Dr. Mecca’s biology classes are experiencing a new phenomenon in his biology classes. Just days before the start of school Dr. Mecca came across sixteen monarch caterpillars, or larva, while working in southeastern Pennsylvania doing field work on streams this summer. He decided to capture them and show his students the miracle of metamorphosis while looking at “life cycles, mimicry, food chains and habitat,” he explains.
As a biology teacher Dr. Mecca must teach his students about the life cycles of insects, especially monarchs’, but never before has he been able to literally have his class take part and study the unknown mysteries of insect transformation. “We really have no idea what is going on while [the larva] are in the cocoon.” The only visible change is the color of the cocoon itself.
“Each larva goes through 5 stages called instars.” An “instar” as given in Merriam-Webster Dictionary, is a “stage in the life of an arthropod (as an insect) between two successive molts”; a molt is a term used to describe the “shedding” of an outer layer. As the larva develops through the “instars,” its cocoon changes color from a crisp apple green to a translucent brown; however, the most intriguing detail on the monarchs cocoon is the small golden dot formations. Dr. Mecca admits he doesn’t know what these golden dots might be. But that is the beauty of this incredible insect. Looking at the cocoon, it seems as though someone had painted gold designs to tell the difference between larvas, but in actuality that is part of the cycle.
This year could not have been a better year to discover these insects. With the completion of the Butterfly Garden last spring, Dr. Mecca is presented with the perfect location to release the butterflies after they have broken out of their cocoon. “Releasing them in the butterfly garden provides the monarchs with an opportunity to obtain some food for their trip to northern Mexico. It also permits them to determine their geographic position for migration and exercise their wings in preparation for flight.” Mecca explains.
The whole cycle of life is beautiful; from the moment they begin to make their cocoon to when the color changes to a translucent brown and the color of the wings are visible. And even towards the end when the butterfly breaks through the cocoon and pumps blood through its wings to stretch and practice flying. Although a few of the larva were lost due to infection, Dr. Mecca could not be happier at the start of the school year. Visual learning is always a good tool but when that learning is kicked to the next level and students actually get to physically study the changes a monarch butterfly undergoes, the interaction and participation levels reach their highest.
| < Prev | Next > |
|---|
.png){kind=small}
