Monarch butterfly

Most monarch butterflies spend the winter in Mexico. But the rest of the year they can be found throughout much of the continental U.S. – as long as there’s milkweed. This tall plant is the only food monarch caterpillars eat, so that’s where the butterflies lay their eggs.

But Chip Taylor of the University of Kansas Monarch Watch says human development and agricultural practices, including herbicide use, have eliminated a lot of milkweed.

That’s making it harder for monarchs to find stop-over sites where they can lay their eggs during their summer migration.

Now, global warming is adding more pressure on a species that’s already stressed. For example, when spring comes early in Texas, the monarchs might head north before milkweed has developed enough to lay their eggs.

Taylor: “Ten of the last twenty years, March temperatures in Texas have been substantially above average. Almost every year that those temperatures go up in Texas, we see the population decline.”

'If we don't slow #CO2 down, it's game over for monarchs. It really will be game over.' Click To Tweet

So, the long-term survival of monarchs depends on a big effort to plant milkweed and reduce global warming.

Taylor: “If we don’t slow CO2 down, it’s game over for monarchs. It really will be game over.”

Reporting credit: ChavoBart Digital Media.

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