A moth’s life cycle has four stages: egg, caterpillar (larva), pupa and adult. The caterpillar does all the eating and growing, the pupa rebuilds its body into a moth, and the adult lives mainly to mate and lay eggs. Most adult moths live only about a week. The whole cycle takes anywhere from a few weeks to more than a year, depending on the species and temperature.
| Stage | What happens | Typical length |
|---|---|---|
| Egg | Laid on or near the larva’s food: leaves for most moths, wool or stored food for household moths | About 4 to 10 days in warm weather |
| Larva (caterpillar) | Eats and grows, shedding its skin several times | A few weeks to months; over 2 years for some clothes moths |
| Pupa | Body is broken down and rebuilt into an adult, often inside a silk cocoon | Usually 10 to 28 days; all winter in some species |
| Adult | Mates and lays eggs; many species don’t feed at all | About a week for most moths |
Table of Contents
Stage 1: Egg
After mating, the female lays her eggs on or near the food her caterpillars will need. Outdoor moths choose the host plant. Household moths choose wool, fur, flour, grains or pet food. Clothes moth females lay about 40 to 50 eggs and die soon after. Indian meal moth females lay 200 to 300 eggs. In warm weather, eggs typically hatch in about 4 to 10 days.
Stage 2: Larva (Caterpillar)
The caterpillar is an eating machine. It grows fast, and because its outer skin doesn’t stretch, it molts several times. Each stage between molts is called an instar. The appetite can be extreme: the polyphemus moth caterpillar holds the Guinness World Record for eating an amount equal to 86,000 times its birth weight in its first 56 days.
How long the larval stage lasts depends on the species, temperature and food. Indian meal moth larvae feed for about 6 to 8 weeks. Clothes moth larvae can take anywhere from 35 days to 2.5 years, molting up to 45 times. This is the only stage that damages clothing and food. Adult moths don’t eat fabric.
Stage 3: Pupa
When it is fully grown, the caterpillar looks for a sheltered spot and turns into a pupa. Many moths spin a silk cocoon first. Others, such as sphinx moths, pupate bare in the soil. A butterfly pupa without a cocoon is usually called a chrysalis.
The pupa looks inactive, but inside it the caterpillar’s body breaks down and is reorganized into wings, legs, antennae and reproductive organs. Moths usually emerge 10 to 28 days after pupating. Giant silkworm moths such as the luna moth spend the whole winter as pupae and emerge in spring.
Stage 4: Adult Moth
A newly emerged moth has soft, crumpled wings. It pumps fluid into the wing veins to expand them, and needs a few hours before it can fly. From then on, its main job is to find a mate.
Most adult moths live only about a week. Some, like the luna moth and other giant silkworm moths, have reduced or missing mouthparts and never eat as adults. They live on fat stored from the caterpillar stage. A few species live longer by spending winter as adults, hidden in cracks and crevices.
How Moths Survive Winter
Each species overwinters in one particular stage:
- As eggs, which hatch when leaves appear in spring
- As caterpillars, which feed on warm days and go dormant in cold weather
- As pupae, like giant silkworm moths in cocoons and sphinx moths in the soil
- As adults, sheltering in cracks, bark or buildings
Some species have 2 or 3 generations a year, others only one, and a few take several years to complete a cycle. In heated homes, household moths keep breeding through the winter.
Life Cycle of Household Moths
| Stage | Clothes moth | Indian meal moth (pantry moth) |
|---|---|---|
| Eggs | 40 to 50 per female; hatch in 4 to 10 days | 200 to 300 per female; hatch in about a week |
| Larva | 35 days to 2.5 years; eats wool, fur, silk, feathers | About 6 to 8 weeks; eats grains, flour, nuts, dried fruit, pet food |
| Pupa | 8 to 10 days in summer, 3 to 4 weeks in winter | About 15 to 20 days |
| Egg to egg | About 4 to 6 months; about 2 generations a year | Several generations a year indoors |
Breaking the cycle means removing the larvae, not just catching adults. See clothes moths, pantry moths and where house moths come from. For more species, see types of moths.
FAQ
Egg, larva (caterpillar), pupa and adult. This is called complete metamorphosis. The caterpillar does all the eating and growing, the pupa is where its body is rebuilt into a moth, and the adult’s job is to mate and lay eggs.
Most moths live only about a week as adults. Some, like the luna moth, have no working mouthparts and can’t eat as adults. The whole life cycle, from egg to adult, can take a few weeks to more than a year depending on the species and temperature.
The adult clothes moth lives only a few weeks, and females die soon after laying 40 to 50 eggs. The larva, the stage that eats wool, can last from about 35 days to 2.5 years, which is why infestations last so long.
Many moth caterpillars spin a silk cocoon and pupate inside it. Others pupate bare in the soil, like sphinx moths. “Chrysalis” is the term usually used for a butterfly pupa, which has no silk cocoon around it.
From a couple of weeks to several months in most species, and longer in some. Indian meal moth larvae feed for about 6 to 8 weeks, while clothes moth larvae can feed for over 2 years in cool conditions.
Sources
- Mississippi State University Extension: The Gloworm, moth life cycles
- University of California IPM: Clothes moths
- Clemson University HGIC: Indian meal moth
- Guinness World Records: Greediest animal (polyphemus moth larva)