Every autumn, millions of monarch butterflies have taken off from diverse points in the U.S. and Canada and flown thousands of miles to converge on a place they’ve never seen before – a forest west of Mexico City. With brains the size of pinheads and bodies easily buffeted by the wind, these insects carry out the navigational feat with internal clocks and compasses scientists have just begun to understand.
A few years ago, scientists sounded the alarm that illegal logging in those Mexican forests threatened to destroy the migration pattern forever. And now, according to a new report by U.S. and Mexican environmental groups, the Mexicans have done their part to crack down on logging, but human activity in the U.S. is causing a precipitous decline in migrating butterflies.
The news stories that followed say the report cites multiple causes, including the loss of the milkweed on which the butterflies depend as it’s replaced with rows of corn. The milkweed no longer grows between the rows of corn, according to the report, because farmers are planting herbicide-resistant GMO corn and then dousing the fields with milkweed-killing herbicides.
The New York Times, Washington Post, AP, and National Geographic Online ran with similar stories, straightforwardly summarizing the report and in some cases, covering a related press conference that took place in Mexico.
At Science, Lizzie Wade went a step further in her story, with an outside source who warns that while the end of the migration behavior wouldn’t cause monarchs to go extinct, the non-migrating survivors would be vulnerable to disease:
Staying in one place for many generations makes the butterflies more susceptible to the deadly Ophryocystis elektroscirrha parasite. According to Lincoln Brower, a biologist at Sweet Briar College in Virginia, the “insidious disease” spreads when infected butterflies scatter spores on milkweed plants, which are then ingested by the next generation of caterpillars. If fewer butterflies migrate to Mexico, he says, the proportion of infected monarchs across North America may increase, imperiling the whole population.
Slate ran with the most enterprising story, by Warren Cornwall, who turned the focus to the role of Monstanto's roundup herbicide and roundup-ready GMO corn:
In 2013, 83 percent of all corn and 93 percent of soybeans in the United States were herbicide tolerant, totaling nearly 155 million acres, much of it in the Midwest.
It’s no coincidence monarchs faltered at the same time. Karen Oberhauser, a conservation biologist at the University of Minnesota, and a colleague estimated that as Monsanto’s Roundup Ready corn and soybeans spread across the Midwest, the amount of milkweed in farm fields fell by more than 80 percent. Oberhauser determined that the loss of milkweed almost exactly mirrored the decline in monarch egg production.
The author include an important part of the story others missed: A 2012 study playing down the role of herbicides and the reaction by scientists who disputed it:
Monsanto emphasizes that loss of milkweed to herbicides isn’t the only culprit. Tom Helscher, Monsanto’s director of corporate affairs, notes that a 2012 study found monarch numbers hadn’t fallen at sites in New Jersey and northern Michigan. (Taylor and other monarch scientists dismiss the study because it looked at populations where milkweed is still relatively abundant.) And, Helscher said, butterfly conservation needs to be balanced with “society’s need to improve productivity in agriculture.”
Unfortunately, when I tried to follow the links I got an error message, which was frustrating considering how important this paragraph is to the point of the story.
But this is a quibble since no-one else even brought up the 2012 paper and the reaction. The other thing that’s folded into this graph is a Monsanto viewpoint. Here, it helps make the story more compelling by allowing the author to focus on the cause of the problem. So instead of leaving readers feeling like passive witnesses to a tragedy, we’re left feeling complicit, but with choices.
Including the company spokesman forces us to confront the possibility that the blame does not begin and end with executives at Monsanto. The company is filling an American demand for cheap fuel and cheap hamburgers. Readers can decide whether these commodities represent a “need” as the Monsanto rep calls it, or whether it’s a desire that we could curtail as we become more aware of profound and sometimes irreversible costs.
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