Every week, I drive to a designated field site that contains an abundance of milkweed and nectar plants. Milkweed is important because monarch caterpillars only eat plants in the milkweed family. Hence, female monarchs lay a single egg on the underside of a milkweed leaf*. Monarch eggs are the size of the head of a pin, yellow-white in color, are similar to the shape of an American football, and display radiating ridges extending from the top to the bottom. After 3-8 days, a tiny caterpillar will use its mandibles to eat its way through the egg and emerge. At first, a monarch caterpillar is a pale yellow-greenish color and is almost translucent. The hungry caterpillar will eat the leaf and molt as it becomes bigger in size. Caterpillars farther along their growth stage exhibit alternating bands of yellow-white-black colors. After 14-18 days, the caterpillar will usually leave its host, the milkweed plant, and travel to a nearby plant to pupate. Once inside the chrysalis, the monarch’s body transforms from a caterpillar to a butterfly.  A monarch can be in its chrysalis stage for one to two weeks. An adult monarch butterfly is distinguishable by its bright orange wings, black veins, and circular white spots along the perimeter of its wings. Lastly, the nectar plants in the field site serve as food sources for the adult monarch butterflies as they migrate or breed.

 For more information about the monarch butterfly’s life cycle, click on the following links:

Monarch Joint Venture: https://monarchjointventure.org/monarch-biology/life-cycle

Monarch Watch: https://www.monarchwatch.org/biology/cycle1.htm