L
Species Profile

Luna Moth Caterpillar

Actias luna

Eat leaves, spin silk, become moonlight
Leigh Prather/Shutterstock.com

Luna Moth Caterpillar Distribution

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Found in 45 states/provinces

a bright green luna moth caterpillar against white isolate. The caterpillar is segmented with evenly spaced grange dots on each segment. The caterpillar is on a twig.

At a Glance

Wild Species
Also Known As Luna caterpillar, American moon moth, American moon moth caterpillar, Moon moth, Moon moth caterpillar
Diet Folivore
Activity Nocturnal
Lifespan 28 years
Status Not Evaluated
Did You Know?

A full-grown Actias luna caterpillar reaches about 70 mm (7 cm) long before pupating.

Scientific Classification

The luna moth caterpillar is the larval form of Actias luna, a North American giant silk moth (family Saturniidae). The caterpillar is a leaf-eating stage that later spins a silk cocoon and pupates before emerging as the distinctive pale-green adult luna moth.

Kingdom
Animalia
Phylum
Arthropoda
Class
Insecta
Order
Lepidoptera
Family
Saturniidae
Genus
Actias
Species
Actias luna

Distinguishing Features

  • Bright green, cylindrical caterpillar typical of saturniids
  • Rows of small raised bumps (tubercles) often with tiny bristles
  • Feeds on leaves of various deciduous trees/shrubs depending on region
  • Spins a silk cocoon among leaves/litter before pupation

Physical Measurements

Length
3 in (2 in – 3 in)

Appearance

Primary Colors
Secondary Colors
Skin Type Soft-bodied caterpillar with smooth-to-finely granular cuticle, short sparse setae, and low rounded tubercles (non-urticating).
Distinctive Features
  • Final (5th) instar typically ~55-70 mm long; robust, cylindrical saturniid larva (Wagner 2005; Tuskes et al. 1996).
  • Usually 5 instars; overall larval development commonly ~3-4 weeks in warm-season broods (Tuskes et al. 1996).
  • Bright green body with a thin yellow lateral line; lacks the large multicolored knobs of Hyalophora (e.g., cecropia) larvae.
  • Tubercles are low and evenly spaced; not a medically significant stinging caterpillar (no venomous spines).
  • Feeds on deciduous trees in eastern North America; commonly recorded hosts include hickories (Carya), walnuts (Juglans), sweetgum (Liquidambar), birches (Betula), persimmon (Diospyros), and sumacs (Rhus) (Wagner 2005; Tuskes et al. 1996).
  • Typically rests along leaf midribs/petioles; when disturbed may drop or hang by silk and curl defensively (general Saturniidae larval behavior; Wagner 2005).
  • Spins a tough silk cocoon among fallen leaves/leaf litter; pupates inside and may overwinter as a pupa in much of its range (Tuskes et al. 1996).

Did You Know?

A full-grown Actias luna caterpillar reaches about 70 mm (7 cm) long before pupating.

It passes through 5 larval instars (growth stages), molting between each one.

It can make an audible "click" with its mandibles when disturbed-common in giant silk moth (Saturniidae) larvae.

Pupation happens inside a silk cocoon typically spun among fallen leaves, often incorporating a leaf into the cocoon wall.

In much of the North, it overwinters as a pupa; in warmer parts of its range it can have 2 generations per year.

Its host-plant menu is broad for a saturniid, including birch (Betula), hickory (Carya), walnut (Juglans), sweetgum (Liquidambar), persimmon (Diospyros), and sumac (Rhus), among others.

Unique Adaptations

  • Camouflage coloration: a smooth, bright green body with a pale lateral line and small colored tubercles helps it visually merge with fresh foliage while breaking up its outline.
  • Silk engineering for concealment: the cocoon is commonly spun with leaf material incorporated, creating a tough, cryptic "leaf package" that matches forest-floor litter.
  • Digestive specialization for woody hosts: like other saturniid larvae, it efficiently processes tough tree leaves using strong mandibles and a high-throughput gut-enabling rapid growth to ~7 cm in weeks.
  • Predator deterrence without stinging spines: unlike some spiny caterpillars, A. luna relies on startle behaviors (clicking/rearing), regurgitation, and hiding rather than urticating hairs.
  • Saturniidae life-history strategy: the larval stage is the primary feeding and energy-storage phase; the adult moth does not feed, so larval fat reserves must support metamorphosis and adult reproduction.

Interesting Behaviors

  • Nocturnal-leaning feeding: larvae commonly feed more actively in evening/night and rest along leaf midribs or stems by day, relying on camouflage.
  • Defensive display and sound: when handled or threatened, larvae may rear back, click their mandibles, and sometimes regurgitate as a deterrent (a widespread Saturniidae tactic).
  • Edge-feeding pattern: they often chew from leaf margins inward; older instars can defoliate small branches on favored host plants.
  • Leaf-litter pupation choice: mature larvae leave the feeding site to seek sheltered ground litter, where they spin a cocoon that blends into dead leaves-reducing visibility to predators.
  • Season-timed development: in northern areas the larva's end-of-season pupation leads to diapause (a resting state) through winter; in southern areas development may continue to a second brood.

Cultural Significance

The Luna moth caterpillar (Actias luna) is used in classrooms and nature centers to teach full metamorphosis and forest food webs. The name "luna" (moon) links its life cycle to night, seasons, and change in art and stories.

Myths & Legends

The name 'luna' in Luna moth (Actias luna) comes from Latin for 'moon.' It refers to the moth's night habits and pale, moonlike color, shaping how people see its whole life cycle.

In modern North America, people often see the luna moth (Actias luna) as a sign of change or new starts; its caterpillar and cocoon are seen as the 'work' and 'waiting' before change.

In 18th–19th century North America and Europe, luna moths (Actias luna) were prized showy specimens. Early collectors reared caterpillars on host branches to get perfect adults, a historical tradition.

Conservation Status

NE Not Evaluated

Has not yet been evaluated against the criteria.

Population Unknown

Life Cycle

Birth 200 caterpillars
Lifespan 28 years

Lifespan

In the Wild
21–35 years
In Captivity
20–40 years

Reproduction

Mating System Polygyny
Social Structure Transient
Breeding Pattern Transient
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Larvae do not mate; reproduction occurs in short-lived adults (~7-10 days). Nocturnal females "call" with a sex pheromone to attract males; internal copulation commonly lasts ~6-8 hours, with females typically mating once while males may mate multiple times.

Behavior & Ecology

Social Solitary Group: 1
Activity Nocturnal
Diet Folivore Sweetgum (Liquidambar styraciflua) leaves
Seasonal Hibernates

Temperament

Generally non-aggressive and non-territorial; avoids conflict by spacing out on foliage.
Primarily a sit-and-feed leaf-browser; rests motionless between feeding bouts (Wagner 2005).
Defensive responses include freezing, thrashing, and dropping on silk when disturbed (Wagner 2005).
Most larvae occur singly; locally higher densities happen when females lay multiple eggs on the same tree.
Larval development typically 20-30 days across five instars under favorable conditions (Tuskes et al. 1996).

Communication

None documented; larvae lack true vocalization structures Wagner 2005
Tactile contact during incidental encounters; no cooperative foraging or coordinated group movement.
Chemical cues likely via frass/cuticular compounds for predator deterrence rather than social signaling.
Silk use for anchoring and escape-dropping; not used for trail recruitment Wagner 2005

Habitat

Biomes:
Temperate Forest Boreal Forest (Taiga)
Terrain:
Mountainous Hilly Plains Valley Riverine Coastal
Elevation: Up to 4921 ft 3 in

Ecological Role

Folivorous primary consumer (herbivore) in North American deciduous and mixed forests; also an important prey/host resource for predators and parasitoids during the larval stage.

Transfers plant biomass to higher trophic levels (food for insectivorous birds, small mammals, predatory insects) Supports parasitoid wasps/flies as a host (contributing to parasitoid biodiversity and food webs) Nutrient cycling via frass deposition and through cocoon/pupal remains in leaf litter Influences host-plant leaf area and patterns of herbivory at local scales

Diet Details

Other Foods:
Sweetgum leaves Hickory leaves Walnut leaves Persimmon leaves White birch leaves Sumac leaves Alder leaves Willow leaves +2

Human Interaction

Domestication Status

Wild

Actias luna (luna moth) is a wild North American moth with no domestication history. People do not breed it for silk. People mostly watch it, rear it in classrooms or museums, or breed it as a hobby. It appears in citizen science and in work on light pollution and conservation.

Danger Level

Low
  • No medically significant venom or stinging apparatus known for Actias luna larvae; they are not considered hazardous like some urticating saturniid larvae (risk is primarily misidentification with other species).
  • Minor risk of skin irritation or allergy from handling (general insect-allergen exposure), especially in sensitive individuals.
  • Indirect risk: if wild-collected, larvae can carry parasitoids or pathogens that may affect other captive insects; standard hygiene and avoiding release of captive stock reduces ecological/health risks.

As a Pet

Suitable as Pet

Legality: Usually legal to keep and raise Luna Moth (Actias luna) caterpillars if locally collected, but parks may ban collecting, moving live moths across borders may need permits, and some places forbid releasing captive insects. Check local rules.

Care Level: Moderate

Purchase Cost: $10 - $60
Lifetime Cost: $25 - $150

Economic Value

Uses:
Education/outreach Hobbyist breeding and live-insect trade Ecotourism/citizen science and nature photography Scientific research (development, physiology, ecology) Craft/ornamental use of cocoons (minor)
Products:
  • live eggs/larvae/pupae sold by hobby breeders (small-scale)
  • classroom rearing kits/materials (small-scale)
  • display specimens for educational collections (regulated/ethical sourcing varies)
  • cocoons used in crafts/ornamentation (minor, not a commercial silk fiber industry)

Relationships

Predators 10

Paper wasp
Paper wasp Polistes
Yellowjackets
Yellowjackets Vespula
Chinese mantis Tenodera sinensis
Blue jay
Blue jay Cyanocitta cristata
American robin
American robin Turdus migratorius
Black-capped chickadee
Black-capped chickadee Poecile atricapillus
White-footed mouse Peromyscus leucopus
Tachinid flies Tachinidae
Tachinid fly Compsilura concinnata
Ichneumon wasps Ichneumonidae

Related Species 6

Indian moon moth Actias selene Shared Genus
Chinese moon moth Actias dubernardi Shared Genus
Japanese moon moth Actias maenas Shared Genus
Polyphemus moth
Polyphemus moth Antheraea polyphemus Shared Family
Cecropia moth
Cecropia moth Hyalophora cecropia Shared Family
Promethea silkmoth Callosamia promethea Shared Family

The luna moth caterpillar (Actias luna), is the larval stage of the luna moth, a large green moth found in North America. The caterpillars have a waffle-iron-like texture to their segmented bodies, which are green with tiny orange dots on the raised squares. Sparse bristly hairs cover their bodies. They feed on a variety of trees, growing to be around 2-2.5 inches in length before entering the pupal stage. The luna moth caterpillars are typically active during the spring and summer and will spin a cocoon made of silk and leaves in which to pupate. Keep reading to learn more about Actias luna.

Five Frank Facts about Luna Moth Caterpillars

  • Luna moth caterpillars are the larval stage of the luna moth, a large green moth found in North America.
  • They feed on a variety of trees, including walnut, hickory, and persimmon.
  • Luna moth caterpillars grow to be around 2-2.5 inches in length before entering the pupal stage.
  • They are typically active during the spring and summer months.
  • They spin a cocoon made of silk and leaves in which to pupate.

Luna Moth Caterpillar: Scientific Name

The scientific name for the luna moth caterpillar is Actias luna. The caterpillar shares its name with its adult form, the luna moth. Its Latin name translates to active moon. And while it’s true that as adult moths they are most active at night, luna moth caterpillars are actually diurnal. However, the luna moth gets its name from the moon-like spots on its hindwings. The family name Saturniidae refers to the false eyes or eyespots of concentric rings, that resemble the rings of the planet Saturn.

Appearance

A luna moth caterpillar is typically bright green with a series of small orange spots dotting the length of its textured body. It has a pair of black, triangular-shaped markings on its back near the head, as well as a pair of orange or reddish-orange spots near the tail. The body is also covered in short, fine hairs. It typically grows to be 2-2.5 inches long. The weight of a luna moth caterpillar can vary depending on the individual and the stage of its development. However, generally speaking, a luna moth caterpillar weighs between 0.03 – 0.105 ounces.

A bright green Luna Moth caterpillar crawling up green leaf. The caterpillar is vertical in the frame.

A luna moth caterpillar is typically bright green with a series of small orange spots dotting the length of its textured body.

Luna Moth Caterpillar: Behavior

Luna moth caterpillars are primarily active during the daytime, feeding on the leaves of trees and plants. They are relatively slow-moving and do not have the ability to sting or bite. They are also solitary creatures and do not form colonies or congregate in large groups. As they get closer to pupating, they will stop eating and look for a place to spin their cocoon.

Habitat / Diet

These caterpillars can be found in many different types of forest habitats in North America. They live in deciduous woods, hardwood bottoms, and pine-hardwood forests. They are also found in gardens and backyards where host plants are about. These caterpillars prefer trees such as hickory, walnut, and sweetgum. The leaves of these trees are the main food source for the caterpillars. They also can be found on cherry, plum, and apple trees. Their lives are spent feeding on the leaves of the host tree, although they will move to other trees to find food or to pupate.

Predators

Luna moth caterpillars have a variety of predators, including:

  • Birds: Many species of birds, such as robins, blue jays, and woodpeckers, will eat luna moth caterpillars.
  • Wasps: Wasps such as paper wasps and yellow jackets are predators. Paper wasps are parasites. They lay their eggs in the caterpillars, which then hatch and use the caterpillar as a source of food, killing it.
  • Spiders: Several species of spiders including orb-weavers and jumping spiders will prey on luna moth caterpillars.
  • Beetles: Ground beetles and ladybugs will eat them.
  • Other insects: Many types of insects such as ants, lacewings, and stinkbugs are other known predators.
  • Some small mammals like shrews and chipmunks are also known to feed on them.
  • It is worth noting that luna moths also have natural predators like bats, which feed on adult luna moths during their short life.

Threats

Luna moth caterpillars face a variety of threats in their natural habitats. Some of the main threats they face include:

  • Habitat loss: The conversion of natural habitats to developed areas, such as urbanization and agriculture, reduces the availability of suitable trees for luna moth caterpillars to feed on and also reduces the number of trees for adult luna moths to lay their eggs on.
  • Pesticides/herbicides: The use of pesticides and herbicides kills luna moth caterpillars. Pesticides can kill them directly by exposing the caterpillars to toxins. Herbicides can affect their viability by killing the plants they feed on.
  • Climate change: Climate change affects the distribution, abundance, and timing of luna moth caterpillars and their host plants, ultimately affecting the population of the species.
  • Light pollution: Adult luna moths are attracted to lights, which can lead them to fly into buildings or other man-made structures, leading to injury or death.
  • Collection: Some individuals may collect luna moth caterpillars as pets or for observation, which disrupts the population and the ecosystem in which they live.
  • Other human activities such as logging, mining, and oil and gas drilling also have a negative impact on the habitat of luna moths, and their caterpillars.
  • Overall, the population of luna moths has been in decline, and conservation efforts are needed to protect and preserve their habitats, as well as to raise awareness of the importance of these insects.

Conservation Status

Though the conservation status of individual species is bestowed on the adult form which is responsible for reproduction, the luna moth caterpillar, like its adult form, is not considered to be a threatened or endangered species and does not have a designated conservation status. However, like many other moth and butterfly species, luna moths may be at risk due to habitat destruction and pesticide use.

Lifecycle/Lifespan

The luna moth caterpillar goes through four stages in its lifecycle: egg, larva, pupa, and adult.
Female luna moths lay their eggs on the leaves of trees and shrubs that are preferred food sources for the caterpillars, such as hickory, walnut, and sweetgum. The eggs are small, round, and green in color. They hatch in about a week. After the eggs hatch, the caterpillars begin to feed on the leaves of the host plant. They go through several molts (also called instars or shedding) of their exoskeleton, as they grow. During this stage, they are green in color and can grow up to 2.5 inches long. When the caterpillar has reached its full size, it begins to turn brown. Next, it will stop eating and spin a cocoon, entering the pupal stage. The pupa is brown and about 1.5 inches long. It will stay in the cocoon for about two weeks before emerging as a luna moth.
Luna moths are large, beautiful insects with translucent green wings.

The lifespan of a luna moth caterpillar is approximately one month. The lifespan of the luna moth is much shorter, at about 1 week.

Two Luna Moth caterpillars are visible on a green leaf. The caterpillar in the top part of the frame is green with tiny orange dots. The caterpillar beneath it is brown are preparing to pupate.

When the caterpillar has reached its full size, it begins to turn brown.

Population

The population of luna moth caterpillars is not specifically tracked and there are no exact numbers available. The luna moth, like many other species of moths and butterflies, can fluctuate in population size depending on a variety of factors such as habitat loss, disease, weather, predation, and pesticide use. While the luna moth is not considered to be threatened or endangered, the population is declining in some areas.

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Sources

  1. fllt.org / Accessed January 22, 2023
  2. iucnredlist.org / Accessed January 22, 2023
  3. wikipedia.org / Accessed January 22, 2023
Kathryn Koehler

About the Author

Kathryn Koehler

Kathryn Koehler is a writer at A-Z-Animals where her focus is on unusual animals, places, and events. Kat has over 20 years of experience as a professional writer and educator. She holds a master's degree from Vanderbilt University. When she is not writing for A-Z-Animals, Kat enjoys puttering in her garden, baking deliciously healthful treats for her family, and playing with her two rescue mutts, Popcorn and Scooter. She resides in Tennessee.

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Luna Moth Caterpillar FAQs (Frequently Asked Questions)

A luna moth caterpillar is typically bright green with a series of small orange spots dotting the length of its textured body. It has a pair of black, triangular-shaped markings on its back near the head, as well as a pair of orange or reddish-orange spots near the tail. The body is also covered in short, fine hairs. It typically grows to be 2-2.5 inches long.