The astounding Monarch Butterfly voyage
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Here is a detailed article on one of most impressive natural journeys that is also part of Mexico’s Traditions, the voyage of the Monarch Butterfly from North America to Mexico.
Year after year when autumn comes, following a millennial call whose origin remains a puzzle to Man, the monarch butterfly of North America undertakes the longest known voyage in the insect world.
After spending the summer season in the rich fields and forests of central and northeastern USA and southeastern Canada, millions of these delicate insects start a three thousand mile migration voyage south so that they can survive the winter in central Mexico’s magnificent Sierra Madre Oriental mountains and hills.
The last stop of the monarch butterfly (Danaus plexippus) was for a long time a mystery for researchers. But in 1975 the Canadian zoologist Doctor. Fred A. Urquhart, together with Kenneth Brugger and Rafael Sanchez Castaneda, discovered their secret. The butterflies were enjoying the frigid months of winter in the dry stream beds and valleys of the high Sierra Madre mountain range, at an altitude of 9 to 10,000 feet in an area that is located between the states of Michoacan & Mexico State, in the central area of Mexico.
Urquhart wrote about their discovery: “I watched in surprise at the view. Butterflies, millions and millions of monarch butterflies! They stuck in thickly packed masses to each and every branch and tree trunks of the tall, gray-green oyamel trees. They swirled thru the drafts like autumn leaves and covered the ground in their flaming colored myriads on this Mexican hillside.”
This discovery provided one of the most superb revelations about the natural world. Suddenly, as if drawn by a forceful magnet, these frail summer residents of a massive territory that covers over half of the United States, migrate south in hurried hordes in an excursion that takes them south over prairies, valleys, mountains, deserts and cities, crossing the Mexican border thru Texas, to converge by the millions, like orange-colored tributaries of some great stream, into a region in central Mexico where the Sierra Madre and the Volcanic Belt mountains meet.
A relatively modest sized forest of only 12,500 acres is the sanctuary where the monarch butterflies pass the winter and copulate before returning up north again in the spring months.
Even though this seemed to be a fantastic discovery for the scientific community, it was considered general knowledge to the area’s inhabitants. These creatures had been part of their daily lives since time immemorial. Pre-Hispanic inhabitants attached great importance to the monarch butterfly, which played a major role in their local religion, myths, and were regularly pictured in their art.
Connected with fire and the movement of the sun, butterflies or papalotl represented the spirits of soldiers who had died in battle or on the sacrificial altar. It was thought that after travelling with the Sun for four years, they might come back to earth as a butterfly, to enjoy the sweet nectar of flowers. This belief, in all probability, also applied to monarch butterflies, “daughters of the Sun” whose yearly migration represented the replenishing cycle of Nature.
In 1986, eleven years after Urquhart’s discovery, the Mexican Govt protected this ecologically important mountain area by establishing the Monarch Butterfly Special Ecosphere Reserve. A total of around forty thousand acres of forest were declared protected areas for the migration, wintering and reproduction of the monarch butterfly, as well as for the conservation of its vital environment.
The Monarch’s Summer Home
During the summer, monarch butterflies live in an area that includes 1.5 million square miles and that extends from southern Canada to the southern tips of the Sierra Nevada, the Rocky Mountains to the West and the Appalachians to the East within the U. S. of America. This area is full of milkweed (Asclepias), the sole plant on whose leaves the caterpillars of this species can feed. This plant also has a toxic alkaloid that makes the caterpillar unattractive to many natural predators, and provides the natural pigment which gives these butterflies their unique coloration.
The longer days and high summer temperatures of this area permit the monarch butterfly to mature and reproduce. During those months, its life cycle is like that of any butterfly. They live from two to 6 weeks, in which they court, lay their eggs and, immediately after that, die.
Nonetheless the generation that emerges from the cocoons under the Sep sun has a completely different destiny than that of its parents and grandparents. After the fall equinox, as the days grow shorter and temperatures go down, the autumn butterflies endure a sequence of hormone changes which hold back their reproductive system, forestalling sexual maturity, and permitting them to save energy and survive much longer than their progenitors.
Rather than triggering the desire to copulate, the shortening days create in these creatures another vital need, just as important for their survival as reproduction… An urge to migrate south, toward hotter lands where they can survive the winter chills, postponing their mating rituals till the following season.
So, they must travel to preserve the species. If they survive the dangerous journey, they can live as long as nine months, twelve times longer than any other butterfly.
The Great Monarch Butterfly Journey
After storing enough energy and fat in the summer months, these indefatigable travelers will fly as much as 3,000 miles to reach their Mexican wintering grounds. They fly twenty four seven, and rest in the night, sleeping on tree branches in groups of nearly 600 butterflies.
Dependent on the winds, they can travel at a velocity from nine to twenty-seven miles an hour, covering as much as 80 miles in daily eight-hour shifts. Their favourite routes lie along low open valleys, where they can best take advantage of the north winds to push them along in open-winged glides, which enables them to fly long distances easily. This is the way the monarch butterflies can make their 3,000 mile journey in only one month.
By mid-November, the green crevasses of the Mexican butterfly sanctuaries, inhabited by oyameles or firs, oaks and spruces, change to shades of ochre, brown and orange. Leaves and pine needles become frosted with a strange texture created by the wings of the millions of butterflies that hang in thick clusters, from the tree branches. Here they survive the winter cold, in a state of semi-hibernation that allows them to save their energy and fat till spring arrives.
The Monarchs voyage back north
Warmer days and longer daylight hours send their age-old signals to the sleeping monarchs telling them that spring has returned. They start to stir and flap off the sleepiness of their long sleep. They slowly open their wings to let the sun heat in and to warm their bodies.
Little by little the air comes alive and orange tinted, with hundreds of butterflies that flutter around from flower to flower collecting the sweet nectar which will nourish and give them strength for their homeward journey.
Light, heat, and their new-found liberty excite their sexual maturity once again. Their buried instincts take over, giving way to courting rituals and copulation. And then, without further circling, just as when they suddenly started their trip south five months before, as if moved by an internal clock that urges them to go back home, they begin their return journey. Hordes of butterflies rise up into the air, their thrashing wings creating a muted throb looking for air currents that may carry them away.
Their numbers have already been lessened. Many have died of the rain or from the winter temperatures. Mating has also taken a toll on the majority of the males, who invested their last energy supplies in the reproductive act, and then perished.
But among the survivors are a large number of fertilized females who, during their way back home, will deposit their eggs on their nightly stops to rest. Two weeks later these eggs will hatch into caterpillars, which will soon become chrysalis that, in the late spring, will metamorphose into butterflies.
Of these, only a few will remain to copy the cycle there, where they were born. The rest will continue northward to a home they don't yet know, where, like countless generations before them, they are going to live, friend and die. And it will not be their young, or their offspring’s young, but the next generation of butterflies, those born at the end of summer that may again respond to the call to migrate south, as their ancestors did the year before, beginning another cycle.
The Conundrums of the Monarch Butterfly
It's still a puzzle how these miniscule, delicate insects know which route to follow, since the winter visitors were born in the distant forests of the United States and Canada, and the monarchs procreated in Mexico will never return there.
How does a whole generation of monarchs travel an one or two thousand mile route that neither they, nor their mother and father, have ever flown before? How do their descendants, born after the winter season along the migration back north, manage to find a way to go back to their parents’ place of origin?
Again, how does such a tiny, frail and exposed creature come up with a way to survive the rigors of traveling such long distances exposed to the sun, the rain, the cold and the depredation of man? Where does such a tiny body accumulate so much energy? What makes it so tireless? How can an insect be so magnificent?
Many answers have been suggested for these paradoxes, but still none is final. But one thing is clear. The monarch butterfly is one of the most amazing creatures on the planet Earth. And, the more we know about it, the more incredible it becomes.
This long distance traveler, citizen of the world, is the most delicate and lovely symbol of the metamorphosis and renewing of Nature. Above everything else , it is a prime example of a species’ instinct to survive.
Little wonder our ancestors venerated the Monarch Butterfly and this is why it’s so important that we protect them.
Guadalupe Q. Pali is a magazine editor in Mexico, writes many articles on traveling in Mexico and its natural wonders, including some like What to do in Puerto Vallarta, that’s part of the Puerto Vallarta’s Travel Guide
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