An Exercise in Active Learning (Grades 2-4)
ON THE WING
One morning about ten days later, the beautiful jade-green case began to change to a teal blue and then gradually became darker. Within hours, orange wings were becoming visible in the now transparent case. Gulliver began to stir and the now frosty cuticle of the chrysalis soon broke open. Fragile black legs and a head with two antennae emerged first. The short, fat antennae he had as a caterpillar were now long and elegant.
After a short rest, Gulliver emerged the rest of the way. His body, which had once been yellow and black striped, was now very large and black with tiny white spots on it. His soft, crinkled wings were very small and damp, with a brilliant orange with black pattern. Gulliver hung from the empty chrysalis slowly moving his wings in the sunlight. Within minutes his large, fat abdomen got smaller and his wings had expanded to full size revealing a background color of bright orange. In contrast to the orange, black lines followed the veins which radiated from the base of each wing. Because he was a male, Gulliver had a small, but distinctive, black pouch along a vein on the upperside of each hindwing.(9) The wings were covered with a fine powder and some of the powder and color was lost whenever Gulliver rubbed against an object.(6) He clung to the frosty shell for almost an hour gaining the strength he needed for flight.
Gulliver was indeed quite different from the caterpillar who had spun himself a silken button under the log in the old wood pile about ten days before. His full beauty was now evident and he was a splendid sight. He no longer had the strong jaws for chewing leaves that he once had. They had been replaced by a long, black coiled tongue called a proboscis that would enable him to take in the nutrition his body would require for energy. The simple eyes which had barely allowed him to distinguish between light and dark were now huge, complex and specialized for seeing while in flight. The five pairs of legs on the abdomen of caterpillar used to cling to leaves were now missing. On the thorax he had long, elegant black legs, six to be exact. However, he only used two pair of legs to cling to flowers and other vegetation. The first pair of legs were very small and hidden from view.(2, 7)
At last, Gulliver's wings were ready for flight and he needed his first meal as a butterfly. He was ready to live his new life floating on the breezes. He lifted off and sailed effortlessly across the field.
There were other Monarchs like himself in the field as well as other butterflies and insects. Soon he could smell the sweet scent he had been searching for.(2, 8) He spread his glorious wings in the sunshine as he flew from blossom to blossom sucking up the sweet nectar. Like his ancestors before him he was not here just to grace our world with his beauty and spend his life drinking nectar from flowers. He and the other Monarchs also performed a necessary service to the flowers they visited.(9) As they moved from plant to plant, they carried pollen from one flower to another pollinating these flowers and assuring the production of seeds for milkweed for the next generation of Monarchs. The field was alive with color and movement. Butterflies and insects were everywhere and it looked like a painting in constant motion.
Gulliver's parents and grandparents had spent their entire brief lives in the field and the surrounding area. It was the only world they had known. But this was not Gulliver's destiny. He was part of the last generation of Monarchs to hatch for the summer, the migrant generation, and would be going on a great adventure that we humans find ourselves in awe of- the great Monarch migration to Mexico.(10) Gulliver would not mate at this time since his reproductive system was not fully developed. Rather, he would spend his days gathering nectar and his nights sleeping.
The days were beginning to get shorter and cooler. The flowers in the area were gradually disappearing and the leaves on the trees began to change. Gulliver had spent much time feeding on the nectar of flowers to provide energy for his flight southward. The extra nectar was converted to body fat which was stored in his abdomen. He would need energy to make the long flight to the roosting areas in Mexico and would need this body fat to survive the winter at the roosts.
Soon Gulliver was compelled to leave the meadow and the warm September heat. The days were getting shorter and it was time for Gulliver's adventure to begin. Up to now he had lived his life in a solitary fashion but soon would become a part of a large flight of others like himself, all instinctively aware that a bad time was coming and they needed to move on. Where was he going? How did he know how to get there? Certainly his parents and grandparents had not imparted this knowledge to him. They had never been there nor were they even alive when he was born. How mystifying!(11)
Toward the end of the first week's flight, when the sun began to redden and the temperature dropped, Gulliver again found a tree where he could spend the night. He often clung to a branch on the southeast side or in a place where the last sun of the day hit the trees, On this particular night, Gulliver found that scattered around the branches were Monarchs like himself who were also roosting there for the night in preparation for the next day's flight. He had never been with so many others like himself. With wings folded in, they looked like dead leaves hanging from the limbs. Their natural beauty was now hidden from view.
As the sun rose the next morning, a warm breeze blew from the south. By nine o'clock the rays warmed the place the Monarchs had spent the night and one by one they left the branches to begin their journey once again. Each went in search of nourishment and took deep drinks from the nectar in the flowers they found. Throughout the day other Monarchs joined them. Unlike birds, however, they seemed to fly more separately. Each chose his own path and stopped wherever and whenever they wanted.
By the end of the day some went further on and a few descended into a nearby group of pine trees for the night. The pine needles were easy for them to hang on to. Maples and willows were also good choices for roosting sites. Each night there were often a few new Monarchs that arrived to roost with the others for the night. However, there were still so few that they could not easily be seen by humans.
Some days nature afforded Gulliver and his fellow travelers with the gift of wind from a favorable direction and with its help they could easily fly great distances.(12) However, for the most part, his was still a solitary journey and he was forever alert to motion close to him. Indifference to danger could quickly bring an end to his journey.
Gulliver had been flying for several weeks always in a Southwest direction. It had been an arduous journey and the weather was an important contributing factor to the success of his journey. There were headwinds, crosswinds and storms to contend with in addition to calm days. On windless days he could only travel about six miles an hour since it required a good deal of effort on his part and used up more of his reserves. But with good side winds from the Northeast or Northwest he could go much further. And, if he flew up to ten hours a day, he made real progress.
Gulliver and the other Monarchs would often rise and soar like birds in the thermals, columns of warm rising air. At the top of the thermals, the Monarchs, with their wings outstretched, began long gliding flights in a South or Southwest direction until they found the next thermal. Other times they flew rather close to the ground apparently aware of their location relative to their destination. Temperature and sunshine were also important. If it was too cold or too warm or windy they made little progress causing Gulliver and his fellow Monarchs to take shelter. When they were unable to feed on flowers they had to obtain energy from the fat reserves stored in their abdomens.
The long journey had begun to take its toll on Gulliver. One of his wings was slightly torn and his color was not as intense as it had once been. He looked more fragile but he was still very strong and unless he met up with some cruel trick of fate he would make it to his winter home in Mexico.
Finally, one day in mid December, Gulliver reached his destination. His trip had been successful and he would overwinter in the Oyamel fir forests in the transvolcanic mountains West of Mexico City with millions of others like himself. They, too, had been travelers on the wind risking their lives to make the long journey.(13) For the next several months Gulliver and the others would spend their days roosting in the Oyamel fir trees, basking in the sun. When temperatures permitted they would search for nectar and drink water from the nearby stream. They had earned this well-deserved rest.
Gulliver had begun this flight in the first week of September and arrived at his destination in Mexico two and a half months later having flown 2,600 miles. This is indeed a long journey. What would this mean in human terms? Can you think of something equally as difficult for us?