Biologists want Wyomingites to report monarch butterfly sightings

Every year thousands of monarch butterflies migrate from the warmth of southern Mexico where they winter, all the way to Canada, laying eggs along the route. Some butterflies will travel more than 3,000 miles.  

The butterflies are losing their wintering grounds to deforestation, said Lusha Tronstad, invertebrate zoologist with the Wyoming Natural Diversity Database. Urbanization and insecticides take away the milkweed where the butterflies lay eggs and caterpillars feed. In 2014 the U.S. Fish and Wildlife Service received a petition to put monarch butterflies on the endangered species list. The agency says more data is needed on the invertebrates to make a listing determination for the monarch, and several Wyoming groups are taking action to help.

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The Wyoming Natural Diversity Database, the Nature Conservancy and the University of Wyoming’s Biodiversity Institute started a citizen scientist project last year to find out how and when the butterflies rely on habitat in Wyoming.

“We know nothing about them, other than they are here,” Tronstad said. “We see the birds, the bears and the antelope, but we often don’t pay attention to the spineless creatures out there.”

The multi-year data collection effort relies on volunteers across the state. When people see a monarch, or milkweed, they report it online. In its pilot year, about a dozen volunteers reported a total 28 observations of monarchs in Laramie, Kemmerer, Lander, Cody, Cheyenne and Buffalo, said Brenna Marsicek, outreach coordinator at the University of Wyoming Biodiversity Institute. That first year proved butterflies use the state. People also reported finding eggs on milkweed plants, Marsicek said. That’s significant, but scientists still need more information about how much they reproduce in Wyoming.

Anyone can help by reporting their monarch observations on the groups’ website Monarchs & Milkweeds. The website lists how to identify the butterflies and report sightings. Organizers are especially interested in reports of milkweed. Several species found in Wyoming are rare.

Monarchs lay eggs on milkweed, and when the eggs hatch the caterpillars eat the plant, giving them a bitter taste that deters many predators. Wyoming has several species of milkweed, including five that are found in few other places, Marsicek said. Documenting where those plants are and if the butterflies are using them is important in understanding what habitat needs to be preserved to help monarchs survive their migration.

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Monarchs are important pollinators. They also are a food source for birds and other species. They seem small, but their survival is crucial to healthy ecosystems from Mexico to Canada.

Tronstad said the data collection effort is a perfect opportunity to include citizen scientists. Theoretically the butterflies flew throughout the state so it was important to have at least one data site in every county. That would have been too expensive and large an effort without recruiting volunteers.

Monarchs are also easy to identify with their bright orange coloring. They have only one mimic, the viceroy, which has a straight line across its back wing, unlike the uneven markings on a monarch. Most people can tell the difference between the two species once they know what to look for.

Plus, if ever there was an invertebrate people would get excited about helping, it’s a butterfly.

“Monarchs are a charismatic microfauna,” Tronstad said. “Everyone knows what a monarch is. They are carrying the flag for all invertebrates.”