Nell Greenfield Boyce

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...

Like aphids, they avoid red leaves.

So there was this one study where Marco looked at apple trees and found that those with red leaves had fewer aphids on them than the trees with green or yellow leaves.

That's wild.

He's got some evidence that aphids actually have a worse survival rate on red trees compared to aphids on yellow or green ones.

I mean, there has not been a huge amount of experimental work on this, but he told me if you ask him why some leaves go red.

True.

I mean, out west.

I mean, worldwide, it's a minority of trees that go red.

I was just talking to Nikki Hughes, and she told me there's just this dearth of research in general.

Like other than tourism, like what's the application here?

It's not like it's important for agriculture or something, you know.