Travels & Trails 52 Health

Magnificent Monarchs of Mexico

by Ron Miller, M.S., Silviculturist

Monarch (Danaus plexipus)

The race is on! Millions of monarch butterflies that some friends and I were fortunate to see in the Sierra Madre mountains of Michoacan, Mexico have headed north. Texas, almost certainly, has already been blessed with their presence and the next generation of monarchs is continuing the northward migration. It will take 4 generations of these incredible, brightly-colored orange, black and white insects to reach destinations in Canada and our northern states before a super-generation of monarchs turns around this fall and flies up to 2,500 miles back to the same trees that hosted the monarchs we visited in March.

Those of you who faithfully read the articles about the magnificent trees of the White Mountains will notice this slight departure, but it is the trees in Mexico’s highest mountains that provide the critical habitat that makes it possible for the monarch butterflies to survive the winter there. Principally, a species of true fir (Abies religiosa) called Oyamel in Mexico and some

Pictured at far left, a Monarch fuels up on local flower before starting migration. At left, a Monarch mural on building in rural Mexico and just a fraction of the 1.3 million seedlings being grown this year by Forests for Monarchs. Above, clumps of monarchs cling to each other during diapause and hundreds of monarchs take to the air in preparation of their northward journey.

high elevation pines, make up the forest that the monarchs seek as shelter. Without these protective trees covering high peaks that rise to 10,000 feet in elevation, the butterflies would freeze to death during winter storms as they hibernate. Mountain mists keep the monarchs from drying out during the 5 months they are resting there. The monarch’s wings have small overlapping scales which are highly hydrophobic. Moisture doesn’t soak in. If it did, the wings would stick together when they touched and the insect would die. The conditions have to be almost perfect for the monarchs to make it through the winter months.

Photographs shown in this article were all taken in March when weather conditions warm sufficiently to bring the monarchs out of their hibernation, technically called diapause, prior to their northward migration. After 5 long months hanging from the trees in Mexico, the butterflies are hungry and thirsty. They will drink nectar from available flowers, mate, and head north.

People who live along monarch migration paths also need to recognize the importance of the different milkweed species upon which the monarch caterpillars feed. It is essential to ensure that these plants remain available for monarchs to lay their eggs. Monarchs in Arizona actually migrate to coastal California, but the same dictates apply and gardeners who plant milkweed aid in monarch’s survival. Vicki Matsumonji with the White Mountain Community Garden wrote about the importance of milkweed in a series in the White Mountain Independent a couple years ago.

The tiny eggs that are laid on available milkweed plants hatch into green caterpillars that gain not only sustenance from their host but also retain poisons, a cardiac glycoside, from the plant that protect the adult butterfly from predators. The bright coloration of monarchs is actually a warning that they are not to be messed with. Viceroy butterflies, which are not poisonous but are similarly colored are able to use mimicry to also avoid most predators.

If everything goes right, the caterpillars gain weight incredibly fast and can go through 4 molts (instars) before the final molt when they change into a beautiful light green chrysalis with bright gold dots on one section. Inside the chrysalis the former caterpillar turns into a beautiful butterfly and the monarch butterfly we are familiar with emerges ready to take flight once its wings expand and dry. get their nourishment from a wide variety of flowering plants. Butterflies, like hummingbirds, bees and bats play an invaluable role as pollinators in plant life cycles even while enriching their own. When it comes time to lay their eggs, however, the monarch again seeks out one of the many varieties of milkweed.

Unfortunately, monarch populations have crashed significantly due to continued encroachment on over-wintering forest sites, widespread insecticide use on crops and lawns along migration paths, loss of milkweed habitat for caterpillars, large wildfires and drought. In Mexico, an organization called La Cruz Habitat Protection Project (Forests for Monarchs in the United States) works tirelessly to reforest critical high altitude forests upon which the monarchs depend. This year they are growing 1.3 million trees to help in this effort. (See forestsformonarchs. org for more information). It is just as important for American and Canadian organizations to also work to protect habitat along the monarch’s flyways to ensure that this magnificent migration continues well into the future.

About the author: Ron is a retired Forester and Silviculturist. He has lived and worked in the White Mountains since 2002. He can be reached at azron333@ yahoo.com.