monarch butterfly
Monarch
FWS Focus

Overview

Adult monarch butterflies are large and conspicuous, with bright orange wings surrounded by a black border and covered with black veins. The black border has a double row of white spots, present on the upper side of the wings. Adult monarchs are sexually dimorphic, with males having narrower wing venation and scent patches. The bright coloring of a monarch serves as a warning to predators that eating them can be toxic.

During the breeding season, monarchs lay their eggs on their obligate milkweed host plant (primarily Asclepias spp.), and larvae emerge after two to five days. Larvae develop through five larval instars (intervals between molts) over a period of 9 to 18 days, feeding on milkweed and sequestering toxic chemicals (cardenolides) as a defense against predators. The larva then pupates into a chrysalis before emerging 6 to 14 days later as an adult butterfly. There are multiple generations of monarchs produced during the breeding season, with most adult butterflies living approximately two to five weeks; overwintering adults enter into reproductive diapause (suspended reproduction) and live six to nine months.

In many regions where monarchs are present, monarchs breed year-round. Individual monarchs in temperate climates, such as eastern and western North America, undergo long-distance migration, and live for an extended period of time. In the fall, in both eastern and western North America, monarchs begin migrating to their respective overwintering sites. This migration can take monarchs distances of over 3,000 km and last for over two months. In early spring (February-March), surviving monarchs break diapause and mate at the overwintering sites before dispersing. The same individuals that undertook the initial southward migration begin flying back through the breeding grounds and their offspring start the cycle of generational migration over again.

Conservation

Note: the monarch is a candidate species and not yet listed or proposed for listing. There are generally no section 7 requirements for candidate species (see our Section 7 Questions and Answers on the Monarch), but we encourage all agencies to take advantage of any opportunity they may have to conserve the species.

Monarch Conservation Resources

FWS Monarch Initiative

Mid-America Monarch Conservation (MAFWA)

Western Monarch Working Group (WAFWA)

Scientific Name

Danaus plexippus
Common Name
monarch butterfly
Monarch
FWS Category
Insects
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Food

Characteristics

Food

​Monarch butterflies require healthy and abundant milkweed plants for laying eggs on and as a food source for larvae or caterpillars. By consuming milkweed plants, monarchs obtain toxins, called cardenolides, that provide a defense against predators. Additionally, nectar from flowers is needed for adults throughout the breeding season, migration and overwintering.

Characteristic category

Behavior

Characteristics

Behavior

​In the fall, in both eastern and western North America, monarchs go into a state of suspended reproduction, known as diapause, and begin migrating to their respective overwintering sites. This migration can take monarchs distances of more than 3,000 kilometers and last for more than two months. In early spring, surviving monarchs break diapause and mate at the overwintering sites before dispersing. The same individuals that undertook the initial southward migration begin flying back through the breeding grounds. After several generations of monarch offspring in the spring and summer, a new generation begins the fall migration for the first time.

Characteristic category

Lifecycle

Characteristics

Lifecycle

Monarchs begin their lifecycle as eggs, which are laid on milkweed plants and hatch after two to five days. The eggs hatch into larvae, or caterpillars, and progress through five instars over the next two weeks before pupating into a green chrysalis. An adult monarch will emerge one to two weeks later. 

Lifespan

Most breeding adult butterflies live approximately two to five weeks, but overwintering adults that enter into reproductive diapause can live six to nine months.

Reproduction

As temperatures warm at the overwintering sites in the spring, monarchs begin to breed and lay eggs on milkweed throughout their migration. The following generations breed and lay eggs throughout the summer. In the fall, monarchs enter a state where they stop reproducing, known as diapause. This allows them to focus their energy and resources on the long-distance migration and surviving the winter. Some non-migratory monarchs in warmer climates breed year-round.

Characteristic category

Geography

Characteristics

Range

Monarchs are native to North and South America but have since spread to many other locations where milkweed and suitable temperatures exist, including Australia, New Zealand and portions of the Iberian Peninsula.

Characteristic category

Physical Characteristics

Characteristics

Color & Pattern

Adult monarch butterflies are large and conspicuous, with bright orange wings surrounded by a black border and covered with black veins. The black border has a double row of white spots, present on the upper side of the wings. Adult monarchs are sexually dimorphic, with males having narrower wing venation and scent patches. The bright coloring of a monarch serves as a warning to predators that eating them can be toxic. 

Physical Characteristics

The large and brightly colored monarch butterfly has two sets of wings that span three to four inches. Monarch caterpillars, or larvae, have black, yellow and white stripes and reach lengths of two inches before metamorphosis.   

Measurements: Wingspan: 3 to 4 inches (7 to 10 cm) Larval length: 2 inches (5 cm) 

Size & Shape

The large and brightly colored monarch butterfly has two sets of wings that span three to four inches. Monarch caterpillars, or larvae, have black, yellow and white stripes and reach lengths of two inches before metamorphosis.   

Measurements: Wingspan: 3 to 4 inches (7 to 10 cm) Larval length: 2 inches (5 cm) 

Weight

Monarchs weigh, on average, about half of a gram, which is less than the weight of a paperclip.

Characteristic category

Overview

Characteristics

Overview

With its iconic orange and black markings, the monarch butterfly is one of the most recognizable butterfly species in North America and is known for its impressive long-distance migration.  

Characteristic category

Habitat

Characteristics

Habitat

Whether it’s a field, roadside area, open area, wet area or urban garden, milkweed and flowering plants are needed for monarch habitat. Adult monarchs feed on the nectar of many flowers during breeding and migration, but they can only lay eggs on milkweed plants.

For overwintering monarchs, habitat with a specific microclimate is needed for protection from the elements, as well as moderate temperatures to avoid freezing. These conditions vary between populations. For the eastern North American population, most monarchs overwinter in oyamel fir tree roosts located in mountainous regions in central Mexico at an elevation of 2,400 to 3,600 meters. Monarchs living west of the Rocky Mountain range in North America primarily overwinter in California at sites along the Pacific Coast, roosting in eucalyptus, Monterey pines and Monterey cypress trees. 

Grassland

Land on which the natural dominant plant forms are grasses and forbs.

Tundra

A level or rolling treeless plain that is characteristic of arctic and subarctic regions with permanently frozen subsoil.

Urban

Of or relating to cities and the people who live in them.

Rural

Environments influenced by humans in a less substantial way than cities. This can include agriculture, silvaculture, aquaculture, etc.

Wetland

Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.

Mountain

A landmass that projects conspicuously above its surroundings and is higher than a hill.

Coastal

The land near a shore.

Geography

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Timeline

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