Nell Greenfield Boyce

And he's been skeptical about this idea that red pigments are there to protect the tree from sunlight as it's trying to recover its nutrients and store them away.

He has this whole other idea about why some trees evolve to turn red.

And it basically boils down to protection from insects.

Oh, so the kind that lay eggs in autumn.

Why?

Why?

Well, basically, he thinks the red, you know, like in nature, red is often like a warning signal.

Right.

And so he thinks the red could basically be telling them, don't lay your eggs here.

Like, this is not a good place for you.

And when he published this idea years ago, it was really controversial.

OK, the plant physiologist didn't like it.

I mean, it's still kind of controversial.

I mean, he says you'd think the entomologists, the people who are into bugs, you'd think that they would have liked it.

Oh, most insects can't see red?

No.

And, you know, even among mammals, incidentally, we humans are really unusual in our ability to see red.

There's even this theory out there that we evolved, along with certain primates, that we evolved to see red to see insects.

Experiments have shown that even if insects can't see red, just like we do, they can still distinguish between different leaf colors, like green, red, and yellow.

And it turns out...