木曜日は、マリーのはてな日記/Marie the Scientist
Will insect spray make cockroaches stronger?」
Will insect spray make cockroaches stronger?
Today, my mother was screaming in the kitchen.
There was a big cockroach.
Use this insect spray.
I don’t want that cockroach to come my way.”
“Mom, I don’t know which way it’s going to run.”
“No, not this way!”
The cockroach rolled over and died.
I was glad that I won against the cockroach.
But a question came into my mind.
If I keep using the insect spray to kill cockroaches, will they become stronger or maybe not die anymore?
So I decided to ask my cousin, Shinichi.
He loves insects.
I know you study insects at your university.
Can you tell me something about them?”
“Will insect spray make cockroaches stronger?”
“Oh, why do you think that?”
“I know all living things change to become better and stronger to stay alive.
I read in a book that cockroaches have been on the earth longer than humans.
The book said when the environment changed, they changed, too.
So I thought using insect spray might make cockroaches change and become stronger.”
“I love the way you think, Marie.
When a living thing finds a new way to live, it’s called evolution.”
“So let’s say that you use insect spray on 100 cockroaches.
It kills 99 of them but doesn’t work on 1 cockroach.
That cockroach continues to live then passes its DNA to its children, grandchildren, and so on.
In this way, the number of strong cockroaches grows and grows.”
“The cockroaches evolved.
I knew it.”
“This is also a process called coevolution.”
“Another new word.”
“If two living things make each other stronger, that is called coevolution.
It’s like a war between humans and cockroaches.
Humans want to kill cockroaches so we evolved to make a weapon called insect spray.
But cockroaches don’t want to die.
So they may evolve to become stronger against insect spray.
If both humans and cockroaches get stronger, that’s coevolution.”
“Ah, I think I understand.”
“But Marie, evolution happens over a very long time.”
“Hundreds of millions of years, so we will never know if cockroaches become stronger than an insect spray.”
“Wow, so humans and cockroaches will keep fighting for a long time.”
We are learning from them, too.
Right now, people are studying how cockroaches move.
Did you know cockroaches can change the size of their bodies while moving very quickly?”
“No, that’s amazing!”
Scientists are trying to make a robot to copy their movements.”
I learned so much today.
My mom was also glad to know cockroaches are helping us.