March 31, 2014 12:00 PM

Monarchs butterflies' migration is in peril because of rampant herbicide use

Every year, hundreds of millions of monarch butterflies find their way on what may be the world’s longest insect migration, traveling the length of North America to pass the winter in central Mexico. Yet the great monarch migration is in peril, a victim of rampant herbicide use. Over the past decade, U.S. fields containing milkweed have declined sharply. Orley “Chip” Taylor, a monarch expert at the University of Kansas, calls the loss “massive.”

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