Picture: Hickory Tussock Moth Caterpillar
Moth caterpillars are the larval stage of moths, and they play a crucial role in the life cycle of these insects. They are primarily focused on growth, consuming large quantities of plant material to build up energy reserves that will sustain them through metamorphosis. Unlike the adult moths, which often focus on reproduction and dispersal, the caterpillar stage is entirely dedicated to feeding and development. Their bodies are usually soft, segmented, and adapted for chewing leaves, though some species have evolved specialized features such as horns, spines, or camouflage patterns.
Some caterpillars are brilliantly colored with bold stripes, spots, or spines, while others are masters of disguise, blending seamlessly into bark, leaves, or twigs. This diversity of form and coloration is closely tied to their survival strategies. Brightly colored individuals often use warning signals to deter predators, as many are toxic or distasteful. In contrast, camouflaged species rely on remaining undetected in their natural habitats.
Their feeding habits can vary widely depending on the species. While many feed on common plants like grasses, trees, or shrubs, others specialize in particular host plants. Some are agricultural pests, capable of causing significant damage to crops, orchards, or ornamental plants, while others have little to no impact on human activities. The choice of host plant is often critical to the caterpillar’s survival, as certain plants provide both food and chemical defenses that protect the caterpillar from predators.
Beyond camouflage and warning coloration, many moth caterpillars have physical adaptations such as hairs, spines, or even stinging bristles that can deliver venom or irritants. These structures discourage birds, mammals, and other predators from feeding on them. Some species also employ behavioral defenses, such as rearing up and displaying false eyespots to mimic snakes or other threatening animals. These strategies collectively help increase their chances of surviving long enough to pupate.
After reaching a certain size, the moth caterpillar stops feeding and finds a safe place to pupate, often creating a cocoon of silk. Inside, its body undergoes complete metamorphosis, reorganizing into the adult moth with wings, reproductive organs, and new sensory systems.
Picture: Tussock Moth Caterpillar
Moth Caterpillars (Caterpillars That Turn Into Moths)
Woolly Bear Caterpillar (Pyrrharctia isabella)
Perhaps the most beloved caterpillar in North America, the Woolly Bear is banded in rusty brown and black, covered in dense, bristly hair that gives it its common name. It is famous in folklore for supposedly predicting the severity of winter based on the width of its brown band — a charming myth with no scientific basis. It feeds on a wide variety of low-growing plants including plantain, dandelion, and clover, and overwinters as a caterpillar, freezing solid and thawing in spring to complete its development. It becomes the Isabella Tiger Moth, a pleasant orange-yellow adult.
Tobacco Hornworm (Manduca sexta)
Large, vivid green, and unmistakable, this caterpillar grows up to ten centimetres long and bears a distinctive red horn at its rear end. It feeds voraciously on tobacco, tomato, and other plants in the nightshade family, and its size and colouration make it a remarkable find in the garden. Despite the fearsome horn, it is entirely harmless to humans. The adult is the Carolina Sphinx Moth, a powerful, fast-flying moth with a wingspan rivalling a hummingbird’s.
Tomato Hornworm (Manduca quinquemaculata)
Nearly identical to its close relative the Tobacco Hornworm, this caterpillar is bright green with seven diagonal white stripes along its sides and a black horn at the tail. It is a notorious pest of tomato and pepper plants. A parasitic wasp (Cotesia congregatus) frequently lays eggs inside it; the white rice-grain-like cocoons attached to infested caterpillars are the emerging wasp pupae, and gardeners are encouraged to leave these parasitised individuals in place.
Cecropia Moth Caterpillar (Hyalophora cecropia)
One of the most spectacular caterpillars in North America, the mature Cecropia larva is a plump, pale green giant studded with rows of vivid blue, yellow, and red knobby tubercles tipped with black bristles. It feeds on a wide range of trees including cherry, apple, and maple. The adult Cecropia Moth is North America’s largest native moth, with wingspans reaching up to seventeen centimetres.
Luna Moth Caterpillar (Actias luna)
Bright, vivid green with rows of small yellow spots along its sides and reddish-orange tubercles, this plump caterpillar feeds on the leaves of walnut, hickory, sweet gum, and birch. It produces a clicking sound when disturbed — a defensive behaviour thought to warn predators. The adult Luna Moth, with its trailing hindwing tails and pale green colouration, is considered one of the most beautiful moths in the world.
Polyphemus Moth Caterpillar (Antheraea polyphemus)
Stout and brilliant green, with a series of raised yellow spots along its sides from which short bristles emerge, this large caterpillar feeds on oak, maple, birch, and many other deciduous trees. It produces a sharp clicking sound when molested and regurgitates an unpleasant fluid as a further defence. The adult is a spectacular russet-brown silk moth bearing striking eyespots on all four wings.
Io Moth Caterpillar (Automeris io)
This caterpillar undergoes a dramatic change in appearance across its instars, starting out orange before transforming into a vivid green with a red and white stripe along each side and clusters of venomous green spines. Those spines are genuinely urticating — contact causes a painful, burning rash. It feeds on corn, clover, redbud, and many other plants, and is found across eastern North America.
Saddleback Caterpillar (Acharia stimulea)
One of the most distinctive — and most dangerous — caterpillars in North America, the Saddleback is named for the vivid green “saddle” patch with a white-edged brown centre on its back. Its body is festooned with long, branching venomous spines capable of inflicting a severe and painful sting. It feeds on a wide variety of trees and shrubs and should never be handled.
Puss Caterpillar (Megalopyge opercularis)
Deceptively adorable in appearance — covered in soft, flowing hair that resembles a tiny cat — the Puss Caterpillar conceals one of the most venomous stings of any caterpillar in the United States. Hidden beneath the silky hairs are sharp, hollow spines connected to venom glands; contact causes intense, radiating pain. It feeds on oak, elm, and rose family plants and becomes the Southern Flannel Moth.
Giant Leopard Moth Caterpillar (Hypercompe scribonia)
Covered in dense, glossy black bristles with bright red bands visible between its segments when it curls into a defensive ball, this striking caterpillar is a familiar garden species across eastern North America. Despite its intimidating appearance, the bristles are harmless. It feeds on a wide range of plants including cherry, dandelion, and plantain, and overwinters as a caterpillar to pupate in spring.
White-marked Tussock Moth Caterpillar (Orgyia leucostigma)
An extraordinary-looking caterpillar with four dense white tussocks of hair on its back like bristle-brushes, long black pencil tufts at its head and tail, and red-spotted flanks. The hairs can cause skin irritation in sensitive individuals. It feeds on a wide range of deciduous trees including apple, elm, and oak, and is found across North America. The adult female is wingless and never leaves her cocoon.
Hickory Horned Devil (Citheronia regalis)
The largest caterpillar found in North America, the Hickory Horned Devil can reach up to fifteen centimetres in length. It is turquoise-green with black-tipped orange and red horns projecting from its thorax — an appearance so fearsome that it is sometimes called the “most terrifying caterpillar.” Despite its dragon-like look, it is entirely harmless. It feeds on walnut, hickory, and sweet gum, and becomes the beautiful Regal Moth.
Banded Woolly Bear (Gynaephora groenlandica)
Found in the extreme Arctic, this remarkable caterpillar holds a record few insects can match: it can live for up to fourteen years, spending most of its life frozen solid in permafrost and feeding only briefly each summer when the tundra thaws. Its dense, dark fur provides insulation against brutal polar conditions. It becomes a small, plain moth that lives for only a few days — purely long enough to reproduce.
Cinnabar Moth Caterpillar (Tyria jacobaeae)
Bold and unmistakable, banded in rings of jet black and bright orange-yellow, this caterpillar advertises its toxicity loudly through its aposematic colouration. It feeds gregariously and voraciously on ragwort, accumulating the plant’s pyrrolizidine alkaloids into its own tissues and retaining them into adulthood. Groups of these caterpillars can completely defoliate ragwort plants, and they are sometimes deliberately introduced as a biocontrol agent.
Garden Tiger Moth Caterpillar (Arctia caja)
A classic “Woolly Bear” type — long-haired, with dense black bristles and a rusty-orange underside — this caterpillar is a familiar and charismatic garden species across Europe and Asia. It feeds on a wide variety of low plants including dock, plantain, and stinging nettle. Its hairs can cause mild irritation and are incorporated into the cocoon as a defensive lining. The adult Garden Tiger Moth is richly patterned in brown, white, orange, and blue.
Six-spot Burnet Moth Caterpillar (Zygaena filipendulae)
Pale yellow-green with rows of black spots, this caterpillar feeds on bird’s-foot trefoil and accumulates hydrogen cyanide from the plant, synthesising additional cyanide of its own. This toxic cocktail is retained through metamorphosis into the striking red-spotted adult moth. It is one of a handful of animals that both sequesters and biosynthesises its own cyanide defences.
Emperor Moth Caterpillar (Saturnia pavonia)
Young larvae are jet black with orange bands, but as they mature, they transform dramatically into a vivid green studded with rings of pink-based tubercles tipped with black spines. This is Britain’s only native member of the silk moth family, feeding on heather, bramble, and hawthorn on moorland and open countryside. The adult male’s feathery antennae can detect the female’s pheromones from several kilometres away.
Pale Tussock Moth Caterpillar (Calliteara pudibunda)
A flamboyant caterpillar with four dense yellow or white tussocks of bristly hair along its back and a single red tail tuft. It feeds on a wide range of deciduous trees including beech, oak, and hop. The hairs can cause skin irritation and are woven into the cocoon for protection. The adult moth is pale and modest in comparison to the theatrical larva.
Oak Eggar Moth Caterpillar (Lasiocampa quercus)
Large, hairy, and dark chocolate-brown with pale bands and a covering of dense, irritating hairs, this substantial caterpillar feeds on heather, bramble, hawthorn, and many other plants. It overwinters as a larva and is commonly seen crossing roads and paths on warm days. The adult moth has no functional mouthparts and does not feed, existing solely to reproduce.
Drinker Moth Caterpillar (Euthrix potatoria)
Named for its habit of drinking dewdrops from grass blades, this large, hairy caterpillar is dark brown with a row of pale blue spots along its sides and a dense covering of long tawny hairs. It feeds on coarse grasses such as cock’s-foot and reed and is often found in damp meadows and marshes. It overwinters as a caterpillar and is one of the larger larvae seen basking in spring sunshine.
Fox Moth Caterpillar (Macrothylacia rubi)
One of the most frequently encountered hairy caterpillars in the British Isles, the Fox Moth caterpillar is deep black with orange-brown bands of hair, most visible when it curls for defence. It feeds on heather, bilberry, and bramble on moorland and heathland. After overwintering, it becomes a rich tawny-brown adult moth whose males fly fast in bright sunshine.
Buff-tip Moth Caterpillar (Phalera bucephala)
Gregarious in early instars, this yellow-and-black banded, hairy caterpillar feeds communally on oak, lime, and hazel, defoliating entire branches before the group disperses to pupate. From a distance, a seething mass of these caterpillars on a branch is an extraordinary sight. The adult moth is a master of camouflage, resembling a broken birch twig.
Lackey Moth Caterpillar (Malacosoma neustria)
Vividly striped in blue, orange, and white, this gregarious caterpillar lives in conspicuous silken tents spun on the branches of hawthorn, blackthorn, and fruit trees. The tent provides protection from predators and morning cold, and the group basks communally on its surface. Large infestations can severely damage hedgerow trees, though populations are kept in check by parasitoid wasps.
Vapourer Moth Caterpillar (Orgyia antiqua)
One of Britain’s most ornate caterpillars, with four dense cream tussocks on its back, long feathery black and red pencil tufts, and red spots along its sides. It feeds on a wide range of trees including oak, rose, and sallow. The caterpillar’s hairs can cause irritation and are incorporated into the cocoon. The adult female is wingless and crawls only a short distance from her cocoon before laying eggs.
Yellow-tail Moth Caterpillar (Euproctis similis)
Black with bold red and white markings and long tufts of hair, this caterpillar feeds on hawthorn, blackthorn, and oak. The hairs are mildly urticating and can cause rashes and eye irritation. The caterpillar overwinters communally in a silken web on the branches of its host plant. The adult female has a distinctive yellow tail tuft used to cover her eggs in a protective layer of hairs.
Brown-tail Moth Caterpillar (Euproctis chrysorrhoea)
Considered a public health concern in parts of the UK and the USA where it has been introduced, this caterpillar’s hairs carry a barbed toxin that causes severe skin rash, respiratory distress, and eye inflammation. It is dark brown with two red spots and feeds communally on hawthorn and fruit trees, spending winter in a communal silken tent. Outbreaks can be significant enough to trigger public health warnings.
Spurge Hawk-moth Caterpillar (Hyles euphorbiarum)
Strikingly coloured in black, red, and yellow-white spots with a prominent red horn at the tail, this large hawk-moth larva feeds exclusively on spurge plants, accumulating their toxic latex. It is found around the Mediterranean and in the Canary Islands, where it is often seen traversing open, stony ground in search of food. The adult is a handsome, fast-flying moth with pink hindwings.
Privet Hawk-moth Caterpillar (Sphinx ligustri)
Britain’s largest resident moth caterpillar, this plump, vivid green larva is decorated with seven diagonal purple-and-white stripes along its sides and bears a distinctive curved black horn at its tail. It feeds on privet, ash, and lilac. Despite its large size, it is surprisingly difficult to spot when resting on a privet hedge. The adult is a beautifully patterned brown and pink hawk-moth.
Eyed Hawk-moth Caterpillar (Smerinthus ocellata)
Pale green with seven diagonal whitish stripes and a blue-tipped horn, this caterpillar rests along the undersides of willow and apple leaves, where its colour and the diagonal striping break up its outline perfectly against the sunlit foliage. When disturbed, it rears its head and makes itself look larger. The adult moth reveals vivid blue eyespots on its hindwings when threatened.
Lime Hawk-moth Caterpillar (Mimas tiliae)
A handsome caterpillar, apple-green with seven yellow diagonal side stripes and a blue horn, it feeds on lime, elm, and alder. As it approaches pupation, it turns a rich purplish-brown before descending from its host tree to burrow into the soil. The adult is a subtly beautiful moth with mottled olive-green and brown wings.
Poplar Hawk-moth Caterpillar (Laothoe populi)
Green and well-camouflaged with yellow diagonal side stripes and a yellow or bluish horn at the tail, this substantial caterpillar feeds on poplar, willow, and aspen. It rests along the midrib of a leaf, where its markings mimic the veining of the leaf surface. The adult Poplar Hawk-moth is Britain’s most common hawk-moth.
Elephant Hawk-moth Caterpillar (Deilephila elpenor)
Named for the trunk-like snout of its early instars, the mature Elephant Hawk-moth caterpillar is brown or green, with four striking pink-ringed false eyespots on its thorax. When alarmed, it retracts its head into its body, causing the eyespots to bulge and mimic the face of a large vertebrate. It feeds on willowherb and bedstraw. The adult moth is a stunning deep pink and olive green.
Hummingbird Hawk-moth Caterpillar (Macroglossum stellatarum)
Green with a yellow stripe along its side and a blue-tipped horn, this caterpillar feeds on bedstraw (Galium) species in open, sunny habitats. It is a strong migratory species, with adult moths famously resembling hummingbirds as they hover before flowers. The caterpillar develops quickly across two or three generations per year in warmer parts of Europe.
Death’s-head Hawk-moth Caterpillar (Acherontia atropos)
The largest hawk-moth caterpillar found in Europe, reaching up to thirteen centimetres. It is yellow or green with diagonal purple and white stripes and a prominently curved yellow horn at its tail. It feeds on potato, deadly nightshade, and other nightshades. The adult moth is famous for the skull-like marking on its thorax and its ability to squeak loudly when handled.
Cinnabar Moth (Tyria jacobaeae)
Boldly patterned in black spots on a creamy-white background with a yellow-orange side stripe, the Magpie Moth caterpillar feeds on gooseberry, currant, hawthorn, and blackthorn. It can be a minor pest in fruit gardens. The adult moth shares the same bold black-and-white “magpie” pattern as the caterpillar, making it one of the few moths where both larva and adult share a visually similar warning appearance.
Herald Moth Caterpillar (Scoliopteryx libatrix)
Slender and bright green with yellow side stripes and a black head, this elegant caterpillar feeds on the leaves of willow and poplar. It moves with a looping action reminiscent of a geometer moth caterpillar. The adult Herald is a richly marked moth with orange and brown wings, one of the few moths that overwinters as an adult, sometimes roosting in caves and cellars.
Old Lady Moth Caterpillar (Mormo maura)
Dark greyish-brown and mottled, this caterpillar is nocturnal and feeds on dock, bramble, and blackthorn. It overwinters as a young larva and completes its feeding in spring. Its sombre, bark-like colouration provides excellent camouflage at rest. The adult Old Lady Moth is named for its dark, sombre wing pattern, said to resemble a Victorian widow’s shawl.
Angle Shades Moth Caterpillar (Phlogophora meticulosa)
Variable in colour from green to brown, this caterpillar has a distinctive pale V-shaped mark along its back in each segment. It feeds on a huge range of plants including nettle, fern, and hop, and is found throughout the year due to the moth’s multiple generations. The adult Angle Shades is instantly recognisable for its beautifully crumpled, leaf-like resting posture.
Common Footman Moth Caterpillar (Eilema lurideola)
Flattened, dark, and covered in fine grey hairs, this caterpillar feeds largely on lichens and algae growing on tree bark and fence posts. It is a slow-growing species that overwinters as a small larva. Its lichen diet makes it an indicator of good air quality. The adult is a narrow, grey moth that rests with its wings wrapped tightly around its body.
Rosy Footman Moth Caterpillar (Miltochrista miniata)
Similar in lifestyle to the Common Footman, this hairy caterpillar also feeds on lichens and algae. It is a small, relatively nondescript larva, but the adult it becomes is charming — bright orange-red with rows of black spots, one of the most attractive small moths of the British woodland edge.
Burnished Brass Caterpillar (Diachrysia chrysitis)
Green with a pale dorsal stripe and a slightly humped back, this caterpillar feeds on stinging nettle and dead-nettle. It moves with a looping gait similar to geometrid caterpillars. The adult Burnished Brass Moth has metallic golden-green patches on its forewings that genuinely glint like polished metal in sunlight.
Silver Y Moth Caterpillar (Autographa gamma)
Bright green and slender with pale lines running the length of its body, this caterpillar feeds on clover, cabbage, nettles, and many other low plants. It is a migrant species, with caterpillars found across Europe and North Africa. Despite its small size, it is one of the most abundant moth caterpillars in Europe. The adult is named for the silver Y-shaped mark on each forewing.
Peppered Moth Caterpillar (Biston betularia)
A masterclass in camouflage, this caterpillar is a stick mimic — long, slender, brown or green, and capable of holding its body rigid and at an angle from a twig to pass as a broken branch or twig. It feeds on birch, oak, and many other trees. The adult Peppered Moth is famous for its role in demonstrating natural selection: the melanic (dark) form increased during industrial pollution and declined as air quality improved.
Winter Moth Caterpillar (Operophtera brumata)
A small, bright green looper caterpillar that feeds on the young leaves of oak, apple, sycamore, and many other trees. It moves by “looping” — drawing its rear legs up to its forelegs and then extending its body forward. It feeds in early spring, exploiting the brief window when young leaves are soft and before other caterpillars have emerged in force. The adult female is wingless.
Bogong Moth Caterpillar (Agrotis infusa)
Dark brown to grey and smooth, this cutworm-type caterpillar feeds nocturnally on agricultural plants including clovers and pasture grasses across southern Australia. It is the larva of the Bogong Moth, celebrated in Australian Aboriginal culture as a vital seasonal food source. After pupation, adult moths undertake a remarkable mass migration of up to a thousand kilometres to aestivate in the cool caves of the Australian Alps, where they were historically harvested in their millions.