Listener supported WNYC Studios.

This is Science Friday.

I'm Flora Lichten.

Today in the podcast, a sweeping study of a beloved insect.

Because people love butterflies, we're able to get a more complete

picture about what's going on with butterflies compared to many, many other insect groups.

You've heard about monarch declines, but new research in the journal science widens the butterfly

net and checks in on over 500 species. And the researchers found

that many populations are taking a nosedive. So what's causing the downswing? And is there anything to do?

Joining me now to explain are two of the study authors. Elise Zipkin is the Red Cedar

Distinguished Professor of Quantitative Ecology and Director of the Ecology Evolution and Behavior Program at Michigan State University.

And Nick Haddad is a professor of Integrative Biology also at Michigan State University in East Lansing, Michigan.

Welcome to you both to Science Friday.

Thanks for having us.

Okay, top level, what did you find?

So we aggregated all the data that were available across the United States, which was

35 different monitoring programs that collect information about butterflies. And we put that into a general model to look at how are

butterflies doing overall and which species are doing better and worse. And what we found in our

big grand model was that 22% of individuals had declined since the year 2000.

So what that means is if there were five individual butterflies in the year 2000,

there were only four in the year 2020.

We also found that there was about 13 times more species declining than increasing.

...