Short answer
Metamorphosis is the overall developmental transformation from immature insect stages to the adult. Molting is a specific shedding of the old exoskeleton. An insect may molt repeatedly while growing through nymph or larval stages; not every molt completes metamorphosis. 1 2
Molts can be steps within metamorphosis, but the terms name different levels of change.
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At a glance
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| Question | Metamorphosis | Molting |
|---|---|---|
| Scale | Life-cycle transformation | One shedding event |
| What changes | Stage, body form and often behavior | Outer covering, sometimes accompanying stage change |
| Can repeat? | One developmental sequence per individual | Usually multiple times before adulthood |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Metamorphosis. The developmental change through which an insect passes from immature stages to an adult form. 1
Molting. Shedding an old outer covering so an arthropod can grow or change stage. 2
Key differences
The insect exoskeleton does not stretch indefinitely, so growth involves shedding it. In complete metamorphosis, larval growth, pupation and adult emergence are parts of the larger transformation. In incomplete metamorphosis, successive nymph molts gradually reveal adult features. 1 2
How to tell them apart
If the observation is an insect casting off a skin, call that a molt. If the question concerns the whole change from egg through juvenile stages to adult, call it metamorphosis. A single shed skin does not reveal the entire life history. 1 2
Where they overlap
A molt can coincide with a dramatic transition, including the final emergence of an adult. Both terms help explain why a juvenile insect can look unlike its later self. 1 2
Edge cases
Molting is also used for other animals, including birds shedding feathers; metamorphosis applies beyond insects, such as amphibians. This article focuses on insect exoskeletons and insect life cycles. 1 2
Why the distinction exists
Separating an event from a developmental process makes life-cycle descriptions precise and helps identify the stage seen in the field. 1 2
Common misconceptions
A caterpillar does not become a butterfly at every molt. Repeated molts mostly allow growth before later developmental transitions. 1 2
Examples
A grasshopper nymph sheds its exoskeleton several times. Its progression from egg through nymphs to adult is incomplete metamorphosis. 1 2
Sources
Sources checked October 3, 2026.
- Purdue Extension — Understanding Insect Metamorphosis. Complete and incomplete metamorphosis.
- Penn State Extension — Morphing with Bugs. Life cycles and molting.