Monsanto blamed for disappearance of monarch butterflies

As scientists continue to track the shrinking population of the North American monarch butterfly, one researcher thinks she has found a big reason it’s in danger: Monsanto’s Roundup herbicide.

On Wednesday, the World Wildlife Fund announced that last year’s migration – from Canada and the United States down to Mexico – was the lowest it’s been since scientists began tracking it in 1993. In November, the butterflies could be found on a mere 1.6 acres of forest near Mexico’s Monarch Butterfly Biosphere Reserve, a decline of more than 43 percent over the previous year.

Back in 1996, the insects could be found covering a span of 45 acres. Part of the decline can be attributed to illegal logging in Mexico that has decimated the butterfly’s natural habitat, as well as rising temperatures, which threaten to dry out monarch eggs and prevent them from hatching.

Now, though, biologist Karen Oberhauser of the University of Minnesota has also pinpointed the increased use of Monsanto’s Roundup herbicides in the United States and Canada as a culprit.

According to Oberhauser, the use of Roundup has destroyed the monarch butterfly’s primary food source, a weed called milkweed that used to be commonly found across North America. As the agriculture industry boomed and farmers effectively eliminated the weed from the land in order to maximize crop growth, she was able to catalog a parallel decline in the butterfly’s population.

Speaking with Slate, Oberhauser said that when the milkweed population across the Midwest shrank by 80 percent, the monarch butterfly population decreased by the same amount. With some states such as Iowa losing more than 98 percent of their milkweed population – the weed doesn’t even grow on the edges of farmland anymore – the disappearance of the plant poses a huge risk to the insect’s survival.

“We have this smoking gun,” she told Slate. “This is the only thing that we’ve actually been able to correlate with decreasing monarch numbers.”

For its part, Monsanto noted that herbicides aren't the only reason the monarch is dying. The company cited studies that showed the butterfly’s population in Michigan and New Jersey were not shrinking, though scientists have dismissed those studies since they focused on areas where milkweed was still prevalent.

Monsanto has come under fire before for the effects of its agriculture-oriented chemicals. As RT reported last year, studies linked Roundup’s main ingredient to diseases such as cancer, autism and Alzheimer’s. In spite of these findings, the Environmental Protection Agency ruled to raise the permissible level of the ingredient that can be found on crops.

Meanwhile, another report in October found a clear link between the pesticides sold by Monsanto in Argentina and a range of maladies, including higher risk of cancer and thyroid problems, as well as birth defects.

As for the plight of the monarch butterfly, the insect is still thriving in Hawaii and countries like Australia and New Zealand. In North America, Oberhauser believes the great migration can still rebound due to the monarch’s high fertility rates (a single female can lay up to 1,000 eggs throughout her life). For that to happen, however, scientists believe the US, Canada and Mexico will have to work together and draft a strategy that will help the insect safely make its way through the three countries.

“I think it’s past time for Canada and the United States to enact measures to protect the breeding range of the monarchs,” monarch expert Phil Schappert of Nova Scotia told the Washington Post, “or I fear the spiral of decline will continue.”