Monarch butterflies are world traveling insects. They have a bright orange and black pattern that is easily recognizable. Many are captured by the beauty and elegance of the butterfly. However, a lot of people are unaware of just how complicated a monarch’s life can be. From egg to adult, they go through a lot of change, and it doesn’t stop there. A certain generation takes the feat of traveling thousands of miles to hibernate. If that wasn’t enough for one little butterfly, they are being threatened by logging and climate change.
Butterflies have a complicated and intricate life cycle. The monarch goes through four stages in a life cycle: egg, larva, pupa (chrysalis), and adult. In the months of March and April, eggs are laid by female monarchs on milkweed plants. After four days, the egg hatches and a caterpillar comes out marking the beginning of the larva stage. The caterpillar spends most of its time feeding on milkweed gathering enough nutrients for the big metamorphosis event. Monarch caterpillars only eat milkweed and nothing else which is why they are sometimes called the “milkweed butterfly.” After engorging themselves, caterpillars are then ready to begin the pupa or chrysalis stage. First, the caterpillar attaches itself to a stem or leaf and then uses silk to build itself a cocoon or chrysalis. The chrysalis of the monarch is green with a beautiful gold strip at the top. Inside the chrysalis, the caterpillar is going through metamorphosis. There are special cells inside the caterpillar that are now developing into legs, wings, eyes, and other parts of the adult butterfly. After ten days, the adult monarch emerges from the cocoon. After two to six weeks, the first generation lays eggs and dies. The second generation goes through all the life cycles, emerges, lays eggs and dies. The third generation does the same as the first two generations. The lucky fourth generation, born in September, is the generation that gets to travel to Mexico or California.
The fourth generation monarchs migrate to the warmer climates of Mexico or California during the winter months. Monarchs make a 2,500 mile journey every year to the same trees. They like to hibernate in oyamel fir trees in Mexico and eucalyptus trees in California. Instead of living only for six weeks, fourth generation monarchs live for six to eight months. They must travel back north in the spring to lay their eggs on the milkweed plants. Fat stores in their abdomen allow the adults to make a 5,000 mile round-trip. They will even make pit stops along the way and refuel on nectar.
Since monarchs migrate and hibernate in specific trees, they are being threatened by illegal logging and climate change. The adults only hibernate on 12 mountaintops that house the oyamel fir trees in Mexico. There are protected areas and reserves, but logging still occurs in these areas. In 2007, Mexico launched a conservation plan that focused on a zero tolerance policy of illegal logging. The president deployed soldiers to the monarchs’ hibernation area to search for loggers. Along with the policy, 10 million trees were planted in the butterfly reserve.
Climate change is another threat to the butterfly’s migration. Years from now the mountains of Mexico where the butterflies hibernate may become too wet, because of the increased rainfall due to the earth’s changing climate. Monarchs don’t have a high tolerance for rainfall during their hibernation period. Scientists predict the butterfly will go extinct, find a new hibernation spot, or develop a tolerance to the new conditions.
Egg to adult, a monarch’s life can be somewhat complicated, especially if they are fourth generation. They start out as eggs and hatch into tiny caterpillars that engorge themselves on milkweed. Then, they go through the big change and develop into adults. After they spend all that energy developing the beautiful orange and black wings, they have to fly out to Mexico. Hopefully, they will be able to continue this migration for years to come in spite of the many challenges they face.
- “Butterfly Life Cycle | Butterflies | Academy of Natural Sciences.” Academy of Natural Sciences, Natural History Museum in Philadelphia. Web. 27 Sept. 2011. <http://www.ansp.org/museum/butterflies/life_cycle.php>.
- “Migration & Tagging : Fall Migration.” Monarch Watch. Web. 27 Sept. 2011. <http://www.monarchwatch.org/tagmig/index.htm>.
“The King of Butterflies-the Monarch Butterfly.” Monarch Butterfly Site: Life Cycle, Migration, Pictures, News, More! Web. 27 Sept. 2011. <http://www.monarch-butterfly.com/index.html#Life-Cycle>.