Species Spotlight: Monarch Butterfly

Questions and Answers

Why is the declining availability of milkweed a threat to monarch butterflies?
Their dependence on milkweed alone as a host plant, and declining milkweed abundance throughout the monarch range, is threatening monarchs.

What adaptation protects monarch butterflies?
The bright orange and black colors of the monarch warn predators that they are inedible, due to their diet of toxic milkweed. Few animals can eat monarchs without getting sick. Other nontoxic butterfly species, such as the viceroy butterfly, take advantage of the monarch’s defenses and have evolved to look exactly like them to fool predators. This phenomenon of nature is called mimicry.

How do monarch butterflies sense when it is time to migrate?
Monarchs know when it’s time to migrate south for the winter based on signals from the environment indicating the seasons are changing. When it’s time, the butterflies will lift up on air currents high into the sky and embark on their journey.

Habitat

Widespread in North America, with mountain forests in Mexico as their winter habitat.
Diet

The milkweed plant (Asclepias)
Threats

Climate change threatens to disrupt the monarch butterfly’s annual migration pattern by affecting weather conditions in both wintering grounds and summer breeding grounds.
Interesting Fact

The monarch butterfly is known by scientists as Danaus plexippus, which in Greek means "sleepy transformation."