Story by Marsha Walton
Talk about endurance athletes! Monarch butterflies make human tri-athletes look like slackers. Millions of these beautiful insects (weighing less than two ounces as adults) embark on a spectacular 2000+-mile journey from the United States and Canada to spend winters on a few mountaintops in central Mexico.
Tens of millions of the orange and black butterflies create one of the most stunning sights in the natural world, during their winter slumber party in the oyamel trees in the state of Michoacán.
While there is no clear evidence of a population decline in monarchs (Danaus plexippus) across this continent, scientists are concerned about threats to their habitat and other human-induced pressures.
“The mountaintops where they overwinter are the Achilles heel of North American monarchs,” said Andy Davis, a monarch expert and doctoral student at the Warnell School of Forestry and Natural Resources at the University of Georgia. “If they go, the whole system may collapse,” he said.
A few weeks ago a “butterfly brain trust” from Canada, U.S. and Mexico met at the University of Georgia to discuss ways to improve monarch population monitoring programs.
Davis and Professor Sonia Altizer of Georgia’s Odum School of Ecology organized the gathering, designed to get the three governments on the same track for monarch observation and protection.
For nearly 30 years scientists have been collecting data on monarchs. This new effort aims to coordinate that information among governments, universities, conservation groups, and another group of growing importance—citizen scientists.
“Citizen scientists are extremely important to large-scale monitoring programs, which, if run only by paid staff, could rarely, if ever, collect the amount of data that volunteers can over the broader landscape,” said biologist Tara Crewe of Bird Studies Canada.
Currently, information collected by individuals or even some conservation groups might be unknown to others with the same mission—to protect this elegant species and its habitat. The Commission for Environmental Cooperation, established by Canada, U.S., and Mexico, is a major player in the effort to improve data collection, and, scientists hope, better target research and conservation efforts for the monarch.
These butterflies face a lot of different threats, including the disappearance of habitat. Females must lay their eggs (usually 100-400) on the underside of milkweed leaves. A toxin in that plant protects the caterpillar and butterfly from predators.
“Unfortunately, milkweed is still considered a noxious weed in Ontario and some states, even though this plant is required for monarch larval development,” said Crewe. “There is also evidence that some farming practices reduce the amount of milkweed available to monarchs,” she said.
Monarchs must fly south for the winter. They cannot fly in temperatures below 55 degrees Fahrenheit. And while caterpillars feed exclusively on milkweed, adults need nectar from other flowers, so they have to go where the food is. In Mexico, it is habitat loss from logging that puts them in jeopardy.
Davis said protection and understanding of monarchs doesn’t take a lot of study. His advice to young people fascinated by these iconic butterflies: “Ask questions. Be curious. Get outside and start looking at plants and caterpillars. Ask yourself, ‘Why is it there? Why this plant, and not that one? Why is there only one here, and six on another one?’”
Questions like that, he said, are the basis of all good science, and could spark an interest in contributing important data to monarch research.
Crewe suggested participation in monitoring programs already in place, including Journey North, Monarch Larvae Monitoring Program, Monarch Health, and Monarch Watch. MonarchNet.org is now in development, and will provide links to many programs.
“People can also plant butterfly gardens at their home or school, with a focus on milkweed and other flowering plants (for nectar) that are native to their area,” said Crewe. “Native plants are preferred because they are adapted to the climate and require less maintenance and watering than non-native species,” she said.
“Native flowering species are a great deal of help,” said Davis. “[The monarchs] migrate through the Appalachians,” he said. Migration south takes place from August until mid-November.
While pandas and polar bears may be the most visible stars of the conservation world, Crewe believes the monarch is also a great ambassador species.
“People are overall very fascinated by the life cycle of this insect,” said Crewe. “The fact that monarchs that developed in northeastern North America can fly all the way to Mexico, without ‘parents’ to show them the way, is astounding! Its long-distance migration is truly unique to the insect world, and that alone is reason to conserve this species and this phenomenon in particular,” she said.