Welcome to my zone 9a habitat garden near Houston, Texas.

Tuesday, July 12, 2011

Will genetically modified crops be the death of the Monarch butterfly?

I came across a very worrying article in the science section of The New York Times this week.  It was about the effect upon Monarch butterflies of genetically modified crops grown in the Midwest.   Some scientists think it may be the final nail in the beautiful butterfly's coffin.

I admit I haven't followed the debate over genetically modified crops all that closely, but in reading this story I learned that, according to the Department of Agriculture, 94 percent of soybeans and 72 percent of corn being grown in the United States today are genetically modified to be herbicide-tolerant. Roundup won't hurt them.  Farmers can spray as much Roundup or its generic form, glyphosate, as they want on their crops to control weeds and it will not harm their soybeans or corn.

But, as it happens, one of the most widespread weeds across the entire area of the Midwest where corn and soybeans are grown is milkweed, the butterfly weed that Monarch and Queen butterflies depend upon for their reproduction.  At least it used to be one of the most widespread weeds.  Now that Roundup is liberally sprayed all over the area, it has virtually disappeared with the result that many migrating Monarchs find no safe place to lay their eggs.

A group of scientists has completed a study of the herbicide's effect on the butterfly population and they've recently published their paper online in the journal Insect Conservation and Diversity.  Lincoln Brower, an entomologist at Sweet Briar College, who has done studies of the decline of Monarch populations on their wintering grounds in Mexico, is quoted in the Times article as saying about Roundup/glyphosate, "It kills everything. It is like absolute Armageddon for biodiversity over a huge area."

There are many factors that are conspiring against the continued existence of the Monarch.  The increasing prevalence of extreme weather conditions in Mexico in winter as well as extremes of weather on their migration routes; urban development across North America that has removed much of the butterfly weed that they formerly depended upon; the widespread use of pesticides and herbicides in suburban and urban gardens; and now this.  They are such fragile creatures.  How much more can they stand?

And we might well consider Mr. Brower's statement about the herbicide killing everything.  There are other "weeds" in the habitat that are depended on by other creatures.  The herbicides kill them, too, and in so doing may doom the other creatures that utilize them.

It is clear to me that the chemicals used in modern farming and, all too often, in suburban gardens are a very mixed bag.  Certainly they do make the farmer's difficult job of weeding his crops easier, but at what cost?  And do we really want to pay that price?   DDT was a very effective chemical, too.  It did destroy populations of mosquitoes.  It also almost got rid of the Bald Eagle, the Osprey, the Peregrine Falcon, and the Brown Pelican, to name just a few of the affected species.

Is there anything that we as individual gardeners can do to help the Monarch?  We can pay attention to the debate about genetically modified crops and make our views known to our elected representatives.  Just be aware that Monsanto and other chemical companies are also busy making their views known to those same representatives, and they are throwing millions of dollars at them to make sure that their voices are heard.

Beyond that, we can do as the organization Monarch Watch suggests and plant more butterfly weed in our own yards, and, of course, refrain from using any of those chemicals that may be detrimental to butterflies.  I've done all that and yet I've seen very few Monarchs in my garden all year and none since the middle of spring.  Something is happening here.  What it is may not be exactly clear, but I don't think it's good news for the Monarch.  


  1. Kathleen Scott shared your blog link with me, and I am glad she did. I agree with your concerns about the butterflies -- had not been aware of this. Now that you mention it, I haven't noticed as many Monarchs as I did when I was a kid. (I live in suburban Detroit). Worrisome.

  2. I'm delighted you stopped by, Cindy L. There are so many challenges to the survival of these wonderful insects - pollution, development, herbicides, pesticides, climate change - one wonders how they can possibly continue in such a hostile world. As gardeners, we just have to do what we can to help them by providing the habitats they need.