Give Now  »

Indiana Public Media | WFIU - NPR | WTIU - PBS

Study: Monarch Butterflies Could Be Extinct In Two Decades

Monarch on milkweed

Right now, millions of monarch butterflies are making their way back to the U.S. after a warm winter in Mexico.

But 20 years from now, there may be no monarch butterflies left to migrate.

That's according to new research by the Scripps Institution of Oceanography and the U.S. Geological Survey. Published March 21 in Scientific Reports, the study says the migratory population of Danaus plexippus (the eastern Monarch butterfly) has declined by around 80 percent in the past decade, and has a significant chance of quasi-extinction -- population numbers so low they can't recover -- in the next two decades.

"Recovery for the population really depends on the amount of breeding habitat," said Scripps Institution of Oceanography researcher Brice Semmens to KPBS. "And breeding habitat means the amount of milkweed that's available for reproduction. Monarchs rely exclusively on milkweed to reproduce."

Adult monarchs lay eggs on milkweed plants, on which monarch larvae exclusively feed and live. But milkweed is also quietly creeping toward extinction, thanks in large part to herbicides and the implementation of genetically modified glyphosate-tolerant corn and soybeans.

One 2012 study says there has been a 58 percent decline in milkweed in the Midwest from 1999 to 2010, correlating with an 81 percent decline in monarch production during the same time frame.

So what's the answer? The good news is that people are already paying attention to the plight of the monarchs. The U.S. Fish and Wildlife service last year announced plans to build a "butterfly highway" lined with milkweed and other habitat plants, and the conversation organization Monarch Watch laid out a 2014 recovery plan for the charismatic species.

The Scripps Institution researchers say the number of monarch butterflies must increase five-fold to reduce the risk of extinction by half.

Read More:



  • Quasi-extinction risk and population targets for the Eastern, migratory population of monarch butterflies (Nature)
  • The monarch massacre: Nearly a billion butterflies have vanished (Washington Post)
  • Monarch Butterfly Recovery Plan (Monarch Watch)


Support For Indiana Public Media Comes From

About Earth Eats

Harvest Public Media