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monarch butterfly

Timothy Bargar / USGS

Monarch butterflies need more to eat. That's the conclusion of a new study from the U.S. Geological Survey.

The only thing monarch butterfly caterpillars can eat is milkweed.

Wayne Thogmartin is a quantitative ecologist with the USGS. He says the butterfly population has dropped by about 80% since the mid-90s. The population has rebounded a little bit in the last three years, but Thogmartin says it's not a huge improvement.

Studies show the Eastern Monarch Butterfly population has decreased by as much as 80% in the last decade.
flickr user Paul VanDerWerf / http://michrad.io/1LXrdJM

Scientists continue to keep a nervous eye on North America’s eastern monarch butterfly population.

That population has dropped by more than 80% over the past decade.

A study published this week in the journal Scientific Reports suggests there’s a “substantial chance” that monarchs could become “quasi-extinct” within the next 20 years.

photo of a monarch butterfly
user Jim, the Photographer / Flickr - http://michrad.io/1LXrdJM

This week, two environmental groups, the Center for Biological Diversity and the Center for Food Safety, put the U.S. Fish and Wildlife Service on notice.

They’re planning to sue the agency because they say it’s dragging its feet on protecting the monarch butterfly.

Monarch caterpillars can die if they are exposed to milkweed that has been treated with neonicitinoids, a type of insecticide.
Monarch Watch

Monarch butterflies need milkweed to survive, but some plants you buy for your garden could be toxic to them.

There’s been a big drop in the monarch butterfly population. By some estimates, they’ve declined by more than 90 percent over the past 20 years.

Monarch Watch

Monarch butterflies are not around in the numbers they used to be — not by a long shot. By some estimates, monarch populations have dropped by 90% over the past twenty years. 

But why has that happened to these iconic butterflies? 

Tiago J. G. Fernandes / Wikimedia Commons

Monarch butterflies are declining.

The U.S. Fish and Wildlife Service is considering whether to add the monarch butterfly as a threatened species under the Endangered Species Act. The agency just launched a one-year review of the butterfly’s status.