The adult monarch's wings are reddish brown with black veins and a black boarder with two rows of white dots. Even though the monarch weighs only 0.5 gm (0.02 ounce), their wingspan may be 10 cm (4 inches).
During the fall, monarchs found east of the Rocky Mountains migrate to central Mexico, while those found west of the Rockies migrate to the California Coast. The migratory groups meet in the same places each winter. In these places, such as Pacific Grove, California, the trees will be covered with monarchs.
Mating begins near the end of winter. When March arrives, the monarchs leave their winter homes and begin flying north. During the journey north, the females lay eggs on the underside of milkweed plants, and then die shortly thereafter. The monarch caterpillars feed only on milkweed. The offspring will migrate to the same regions where their parents lived the previous summer.
While feeding on the milkweed plants, the larvae acquire a poisonous substance that makes them very distasteful to birds. Most birds learn to recognize the monarch's bright color pattern and they will avoid them.
In order to attract monarchs, gardeners should plant milkweed in large clumps. Milkweed should also be planted in full sun, sheltered from wind. A gardener may also want to plant nectar bearing flowers such as lilac or butterfly bushes, near the milkweed for the adults to feed on.
Carrie Covington & Beth Whisenhunt
ENT 301, Fall 2000
