Fifth-grade students stand around plastic containers at The College School of Webster Groves, captivated by a caterpillar wriggling as it sheds its skin for a fifth time and transforms into a chrysalis. “Gerald! Gerald!” one of the students exclaims, calling to teacher Gerald Axelbaum. “It’s shedding!” As part of the unit on monarch butterflies, Axelbaum and his students make annual fall field trips to Shaw Nature Reserve to catch butterflies, tag them, and release them to continue their southward journey.
Each year, the insects travel from as far north as Canada to a small strip of forest in the Sierra Madre of central Mexico, where they spend the winter before new generations make the return flight. Axelbaum has been teaching his students about the butterflies for two decades. Over that same period, scientists say, the monarch butterfly population has decreased by more than 80 percent. Part of the blame rests about 30 miles northeast of the nature reserve, at Monsanto, which produces the popular herbicide Roundup. It’s used to kill milkweed, which is essential for monarch survival but a nuisance to farmers.
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Now the St. Louis–based company has pledged to spend more than $3 million over the next several years on milkweed habitat restoration, education, and outreach. For example, Monsanto has provided funding to Monarch Watch, a Kansas-based organization that is offering 100,000 free milkweed plugs for large-scale restoration projects. The collaboration between Monsanto, a frequent target of criticism by organic farmers and environmentalists, and nonprofit organizations could determine the future of the monarch.
“Monarchs rely on milkweed as a place to lay their eggs and as a food source for larvae,” Monsanto states on its website. “But, milkweeds are among hundreds of weed species that farmers seek to control to prevent the weeds from competing for resources with crops. Weed management has been a contributing factor to the decline in milkweed habitat.” Monsanto’s focus is production agriculture, says Linda Dudenhoeffer, the company’s director of corporate strategy, “but we are also concerned about the ecosystems in which we operate, and we support the restoration efforts that are under way.”
The success of those efforts will affect Axelbaum’s class. His students used to tag 100 butterflies in a day; in September, they didn’t tag any. They also hold a teleconference with Monarch Watch founder and director Chip Taylor. He doesn’t criticize Monsanto or farmers. “If I were a farmer, I would be trying to intensify my production,” he says. “I have a family to feed.”
Taylor is optimistic that if various public, private, and nonprofit groups work together, the butterfly population will rebound. The amount of forest in Central Mexico covered by butterflies increased from 2.79 acres in 2014 to 10 acres this winter, according to the World Wildlife Fund. The report prompted a rush of positive headlines, but Taylor cautioned that the increase was largely due to annual variation in temperatures and that the numbers remained low.
Axelbaum hopes the butterflies return. When students run through the reserve with nets, “chasing after a monarch, trying to catch one, there’s no sight like that,” he says. The question is whether next year there will be any butterflies for them to catch.
Monarch Facts
• Each year, monarch butterflies migrate as far as 3,000 miles.
• The monarch butterfly that overwinters in Mexico is often four generations removed from the butterfly that spent the previous winter there. The insects that travel south have never done so before.
• Monarch caterpillars feed almost exclusively on milkweed; as adults, the insects get their nutrients from the nectar of flowers.
