Arthropod
of the Month
This month's elegant Arthropod is the Monarch butterfly. Both males and females have beautiful orange wings adorned with black stripes and white spots. Their original home is the United States but they can now be found in Southern Canada, Australia, and the Pacific Islands. Monarch's live for an average of 6 months or more. They feed on the nectar of flowers and lay their eggs on the underside of the milkweed plant.

The monarch undergoes four changes in form (metamorphoses) during its lifetime. Their pin-sized eggs have a short incubation of 3-5 days before they emerge as tiny caterpillars. In this caterpillar/larval stage they are characterized by smooth exoskeleton with stripes of black white and greenish yellow and two sets of feelers at both head and end of abdomen which has hooks. Caterpillar's may shed their exoskeletons several times within the 3 week period of growth, only to rely on a new layer of exoskeleton that has formed below. After the 3rd week the caterpillar is fully grown and ready onto move on the next stage in its development. It spins a clump of web on the milkweed and holds it with its caudal hooks, hanging downward, in a hook shaped position. It lays dormant for several hours during which its stripes begin to fade and it swells to a larger size. After about six hours, the caterpillar uncurls stretching downward becoming long and straight, soon thereafter its exoskeleton starts to split, wrinkles and falls off. The caterpillar now transforms into a beautiful chrysalis(pupa), shrinking until it is only 25 millimeters long. The whole process from when the caterpillar first hangs itself until it becomes a newly formed chrysalis is about 18 hours. Chrysalis is greenish-blue in color with bright golden spots. After about 12-15 days the butterfly is ready to hatch, it splits open the chrysalis and emerges transformed. It will not fly until its wings have been warmed by the sun, resting until its wings have hardened and are ready for flight. The entire process takes about a month. Usually three to four generations of monarchs grow in a given year.

While most insects hibernate, the monarch is the only species of butterfly which actually flies to warmer weather (migrates)during winter to a warmer climate. Monarchs from Illinois spend their winters in California and Mexico. In the fall, people have reported seeing entire trees covered with thousands of migrating monarchs!

Monarch Links
UKansas Monarch Watch Everything about Monarch butterflies.Monarch Butterfly Project General information on Monarch's.Journey North Global study of butterfly migration, journey archives and orginization information. Monarchs And Migration In depth information on the Monarch and how one can investigate them.

  updated by Ian Lally (beforeumass@hotmail.com)