:26
But what drives their behaviors is really
different than what drives our own,
しかしその行動の動機は
ヒトの動機とは全く異なり
02:31
and that difference
can be really illuminating.
その違いにこそひらめきがつまっています
02:36
There's nowhere where that's more true
そのことが最も現れる領域は
02:40
than when it comes to one
of our most consuming interests -- sex.
私達の最大の関心事の1つ
セックスです
02:42
Now, I will maintain.
and I think I can defend,
さて ある主張を
論じていこうと思います
02:46
what may seem like a surprising statement.
えっ と思われるかもしれませんが
02:48
I think sex in insects is more
interesting than sex in people.
「昆虫のセックスのほうが
人間のより面白い」
02:52
(Laughter)
(笑)
02:56
And the wild variety that we see
そこに見られる途方も無い多様さは
02:58
makes us challenge
some of our own assumptions
私達のオス・メスの定義に対する
03:01
about what it means to be male and female.
思い込みを揺さぶるものです
03:04
Of course, to start with,
もちろん 初めに断っておきますが
03:07
a lot of insects don't need
to have sex at all to reproduce.
生殖のためのセックスが
全く必要ない昆虫は多くいます
03:09
Female aphids can make little, tiny clones
of themselves without ever mating.
雌のアブラムシは番(つがい)にならずに
小さなクローンを作ることができます
03:12
Virgin birth, right there.
まさに処女懐胎!ほらそこにも
03:17
On your rose bushes.
あなたの育てたバラの繁みで
03:18
(Laughter)
(笑)
03:20
When they do have sex,
昆虫のセックスと言えば
03:23
even their sperm is more
interesting than human sperm.
昆虫は精子さえ 人間のより面白いです
03:25
There are some kinds of fruit flies
ショウジョウバエの中には
03:28
whose sperm is longer
than the male's own body.
精子がオスの体長よりも長い種がいます
03:30
And that's important because the males
use their sperm to compete.
これが重要です
なぜならオスは精子で競うからです
03:34
Now, male insects do compete with weapons,
like the horns on these beetles.
カブトムシのツノのように
オスの昆虫は武器で競いますが
03:38
But they also compete
after mating with their sperm.
番になった後も精子で競うんです
03:43
Dragonflies and damselflies have penises
that look kind of like Swiss Army knives
トンボやイトトンボのオスは
まるで十徳ナイフを全部広げたような
03:48
with all of the attachments pulled out.
ペニスを持っています
03:53
(Laughter)
(笑)
03:55
They use these formidable devices
like scoops,
彼らはこの恐るべき道具を
スコップのように使って
03:57
to remove the sperm from previous males
that the female has mated with.
メスの体内から
前に交尾したオスの精子を取り除きます
04:02
(Laughter)
(笑)
04:06
So, what can we learn from this?
さて このことから我々が学べる事は?
04:08
(Laughter)
(笑)
04:11
All right, it is not a lesson in the sense
of us imitating them
いいですか この話は我々が昆虫を真似るとか
04:17
or of them setting
an example for us to follow.
我々が見習うべき何かがある
ということではありません
04:22
Which, given this,
is probably just as well.
この話も多分 そういうものではないですね?
04:25
And also, did I mention sexual cannibalism
is rampant among insects?
それと 昆虫界の性的カニバリズムの大流行
の話はしましたっけ?
04:29
So, no, that's not the point.
そういうことじゃありません
04:32
But what I think insects do,
でも昆虫たちの行動は
04:35
is break a lot of the rules
that we humans have about the sex roles.
人間が性別ごとに割り当てた役割を
ことごとく破るんです
04:36
So, people have this idea that nature
dictates kind of a 1950s sitcom version
50年代のホームコメディめいた男女のあり方を
自然界がそっくり表していると
04:43
of what males and females are like.
私達が思い込んでいるフシがあります
04:48
So that males are always
supposed to be dominant and aggressive,
オスはいつも支配的で攻撃的であり
04:50
and females are passive and coy.
メスはいつも受け身でシャイだと
04:54
But that's just not the case.
でもそれは偏った見方です
04:55
So for example, take katydids,
例えば キリギリスは
04:58
which are relatives of crickets
and grasshoppers.
コオロギやバッタの仲間ですが
05:00
The males are very picky
about who they mate with,
オスはつがいの相手選びにやけに慎重で
05:03
because they not only transfer
sperm during mating,
なぜなら交尾では精子のみならず
05:07
they also give the female
something called a nuptial gift.
メスに婚姻ギフトと
呼ばれるものも渡すからです
05:10
You can see two katydids
mating in these photos.
この写真では2匹の
キリギリスが写っていますね
05:14
In both panels,
the male's the one on the right,
両方とも向かって左がオスです
05:18
and that sword-like appendage
is the female's egg-laying organ.
剣のように突起しているのが
メスの産卵管です
05:20
The white blob is the sperm,
白い泡が精子
05:25
the green blob is the nuptial gift,
そして緑の泡が婚姻ギフトで
05:27
and the male manufactures
this from his own body
オスはこれを
自分自身の身体から生産します
05:31
and it's extremely costly to produce.
この婚礼ギフトは非常に高くつきます
05:34
It can weigh up to a third
of his body mass.
重さにして
体重の1/3になることもあります
05:36
I will now pause for a moment
and let you think about
ここで一旦考えてみましょう
05:39
what it would be like if human men,
every time they had sex,
もし人間の男がセックスのたびに
05:42
had to produce something
that weighed 50, 60, 70 pounds.
20〜30kgの何かを
生産しなきゃならないとしたら
05:46
(Laughter)
(笑)
05:52
Okay, they would not be able
to do that very often.
今ほど頻繁には出来なくなりますね
05:56
(Laughter)
(笑)
05:59
And indeed, neither can the katydids.
まさに キリギリスにも同じことが言えます
06:01
And so what that means
つまりキリギリスのオスは
06:04
is the katydid males are very choosy
婚姻ギフトを贈る相手を
06:06
about who they offer
these nuptial gifts to.
かなり慎重に選ぶということなんです
06:10
Now, the gift is very nutritious,
さてこのギフトは栄養豊富で
06:13
and the female eats it
during and after mating.
メスは交尾の最中からその後も
これを食べ続けます
06:15
So, the bigger it is,
the better off the male is,
つまり婚姻ギフトが大きいほど
オスに有利で
06:17
because that means more time for his sperm
なぜならオスは精子を
06:20
to drain into her body
and fertilize her eggs.
メスの体内に注入する時間が稼げますからね
06:22
But it also means that the males
are very passive about mating,
でもこれはつまりオスが交尾に
とても受け身だということを意味します
06:25
whereas the females
are extremely aggressive and competitive,
一方メスは この栄養豊富な婚姻ギフトを
06:29
in an attempt to get as many of these
nutritious nuptial gifts as they can.
出来るだけ多くとろうと
交尾に極めて積極的です
06:33
So, it's not exactly
a stereotypical set of rules.
だからこれは典型的な
性別による役割分担ではありません
06:37
Even more generally though,
より視野を広げてみるとさらに
06:42
males are actually not all that important
in the lives of a lot of insects.
多くの昆虫の生活において
実はオスは そこまで重要ではありません
06:44
In the social insects --
the bees and wasps and ants --
ハチ、スズメバチ、アリなどの
社会的昆虫の中には
06:49
the individuals that you see every day --
私達が日頃目にする個体
06:54
the ants going back and forth
to your sugar bowl,
砂糖壺の周りを行き来するアリや
06:56
the honey bees that are flitting
from flower to flower --
花から花へ飛び回ってるミツバチ
06:59
all of those are always female.
これらは全てメスです
07:02
People have had a hard time getting
their head around that idea for millennia.
この発想に至るまでには
実に何千年もの月日がかかりました
07:05
The ancient Greeks knew that there was
a class of bees, the drones,
古代ギリシャ人はすでに
働きバチよりも大きな「ドローン」という
07:09
that are larger than the workers,
階級の存在に気づいていたのですが
07:15
although they disapproved
of the drones' laziness
「ドローン」の怠け癖には
納得いかなかったようです
07:17
because they could see that
the drones just hang around the hive
なぜなら「ドローン」は
交尾の時期が来るまで
07:19
until the mating flight --
ただ巣の周りをうろうろして
07:22
they're the males.
何もしないからです
07:24
They hang around until the mating flight,
交尾の時期以外は
巣の周りをうろうろするだけで
07:25
but they don't participate
in gathering nectar or pollen.
蜜や花粉の収集に参加しないので
07:27
The Greeks couldn't figure out
the drones' sex,
ギリシャ人たちは「ドローン」が
オスだと分からなかったのです
07:30
and part of the confusion was that they
were aware of the stinging ability of bees
また 混乱の一因には
働きバチの刺す能力を知っていたため
07:32
but they found it difficult to believe
刺すような武器を
携えているのがメスだなんて
07:37
that any animals that bore such a weapon
could possibly be a female.
信じ難かったこともあります
07:40
Aristotle tried to get involved as well.
アリストテレスもまた
この議論に加担しようと試みました
07:43
He suggested, "OK, if the stinging
individuals are going to be the males ..."
「オーケイ 刺す個体はオスだよな」
とした途端
07:46
Then he got confused,
because that would have meant
彼は困りました
なぜならその考えで行くと
07:51
the males were also taking care
of the young in a colony,
オスがコロニーの中で
子育てをしていた事になり
07:53
and he seemed to think
that would be completely impossible.
彼はそれは完全にあり得ない
と考えたようでした
07:56
He then concluded that maybe
bees had the organs of both sexes
多分 ハチは雌雄同体なのだと
08:01
in the same individual,
結論したのです
08:04
which is not that far-fetched,
some animals do that,
そういう動物はいますから
これはありえるんです
08:05
but he never really
did get it figured out.
でも結局彼も
真実を見出すことはなかった
08:07
And you know, even today,
my students, for instance,
現代においても
例えば私の学生たちですら
08:10
call every animal they see,
including insects, a male.
目にする全ての動物を
昆虫も含めてオスと呼ぶんです
08:14
And when I tell them
that the ferocious army-ant soldiers
例えば 巨大な顎を使って
コロニーを守る
08:19
with their giant jaws,
used to defend the colony,
獰猛な兵隊アリは 皆メスなんだと
08:23
are all always female,
学生に説明しても
08:26
they seem to not quite believe me.
今ひとつ信じてくれない
08:29
(Laughter)
(笑)
08:31
And certainly all of the movies --
Antz, Bee Movie --
確かに 映画 『アンツ』や
『ビー・ムービー』では大抵
08:32
portray the main character
in the social insects as being male.
社会的昆虫の主役は
オスとして描かれます
08:37
Well, what difference does this make?
でもまあ大したことない
08:44
These are movies. They're fiction.
映画は作り話です
08:46
They have talking animals in them.
話す動物まで出てくるのに
08:48
What difference does it make
if they talk like Jerry Seinfeld?
ジェリー・サインフェルドっぽくって
何が悪いの?
08:50
I think it does matter,
私はそうは思いません
08:53
and it's a problem that actually
is part of a much deeper one
この問題はもっと
根深い問題の一部であり
08:55
that has implications
for medicine and health
医学や健康やその他の
私達の生活の側面に
08:58
and a lot of other aspects of our lives.
影響を及ぼす問題です
09:02
You all know that scientists
use what we call model systems,
ご存知のように科学者は
モデルシステムと呼ばれる手法により
09:05
which are creatures --
white rats or fruit flies --
ラットやショウジョウバエ等の生物を
09:09
that are kind of stand-ins
for all other animals, including people.
ヒトを含む全ての動物の
代役として実験に使います
09:12
And the idea is
that what's true for a person
これは
ヒトに起こることは
09:17
will also be true for the white rat.
ラットにも起こるという
発想です
09:20
And by and large,
that turns out to be the case.
この発想は概して正しいですが
09:22
But you can take the idea
of a model system too far.
このモデルシステムの発想が
度を越してしまうこともあります
09:25
And what I think we've done,
私が思うに
科学者がやってきたことは
09:29
is use males, in any species,
as though they are the model system.
実験で 全ての種でオスを
モデルケースに使うことでした
09:32
The norm.
それが普通
09:37
The way things are supposed to be.
そうあるべきだと
09:38
And females as a kind of variant --
そしてメスは例外
09:41
something special that you only study
after you get the basics down.
つまり特殊な事例として 基礎的知見ができた後にしか扱わない
09:44
And so, back to the insects.
昆虫に話を戻すと
09:49
I think what that means
思うにそれが意味するのは
09:52
is that people just couldn't see
what was in front of them.
人間には目の前のものを
あるがままには見られないという事
09:53
Because they assumed that the world's
stage was largely occupied by male players
なぜなら世界の舞台のほとんどが
オスで占められていて
09:56
and females would only have
minor, walk-on roles.
メスには目立たない脇役しか回ってこない
という思い込みがあるからです
10:03
But when we do that, we really miss out
on a lot of what nature is like.
でもそう思い込んだ途端 私たちは
自然のあり方の多くを見落とすことになります
10:07
And we can also miss out on the way
natural, living things, including people,
また そうするうちに 人間を含めた
自然や生物が持ち得る多様性の有様を
10:13
can vary.
見落とすことになります
10:20
And I think that's why we've used males
as models in a lot of medical research,
このため 多くの医学研究で
男性をモデルとして使ってきて
10:22
something that we know now to be a problem
その結果を男女両方に適用しようとすると
10:27
if we want the results to apply
to both men and women.
うまくいかないことに気づくのです
10:29
Well, the last thing
I really love about insects
私が虫を好きな最後の理由は
10:34
is something that a lot of people
find unnerving about them.
多くの人々にとってもビックリする事ですが
10:37
They have little, tiny brains
彼らの脳がわずかで 小さく
10:40
with very little cognitive ability,
the way we normally think of it.
私達が思っている以上に
認知能力はとても低いことです
10:42
They have complicated behavior,
but they lack complicated brains.
彼らの振る舞いは複雑ですが
彼らに複雑な脳はありません
10:46
And so, we can't just think of them
as though they're little people
だから私達は 昆虫を単に
小さな人間として考えてはいけない
10:51
because they don't do things
the way that we do.
なぜなら昆虫と人間のやり方は違うからです
10:57
I really love that it's difficult
to anthropomorphize insects,
その擬人化しにくさこそ
私が昆虫を好きな理由です
11:00
to look at them and just think of them
like they're little people
彼らを見て 小さな人間みたいに
とらえようとしても
11:04
in exoskeletons, with six legs.
外骨格をまとって 脚が6本あってはね
11:08
(Laughter)
(笑)
11:10
Instead, you really have to accept them
on their own terms,
そうではなく 彼ら独自のあり方を
受け入れる必要があります
11:12
because insects make us question
what's normal and what's natural.
何が普通で何が自然なのか
昆虫は問いかけてくれるからです
11:15
Now, you know, people write fiction
and talk about parallel universes.
さて 人々は架空の物語を書き
パラレル・ワールドについて語ります
11:21
They speculate about the supernatural,
超自然的な事物に思索を巡らせて
11:26
maybe the spirits of the departed
walking among us.
私達の間を死者の魂が歩いているかも
などと考えたりします
11:29
The allure of another world
異世界に対して憧れるのは
11:34
is something that people say is part of
why they want to dabble in the paranormal.
超常現象の世界に関わりたいからだ
と言われています
11:37
But as far as I'm concerned,
でも私は思うんです
11:44
who needs to be able to see dead people,
死者に会う能力なんて
必要でしょうか?
11:46
when you can see live insects?
生きた昆虫がそばにいるのに?
11:48
Thank you.
ありがとうございました
11:51
(Applause)
(拍手)
11:52
Translated by Maki Hasumi
Reviewed by Hiroko Kawano

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About the Speaker:

Marlene Zuk - Evolutionary biologist
Marlene Zuk studies insect behavior -- and how humans use animal behavior to think about how we behave ourselves.

Why you should listen

Marlene Zuk is a biologist and writer who researches animal behavior and evolution, mostly using insects as subjects. Zuk is interested in the ways that people use animal behavior to think about human behavior, and vice versa, as well as in the public's understanding of evolution. She teaches graduate and undergraduate courses in the Department of Ecology, Evolution and Behavior at the University of Minnesota -- including a seminar called “What’s the Alternative to Alternative Medicine?”

In addition to publishing numerous scientific articles, Zuk has published four books for a general audience: Sexual Selections: What We Can and Can’t Learn About Sex from AnimalsRiddled with Life: Friendly Worms, Ladybug Sex, and the Parasites That Make Us Who We AreSex on Six Legs: Lessons on Life, Love and Language from the Insect World; and most recently, Paleofantasy: What Evolution Really Tells Us About Sex, Diet and the Way We Live.

More profile about the speaker
Marlene Zuk | Speaker | TED.com