The Life Cycle Of a Monarch Butterfly

The Life Cycle Of a Monarch Butterfly

Watching a monarch butterfly go through its life cycle is like witnessing a miracle unfold. From the moment it first emerges from its chrysalis to its distant migration across the continent, the monarch butterfly is one of nature's most remarkable creatures.

By understanding each stage of their life cycle, we can gain a better appreciation for these beautiful creatures and also admire the beauty of the monarch butterfly that fills our skies with color!

Throughout this journey, we'll examine each stage of the monarch butterfly's life cycle in detail. We'll explore how they feed and reproduce, how their wings help them fly, and why they migrate so far away each year. 

Egg: Tiny Beginnings 

It all starts with an egg! Monarch butterflies begin life as a small egg laid by females on milkweed plants. The eggs are usually about  1 mm in size and yellow or white.

Once laid, the eggs only take about 4-5 days to hatch, during which time their protective shell will turn a bronze color. A few factors can influence the hatching success rate of monarch butterfly eggs, such as humidity, temperature and windiness. 

Larva: Caterpillar Time

The second stage of a monarch butterfly's life cycle is the larva or caterpillar stage. This is when caterpillars emerge from their eggs and begin to grow and develop. They have a distinct physical appearance with black, yellow, and white stripes running along their bodies. 

The caterpillars grow through several molting processes called instars before they reach the full-grown stage. They go through 5 instants which simply means a process where they “shed skin”. 

Caterpillars eat a lot during this stage, munching only on milkweed leaves. Despite being such picky eaters the monarch caterpillars can double their weight every day and grow up to two inches long!

The duration of this larva stage varies depending on environmental conditions but typically lasts between two and three weeks before they form chrysalides. So while it may seem like a relatively short period compared to other life stages, it's full of exciting transformations and is essential for laying the foundation for adulthood.

Pupa: Chrysalis Magic

Once the caterpillar has eaten enough and grown to its full size, it's time to start the next stage of its life cycle: pupa or chrysalis! This is when things start to get exciting.

Formation of the Chrysalis

First, the caterpillar finds a safe spot and prepares to form a chrysalis. It often crawls away from the milkweed plant and finds a safe and covered area, this is so they don’t get disturbed by other caterpillars during the metamorphosis.

It then attaches itself to a stem or a leaf using silken threads and its saliva, then starts shedding its outer layer of skin - a process known as ‘ecdysis’. What is left is a green "envelope" called the chrysalis.


Next, metamorphosis takes place—the transformation from caterpillar to butterfly. During this stage, the monarch caterpillar’s body breaks down into liquid form and is reorganized into that of an adult butterfly. It's an amazing transformation!

Physical Appearance of the Chrysalis

Once the transformation is complete, the monarch's body is encased in an exoskeleton made up of gold-flecked black stripes. The golden stripes on the chrysalis are formed by tiny yellow spots on the surface of each wing—they look so stunning!

Duration of Pupa Stage

This stage lasts anywhere from 8 days to two weeks, depending on the temperature and humidity level. Once the chrysalis has undergone full metamorphosis, then it's time for the fourth and final stage - emergence!

Adult: Reaching the Final Growth Stage

The peak of the monarch butterfly’s life cycle comes with the adult stage - reaching its full growth. After emerging from the chrysalis, adult monarch butterflies become striking, eye-catching creatures with signature patterned orange and black wings.

  • Physical Appearance 

  • Adult monarchs can have a wingspan of up to 8.5 cm! They have distinct orange, black and white patterns on their wings. Males monarchs, that have distinguishing black dots along the veins of their wings, are slightly bigger than females. 

    Beyond the veins on their wings there are other ways of telling a male monarch butterfly apart from a female monarch. 

  • Feeding Habits and Nectar Sources

  • Adult monarch butterflies feed on nectar from flowers, using their long tongues (proboscis, a tube-like tongue) to reach into them. While they also eat certain types of sap found in rotting fruit or tree bark, they require energy sources like nectar to stay active during migration and breeding periods. By flying around looking for nectar and sap they help pollinate flowers they come in contact with. 

  • Mating and Reproduction

  • Reproduction begins with mating. Male monarchs will search for a female by flying around and releasing special chemical signals, called pheromones, to help the opposite sex locate them. Once a female is located, a pair will mate by clasping their abdomens together. The male then transfers sperm, contained in a sac known as a spermatophore, to the female– which she will store and use to fertilize her eggs. 

    During mating season (which typically lasts until mid-September and all year round in Hawaii), female butterflies will lay eggs on milkweed leaves - which is where the next generation of butterfly larvae will emerge after hatching! Over the course of her lifespan, the female can lay up to 400 eggs.

    The Monarch Butterfly's Life Span and Death

    The monarch butterfly's lifespan is quite remarkable. On average, the US mainland butterflies can live up to 10 months - an impressive feat for such a small creature! However, Hawaii monarchs live only 3 - 4 weeks.

    So what affects the lifespan of a monarch butterfly?

    Environmental Factors

    The weather has a big impact on the monarch butterfly's longevity. If it's too hot or too cold, they won't be able to survive. They migrate to warmer climates during the winter, but the changes to the climate can mess up their migration patterns and affect their lifespan. 

    This isn’t the case for the Hawaii Monarchs because it’s warm in Hawaii, there’s no need for them to migrate. 

    Predators, Parasites & Diseases

    For predators like birds and spiders, see Monarch Butterflies as a tasty snack. 

    Those are the obvious threats to the majestic monarch butterfly, but did you know there are some less obvious threats? For example, parasites that pass on their disease such as Ophryocystis elektroscirrha (OE). Scary name right!

    Human Threats

    We must also mention how people can affect the monarchs. Habitat destruction and insecticides can harm monarch populations by destroying their food, homes and mating environments. But we can help protect them by planting pollinator gardens with milkweed or creating safe spaces for them to live that can help preserve this majestic species for generations to come.

    In conclusion, watching a butterfly change is an awesome experience and a reminder of how amazing nature is. When you see a monarch butterfly, remember the miracle of its life cycle, which is complex and amazing, but so important for our planet.

    Through their incredible migration, monarch butterflies inspire us to keep going even when things are tough and to never give up on our dreams. They remind us to protect our Earth and its delicate ecosystems so that these majestic creatures and all living things can thrive for generations to come. It's a beautiful lesson in nurturing and growth.