Disappearance of Monarch Butterflies Linked to Deforestation and GMO Crops

Posted Sept. 3, 2014

MP3 Interview with Susan Hanley, manager of the Native Species Butterfly House at the Paul Smith's College Visitor Interpretive Center, conducted by Melinda Tuhus


Late summer is the season when monarch butterflies begin their migration from the Northeast and Midwest of the United States to their wintering grounds in the Oyamel fir forest of Mexico. But this year the monarchs are in crisis. Many observers report seeing very few or no monarchs at all during the summer months this year, when in the recent past they were common all over the eastern half of the U.S. In fact researchers have found that over the last two decades the monarch butterfly population has declined by 90 percent in the eastern U.S. Scientists say there are several reasons for the monarch’s population crash that include: deforestation of the insects breeding areas in Mexico, the negative effects of GMO crops and the destruction of milkweed, the plant where monarch’s exclusively lay their eggs.

Fortunately, there are ways to help these iconic creatures survive. Three major conservation groups have called on the U.S. Fish and Wildlife Service to designate the monarch as a threatened species, an action that would give federal officials the power to launch new initiatives to protect their habitat.

Between The Lines’ Melinda Tuhus spoke with Sue Hanley, Native Species Butterfly House manager at the Paul Smiths Visitors Interpretive Center in the Adirondack Mountains in upstate New York. She explains that the monarchs we see now are the great-grandchildren of the ones who were last seen in the Northeast and Midwest, as it takes four generations for them to make the round-trip journey from Mexico. She describes the threats facing the monarchs as well as individual and organizational responses to those challenges.

SUSAN HANLEY: The monarch originated in South America and followed milkweed north through Mexico and North America. So there is a population in Florida that by and large does not migrate; they just shift north and south within Florida. And there is a western migration, west of the Rockies, that goes to the coast of California and down into Baja to over-winter. But the eastern migration was, of course, always the largest, being the Northeast and the Midwest and all funneling down into Mexico, and that's the migration that's been so hard hit. There are too many things going wrong for the monarchs, and unfortunately they are all pretty much based on human behavior. It's a combination of deforestation in Mexico for their over-wintering spot; GMO corn which is Roundup-Ready so that you can spray indiscriminately – their milkweed gets sprayed so they don't have any, or the milkweed gets sprayed and it's poisonous to eat; roadside mowing ... there are so many things that we do that are harmful to monarchs and they just can't handle it anymore.

BETWEEN THE LINES: It's interesting that the monarch lays its eggs only on milkweed plants and the monarch caterpillars that hatch out eat only milkweed. That seems like it might hinder their survival.

SUSAN HANLEY: Most butterflies and moths are specific to a plant that they want as their host plant for their caterpillars and they will only lay their eggs on the plant that they want, and monarchs have chosen milkweed because that white sap in the milkweed has cardiac glycosides; it makes their predators very ill. Predators with a spine and a nervous system feel nausea or vomiting when they eat a monarch, so they learn not to eat a monarch and they teach their offspring not to eat a monarch. So, it was a very good choice on the monarch's part. The only predators the monarch has are other insects; they are not affected by the toxin. But unfortunately, milkweed is something that's considered a noxious weed to farmers here in the States. It has just been de-listed in Canada as being a noxious weed, so they are going to have an easier time conserving their milkweed than we are.

BETWEEN THE LINES: Why is it considered a noxious weed by humans?

SUSAN HANLEY: Anybody that grows cattle, any farmer who's raising cattle doesn't want their cattle to get sick by eating milkweed. Most ranges where cattle are eating don't have that much milkweed, actually.

BETWEEN THE LINES: Butterflies have this mythic reputation of representing freedom and beauty and playfulness – and, of course, that's value just in that. But do they serve a broader purpose besides being beautiful?

SUSAN HANLEY: Yes, besides being beautiful, butterflies have a dual purpose. They are pollinators – not always as efficient as bees, but they are very good pollinators, and they are also a huge food source for birds, bats, rodents, frogs and snakes. Of course, now there are not as many of them to be a food source for those animals, so they are jeopardizing other animals, too.

BETWEEN THE LINES: If Round-Up is such a huge contributor to the fall-off in the monarch population, is there anything being done to pressure Monsanto, the producer of Round-Up, to do something about this terrible problem?

SUSAN HANLEY: One of the agencies leading the charge now is Friends of the Earth, and they have a special branch, Bee Action, beeaction.org, because the bees are in trouble for similar reasons that the monarchs are in trouble. And yes, (Friends of the Earth) are doing a lot of citizen science actions and legislative actions and they are doing a great job. But because Monsanto is so powerful and has so much money, the Monarch Watch folks have decided that as a community we who care about monarchs need to be planting organic way station gardens and doing everything we can to feed them and care for them because we can't exactly wait until somebody is able to get through to Monsanto – it may not happen. People are very concerned and wanting to help because the monarch is a beloved butterfly. People are mostly saying I'm used to seeing lots of them and I don't anymore. Why? And when they find out that human beings are why, they want to make amends. They want to do something. And there's so much you can do. Even if you're already growing milkweed, you can plant bright nectar flowers, so that the overflying monarchs will see your milkweed – they'll see the bright flower and come use your milkweed. If you're doing that and you notice eggs on your plant, why not go to the hardware store and get some paint strainers and put them over the plants and make sure those caterpillars go to maturity and become monarchs. Then if you have kids in school whose class should hear about this or if you want to go to a Scout troop meeting and let those people know. Scouts are some of the best kids for getting out and planting things, and if you want them to be planting milkweed you can give them an inspirational talk.

For more information on the Native Species Butterfly House at the Paul Smith's College Visitor Interpretive Center in New York state, visit http://www.adirondackvic.org/Butterfly%20House.html.

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