Monarch

Danaus plexippus

The Life Cycle of the Monarch Butterfly

The life cycle of a Monarch Butterfly starts with a tiny egg, which hatches into a caterpillar. The caterpillar feeds on milkweed plants, which are the only plants on which Monarchs lay their eggs. As the caterpillar grows, it sheds its skin multiple times in a process called molting. After the final molt, the caterpillar forms a chrysalis, which is a protective casing that it uses to transform into an adult butterfly. The butterfly emerges from the chrysalis and begins its short but eventful life.

Migration Patterns of Monarch Butterflies in the Western United States

Monarch Butterflies are known for their incredible migration patterns, which take them thousands of miles across North America each year. In the Western United States, Monarchs typically migrate to California and Mexico during the fall and winter months. In California, Monarchs can be found along the coast, where they overwinter in large clusters in eucalyptus trees. In Mexico, Monarchs gather in the oyamel fir forests of the Sierra Madre mountains, where they form massive colonies that can number in the millions.

Nectar Plants in the Sonoran Desert

During their migrations, Monarch Butterflies need to refuel by feeding on nectar from a variety of plants. In the Sonoran Desert of the Western United States, there are several nectar plants that are especially attractive to Monarchs. Some of these plants include milkweed, thistle, asters, and desert willow. These plants provide the necessary nectar for Monarchs to continue their journey, and also serve as important habitat for other pollinators.

1. Desert Milkweed (Asclepias erosa) Desert Milkweed is a native milkweed species that is found throughout the Sonoran Desert. It produces clusters of small, pinkish-white flowers that are highly attractive to Monarchs and other pollinators. Desert Milkweed is also the primary host plant for Monarch caterpillars in the Sonoran Desert.
2. Mexican Hat (Ratibida columnifera) Mexican Hat is a hardy native perennial that produces distinctive red and yellow flowers that resemble a sombrero. It blooms from early summer to fall and is a favorite nectar plant for many butterfly species, including Monarchs. Mexican Hat is an easy-to-grow plant that prefers full sun and well-draining soil.
3. Desert Marigold (Baileya multiradiata) Desert Marigold is a native perennial that produces bright yellow flowers. It blooms from late winter to early summer and is an excellent nectar source for Monarchs, as well as other pollinators. Desert Marigold is easy to grow and is a great choice for anyone looking to create a Monarch-friendly garden in the Sonoran Desert.
4. Arizona Milkweed (Asclepias angustifolia) Arizona Milkweed is a native milkweed species that is found in the Sonoran Desert and other parts of the southwestern United States. It produces small clusters of pinkish-white flowers that are highly attractive to Monarchs and other pollinators. Arizona Milkweed is also the primary host plant for Monarch caterpillars in some parts of the Sonoran Desert.
5. Yellow Bells (Tecoma stans) Yellow Bells is a native shrub that produces clusters of bright yellow flowers. It blooms from late spring to fall and is highly attractive to Monarchs and other pollinators. Yellow Bells is an easy-to-grow plant that prefers full sun and well-draining soil.

Larval Host Plants

While Monarchs feed on nectar during their migrations, they also rely on specific plants for laying their eggs and feeding their young. As mentioned earlier, Monarchs lay their eggs exclusively on milkweed plants, which serve as the only larval host plant for the caterpillars. Other species of milkweed can be found throughout the Western United States, providing vital habitat for Monarchs and supporting their continued survival.

For additional information, visit Butterflies and Moths of North America.