Critter Catalog

What do they look like?

Both male and female monarchs are bright orange with black borders and black veins. The veins on the female are thicker than those of the male. Male monarchs also have a swollen pouch on both of their hind wings.

Monarchs are poisonous to vertebrates. Their poison comes from the milkweed they feed on.

Monarchs also use their appearance to ward off predators. Orange is considered a warning color, which will warn predators that monarchs are poisonous, and not to attack them. From a distance, monarchs can blend into their surroundings. Sometimes, their spots will appear to be the eyes of a larger animal, and will ward off predators.

• Other Physical Features
• ectothermic
• bilateral symmetry
• poisonous

• Range wingspan

  8.6 to 12.4 cm

  3.39 to 4.88 in

Where do they live?

Monarch butterflies are found in North America, South America, the Caribbean, Australia, New Zealand, islands in the Pacific Ocean, Mauritius, the Canary Islands of the Atlantic, and Western Europe.

What kind of habitat do they need?

Monarch butterflies prefer warmer climates; they cannot tolerate frost. They like open country. Females spend much of their time around searching for or staying near the main food plant for the caterpillars (see food habits section). Monarch butterflies require thick tree covering during the winter. In California, they live in eucalyptus trees. These eucalyptus trees are not normally found in California, but were put there to replace trees that had been cut down. Biomes: temperate forest and rainforest, temperate grassland, chaparral, tropical rainforest, tropical deciduous forest, tropical scrub forest, tropical savanna and grasslands, mountains

How do they grow?

Small caterpillars hatch from eggs laid by female Monarchs. They grow, shedding their skin to get bigger. Eventually each caterpillar stops growing and forms a case around itself called a chrysalis. Inside the chrysalis it changes its body its body in a process called metamorphosis. When it is done it emerges as an adult butterfly.

• Development - Life Cycle
• metamorphosis

How do they reproduce?

The mating period occurs in the spring, just prior to migration from the overwintering sites. The courtship of D. plexippus is fairly simple and less dependent on chemical pheromones in comparison with other species in its genus. Courtship is composed of two distinct stages, the aerial phase and the ground phase. During the aerial phase, the male pursues, nudges, and eventually takes down the female. Copulation occurs during the ground phase and involves the transfer of a spermatophore from the male to female. Along with sperm, the spermatophore is thought to provide the female with energy resources that aid her in carrying out reproduction and remigration.

• Key Reproductive Features
• semelparous
• sexual
• fertilization
  • internal
• oviparous

• How often does reproduction occur?

  Monarch butterflies mate in the spring before they migrate.

How do they behave?

Like birds, monarch butterflies migrate every season. In North America, some breed in the east and others breed in the west. Each autumn, monarch butterflies leave their breeding grounds for the winter months. Monarch butterflies that live in the east goes to volcanic mountains in Central Mexico. Monarch butterflies that live in the west go to parts of California during the winter.

What do they eat?

Monarch females lay their eggs on milkweed plants (Asclepias), these plants are then the main food for the caterpillars. Adult monarchs feed on nectar from many kinds of flowers.

How do they interact with us?

Some milkweed plants are poisonous to cattle. Monarch butterflies help reduce the amount of these plants.

Are they endangered?

The places where monarchs spend the winter are threatened. The United States and Mexico are trying to help the areas where monarch butterflies migrate.

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Contributors

Ethan Kane (author), University of Michigan-Ann Arbor.

References

Boppre, Michael."The American Monarch: Courtship and Chemical Communication of a Peculiar Danaine Butterfly". pp. 29, 34 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Cockrell, Barbara J., Stephen B. Malcolm, and Lincoln P. Brower. "Time, Temperature, and Latitudinal Constraints on the Annual Recolonization of Eastern North America By the Monarch Butterfly". pp. 234 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Feltwell, John. 1993. The Encyclopedia of Insects. Prentice Hall, New York. Pgs. 111, 143.

Lane, John. "Overwintering Monarch Butterflies in California: Past and Present". pp. 337 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Lynch, Steven P. and Ronald A. Martin. "Milkweed Host Plant Utilization and Cadenolide Sequestration by Monarch Butterflies in Louisiana and Texas". pp. 107-108 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Malcolm, Stephen B. and Myron P. Zalucki. 1993. Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County. Preface, pp. 397-398.

Malcolm, Stephen B. "Conservation of Monarch Butterfly Migration in North America: An Endangered Phenomenon". pp. 358 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Schmidt-Koeing, Klaus. "Orientation of Autumn Migration in the Monarch Butterfly". pp. 282 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Snook, Laura C. "Conservation of the Monarch Butterfly Reserves in Mexico: Focus on the Forest". pp. 364 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Urquhart, Fred A. 1960. The Monarch Butterfly. University of Toronto Press, Toronto. Pg. 35.

Urquhart, Fred A. 1987. The Monarch Butterfly: International Traveler. Nelson-Hall, Chicago. Pgs. XIX, 173-177.

Vane-Wright, Richard I. "The Columbus Hypothesis: An Explanation for the Dramatic 19th Century Range Expansion of the Monarch Butterfly". pp. 183 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Van Hook, T. "Non-Random Mating in Monarch Butterflies Overwintering in Mexico". pp. 49 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.

Wells, Harrington, Patrick H. Wells, and Steffen H. Rogers. "Is Multiple Mating an Adaptive Feature of Monarch Butterfly Winter Aggregation". pp. 61 in Malcolm and Zalucki (eds.) Biology and Conservation of the Monarch Butterfly. Natural History Museum of Los Angeles County.