Written by Kathryn Koehler
Published: March 23, 2023
Image Credit ©


A cocoon is a protective covering spun or constructed by certain types of animals during their larval or pupal stages, or as adults to protect their eggs. They protect the developing animal from predators and weather-related environmental conditions. Once the animal has metamorphosed inside, it will emerge as an adult ready to mate and reproduce. Discover the difference between a cocoon and a chrysalis here.

What Animals Fashion Cocoons?

A variety of animals, primarily insects, construct cocoons, typically during their larval stage. Bees, beetles, fleas, flies, leeches, moths, wasps, and worms all construct them. Most are fashioned of silk which is secreted from specialized glands that vary across species. Fibroin, a protein comprises most of the silk.


There are over 160,000 species of moths worldwide. Their life cycles and behaviors vary widely depending on the specific species. However, the majority of moth species metamorphose into their adult forms inside cocoons.

A silkworm moth emerging from its cocoon. The silkworm moth is in the left frame. It is mostly white. The cocoon is in the right frame/ It is yellow and cylindrical.
A silkworm moth emerging from its cocoon.



Some species of parasitic wasps (Braconid) lay their eggs in the bodies of other insects. After consuming the host larvae, the wasp larvae then spin cocoons. They are typically small, white, and papery. Braconidae produces ones that resemble grains of rice in shape and size, often elongated and tapered at one end. They may be white or pale in color.

Lepidopteran larvae are parasitized by Hymenoptera parasitic wasps, and the mature parasitoid larvae burrow out of the body to pupate into a white cocoon
The cocoons of parasitic wasps are typically small, white, and papery.

©Pharisee Lee/

Glyptapanteles wasp larvae manipulate the behavior of their caterpillar hosts, essentially turning them into zombie-like bodyguards that protect the wasp pupae from predators. The caterpillar ultimately dies from the consumption of its body fluids by the wasp larvae.

Flea Cocoons

Fleas (Ctenocephalide) construct silken cocoons including the cat flea (Ctenocephalides felis), the dog flea (Ctenocephalides canis), and the human (house) flea (Pulex irritans). The larvae of these flea species spin silken cocoons in which they pupate and develop into adult fleas. Particles of debris and the host’s fur often cover the cocoon which helps to camouflage and protect it. Once the pupa has fully developed, the adult flea emerges and seeks a host on which to feed and reproduce.

lice on dog
the adult flea emerges from the cocoon and seeks a host on which to feed and reproduce.

©Vera Larina/

Fly Cocoons

Flies including caddisflies and lacewings are spinners.


Caddisfly (Trichoptera) cocoons are constructed from silk, which is produced by the larva. Sand, stones, twigs, or shells reinforce the silk, The appearance can vary widely depending on the species of caddisfly and the materials available in the environment.
Some caddisfly larvae construct their cocoons in a cylindrical or conical shape, while others are flat or oval-shaped. Some species of caddisflies even construct elaborate structures that resemble tiny houses or snail shells. Silk threads attach the larvae to rocks or vegetation underwater. The cocoon protects the larva from predators and provides a stable environment for its development into an adult. Once the larva has completed its development, it emerges as an adult caddisfly. In some species, the adult caddisfly will even use the silk from its larval stage to construct a protective case for itself as it continues its life cycle.

Four aggregate caddisfly cocoon are visible center frame on a rock. Three of the cocoon are adjacent, touching each other in a short row. One cocoon is separated from the others. The rock they are on acts as camouflage.
The silk of the caddisfly’s cocoon is often reinforced with materials such as sand, stones, twigs, or shells.

©Evgeni Romanov/


Lacewing (Neuroptera) cocoons are constructed from silk produced by the larvae. The silk is often reinforced with debris such as soil particles, plant fragments, or even the remains of their prey. The resulting structure is usually oval or elliptical and brown or green or white in color, depending on the materials used in its construction. Lacewing cocoons are typically attached to the undersides of leaves or to other surfaces. Once the larvae have completed their development, they emerge as adult lacewings.

A white open cocoon is visible in right center frame. It is the cocoon of a green lacewing. The cocoon is nestled in a dead/dried seed pod. The seed pod is mostly black with brown accents. The pod consists of many individual empty seed hulls.
Lacewing cocoons are typically attached to the undersides of leaves or to other surfaces using silk threads.

©Henri Koskinen/

Bee Cocoons

Some species of Megachilidae, such as mason bees (Osmia), and Apidae such as orchid bees (Euglossini) spin cocoons during their pupal stage. These are made of silk and are used to protect the developing bee inside.

A cluster of mason bee cocoons of different species being held in a light-skinned upturned palm
A cluster of mason bee (Osmia) cocoons.

©M Huston/


Jewel beetle larvae (Buprestidae) spin cocoons from silk. Ground beetles (Carabidae) and desert beetles (Parastizopus armaticeps) create protective pupal chambers or cells underground. Their larvae spin their cocoons within these chambers which offer an extra layer of protection from predators and the elements. Lady beetles (Coccinellidae) spend approximately two weeks metamorphosing prior to emerging.

An Asian Lady Beetle hatching from a cocoon on a tree leaf during Springtime in Houston, TX. The emerging  beetle looks like a kernel of corn - with for brown dots. It is n a green leaf.
Lady beetles (Coccinellidae) spend approximately two weeks metamorphosing inside a silk cocoon prior to emerging.

©Brett Hondow/


Some species of earthworms spin cocoons made of a mixture of soil particles and mucus that the worm secretes. The earthworm lays its eggs inside. The structure protects the eggs and developing embryos until they hatch. The baby earthworms that emerge from the cocoon will grow and develop over time, eventually reaching maturity and producing their own cocoons.

15 little round orangy/yellow spheres.arthworm cocoons on dirt surface
Some earthworms spin cocoons made of a mixture of soil particles and mucus that the worm secretes.

©Torsten Rempt/

Leech Cocoons

Leeches (Clitellata) build cocoons. Glossiphoniid leeches are freshwater leeches are found in various parts of the world, including North America, Europe, and Asia. Some common examples of glossiphoniid leeches that spin include the European medicinal leech (Hirudo medicinalis) and the freshwater leech/North American medicinal leech (Macrobdella decora).

Leech cocoons and baby leeches. The cocoon looks like a cross between honeycomb and a loofa sponge.
Glossiphoniid leeches that build cocoons include the European medicinal leech (Hirudo medicinalis) and the freshwater leech (Macrobdella decora).

©279photo Studio/

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About the Author

Hi! I'm Kat, and my favorite animals are river otters and goldfinches. Baking, gardening, and sewing are my favorite pastimes. I live with two people and two dogs.