An Awesome Explanation of the Life Cycle of a Caterpillar, Animal Sake

The caterpillar life cycle has four amazing stages. In this article we'll walk through each one, and share some jaw-dropping facts about these tiny creatures along the way. It is one of nature's most dramatic transformations: a wriggling leaf-eater that becomes a flying work of art.

The larval forms of moths and butterflies are known as caterpillars. Most caterpillars feed on plants. A few are entomophagous, that means they eat other insects instead! Caterpillars have a tubular body that is divided into segments.

Different Life Cycle Stages

The caterpillar is the second phase in the life cycle of a butterfly. The other phases are: eggs (first phase), pupae (third phase), and the adult butterfly (fourth and final phase). How long does the whole cycle take? It can be anything from a single month to a complete year, depending on the species. Below is each stage explained in detail.

Life Cycle of a Caterpillar diagram — The four-phase life cycle of a caterpillar, from egg through to adult butterfly.

Mini activity

Life Cycle Wheel

Choose the four stages in order and watch the wheel fill in.

1Stage 1
2Stage 2
3Stage 3
4Stage 4

Pick the first stage in the life cycle.

0/4

Egg Phase

This is the first phase in the caterpillar life cycle. Eggs come in many shapes, round, cylindrical, oval, and more. They are usually laid on plant leaves. Females can also lay eggs on stems. Placing eggs on leaves makes sense: the hatching caterpillar gets a meal straight away!

Each egg is protected by a hard outer shell called the chorion. A thin coat of wax on the inside of the chorion stops the egg from drying out. The egg phase generally lasts a few weeks. Eggs laid in winter go through a resting phase and only hatch when spring arrives.

Caterpillar Phase

A striped caterpillar feeding on a leaf, showing its true legs and prolegs — A caterpillar mid-meal: you can see its pointed true legs near the head and the stubby prolegs along the abdomen.

Caterpillars are hungry eaters and spend most of their time munching plant leaves. They grow through several stages called instars. At the end of each instar, the caterpillar sheds its outer skin, a process called apolysis. That outer layer is the cuticle, made of protein and chitin. Each shed allows the caterpillar to grow bigger.

A butterfly caterpillar has two types of legs. There are 3 pairs of pointed true legs near the head, and up to 6 pairs of stubby prolegs along the abdomen. Some caterpillars also have special organs called osmeteria, which pop out and release smelly chemicals to scare off predators.

Wing disks form on the second and third segments of the thorax. They grow quickly after the final instar phase. When the time comes, the haemolymph (insect "blood") pushes the wings out through the epidermis.

Caterpillar crawling along plant leaves — Breathing in caterpillars takes place by means of spiracles, tiny openings along the sides of the abdomen and thorax.

Test Your Life Cycle Knowledge!

5 quick questions about eggs, instars, chrysalises, and more.

Pupal Phase

A translucent jade-green chrysalis hanging from a twig with butterfly forming inside — The chrysalis (pupa) is where the real magic happens: the caterpillar's tissues are reorganised into a completely new body plan.

The pupa is the stage between the larva and the adult butterfly. When a caterpillar is ready to pupate, it stops eating and finds a safe surface to perform its final molt. As the pupal stage begins, a hormone called PTTH (prothoracicotropic hormone) is released. The wings grow rapidly inside and need lots of nutrients. To keep predators away, pupae can even make special sounds!

Adult/Butterfly Phase

The fully developed adult butterfly is called the imago. When it breaks out of the chrysalis, its wings are soft and crumpled. It takes about 3-4 hours for the wings to dry out and unfold fully. Only then can the imago fly properly.

Black caterpillar on a garden leaf — A black caterpillar on a garden leaf. Many caterpillar species use bold colors to signal that they are toxic or distasteful to predators.

Interesting Caterpillar Facts

Caterpillars breathe through small openings called spiracles. These are found along the sides of the abdomen and thorax, not through a nose or mouth!

The total number of muscles in a caterpillar's body is 4,000. The head segment alone has 248 muscles. That's remarkable for such a small creature.

Caterpillars have poor vision. On each side of the head there are six tiny eyelets called stemmata. They can sense light and dark, but caterpillars mostly rely on touch and smell to explore their world.

Some caterpillars can detect vibrations at specific frequencies. The Drepana arcuata caterpillar (Hook-tip moth) even protects its silk nest by producing sound waves to scare away rivals.

Frequently Asked Questions

What are the four stages of a caterpillar's life cycle?

Egg, caterpillar (larva), pupa (chrysalis), and adult butterfly or moth (imago).

How long does the egg phase last?

The egg phase generally lasts a few weeks, though eggs laid in winter may stay dormant until spring.

What does a caterpillar eat?

Most caterpillars eat plant leaves. A small number are entomophagous, they eat other insects.

How long does it take a butterfly's wings to dry after emerging?

About 3-4 hours. The wings must fully unfold before the butterfly can fly.

A few caterpillar species are poisonous. They can shoot toxic acids at predators to defend themselves.

The caterpillar life cycle gives us a window into the amazing world of butterflies and moths. There is so much more to discover about these tiny creatures, what you have read above is just the beginning!

Term	What it means
Chorion	The hard outer shell that protects a butterfly or moth egg. A waxy coat on the inside stops it from drying out.
Instar	One growth stage between two molts. Each time a caterpillar sheds its skin (cuticle), it enters a new instar, it may go through 5 or more instars before pupating.
Apolysis	The process of shedding the cuticle (the protein-and-chitin outer layer) at the end of each instar. This allows the caterpillar to grow larger.
Osmeteria	Fleshy, horn-like organs some caterpillars can push out (evert) to release smelly chemicals that deter predators.
Stemmata	Six tiny eyelets on each side of a caterpillar's head. They provide basic light-sensing, but caterpillars have very poor vision compared to adult butterflies.
Imago	The fully developed adult form of an insect, in this case, the butterfly or moth that emerges from the chrysalis after the pupal stage is complete.

An Awesome Explanation of the Life Cycle of a Caterpillar

Different Life Cycle Stages