The NHBS Guide to UK Caterpillar Identification

Caterpillars are part of the life cycle of moths or butterflies which is known as complete metamorphosis. This life cycle includes four stages: egg, caterpillar (also known as the larval or feeding stage), pupa (the transition stage) and adult (the reproductive phase). With over 2,600 species of moth and 60 species of butterfly in the British Isles, there are a large variety of caterpillars present in our countryside.

There are several stages of caterpillar growth called instars, during which the caterpillar sheds its skin as it grows. Colouration, size and patternation can vary between these instars. Additionally, species can have different variations of caterpillars, including different colour forms. Several species are listed below, grouped by key characteristics such as colour, patternation and features.

Hairy caterpillars

There are many ecological functions of hair-like structures on caterpillars including defence and camouflage. These hairs, called setea, can be almost invisible to the naked eye, while others make them easier to see. Two types of caterpillar hair can cause harm to humans and pets: urticating, which are itchy, non-venomous hairs that can irritate the skin, and stinging hairs, which are hollow spines that have poison-secreting cells that can cause a range of health issues if they enter the skin.  

 

A black, yellow and red spotted caterpillar with several tufts of orange and brown hair
Image by Kjetil Fjelleim via Flickr

Knot Grass moth (Acronicta rumicis): Colour can vary between light gingery brown to near black, with patches of rusty brown hair and a broken line of white dorsal patches. They also have a wavy white line on their sides, broken with bright orange/red spots. They grow up to 40mm in length. Can be confused with the caterpillars of Brown-tail and Yellow-tail moths. Foodplants include Knot Grass as well as Broad-leaved Dock, plantains, Bramble, Hawthorn, Common Sorrel, heather, and Purple Loosestrife.

 

A fluffy black caterpillar with orange stripes
Image by Gail Hampshire via Flickr

Fox Moth (Macrothylacia rubi): Very hairy, up to 70mm long, dark brown with an orangey stripe down the length of its body. Caterpillars in earlier stages of development may have distinctive orange or yellow bands. Commonly feeds on heathers, Bilberry, Creeping Willow, Bramble, Meadowsweet and Salad Burnet.

 

a caterpillar on a leaf. It is very fluffy with long black hairs on top and shorter orange hairs on its underside
Image by Dean Morley via Flickr

Garden Tiger moth (Arctia caja): Also known as the woolly bear caterpillar due its very long hairs. Grows up to 55mm long and has a dark red dorsal area with white tipped hairs,an orangey red underside, and small white markings along its sides. Feeds on a variety of herbacious and garden plants including Common Nettle, Broad-leaved Dock, burdocks and Hound’s-tongue. 

 

A dark brown caterpillar with long, spiking hairs and white and orange parallel patches running along its back
Image by Chris Cooper via Flickr

Brown-tail moth (Euproctis chrysorrhoea): Can measure up to 30mm long, black with white markings down its sides and two distinctive orangey red ‘warts’ on its back near its tail. Be aware that its hairs are toxic to humans. Feeds on plants in the Rosaceae family including Hawthorn, Blackthorn, Plum, Cherry, Rose and Bramble.

 

A large grey caterpillar covered in long white wispy hairs
Image by Janet Graham via Flickr

Miller moth (Acronicta leporina): Up to 35mm long with very long white or yellow hairs that swirl to one side. The body is often a pale green to brown depending on the development stage but this can be hard to see under the hairs. Usually found on birch or Alder trees. 

 

A lime green moth with tufted white bristly hair
Image by gailhampshire via Flickr

Pale Tussock moth (Calliteara pudibunda): Greenish yellow hairs with a black body showing through in bands between tufts. The hairs can vary in colour and can be white, brown or pink. They also have a tail tuft that varies in colour but is usually brown, pink or red. This can be absent in some individuals. The four, tussocky tufts on their dorsal are frequently white, brown or yellow. Feeds on a variety of broadleaved trees and shrubs including Hawthorn, Blackthorn, Crab Apple, oaks, birches and Hazel.

 

A yellow fluffy moth with white spots down the back and orange tufts
Image by Jon Brinn via Flickr

Sycamore moth (Acronicta aceris): Up to 40mm long with thick hair that is either yellow, brown or orange . They have bold white spots down their back, outlined in black, as well as tufts of dark orange or bright red hair on their back. Foodplants are most commonly Sycamore, Field Maple and Horse-chestnut.

 

A fluffy black caterpillar with a single brown line down the back
Image by Odd Wellies via Flickr

White Ermine moth (Spilosoma lubricipeda): Approximately 40mm long with a red, orange or pale dorsal line. Caterpillars at later development stages are covered in spines that can be reddish brown, dark brown or even black.

 

Brown caterpillars
A black moth with a purplish tint and a large head. it is hairless
Image by Aah-Yeah via Flickr

Elephant Hawk-moth (Deilephila elpenor): Thick bodies that grow up to 8cm in length, usually dark brown but bright green forms also occur. The name derives from their smaller, trunk-like head that extends from its more bulbous neck. They feature a spiked tail and four eyespots, although the second pair can be less visible on darker individuals. Most frequently found on Rosebay Willowherb, Great Willowherb, other willowherbs and bedstraws. 

 

A striped brown caterpillar
Image by David Short via Flickr

Square-spot Rustic moth (Xestia xanthographa): Greenish ochre in colour, with pale lines on its back and edged with dark, long, slanted markings on its sides in a row. Mainly feeds on grasses, plantains and Cleavers.

 

A pale brown caterpillar with darker brown stripes and dark brown spots
Image by Bjorn S via Flickr

Large Yellow Underwing moth (Noctua pronuba): Grows to a length of 45–50mm. Its body can be various shades of brown and green, with three lines down its back and dark patches on the inner side of the outer two lines – similar to the Square-spot Rustic. They also have darker sides with a lighter stripe above the legs. Feeds on a wide range of herbaceous plants and grasses including docks, brassicas, marigolds and Foxglove.

 

A hairless brown moth with speckles of cream and pink, and a cream stripe down its back
Image by Janet Graham via Flickr

Dot Moth (Melanchra persicariae): These caterpillars can reach up to 45mm in length and can be different shades of brown and green. They have three pale, distinctive lines on the dark prothoracic plate behind their head, as well as dark and light chevrons along a pale dorsal line down their backs. Feeds on a wide range of herbaceous and woody plants including Common Nettle, White Clover, Ivy, Hazel, Elder and willows.

Many of these caterpillars can also have a green form.   

Black and yellow/orange patterned caterpillars
Two black and lime green spotted caterpillars, with light coloured sparse hairs over the body
Image by Katja Schulz via Flickr

Large White butterfly (Pieris brassicae): Pale green-yellow in colour with black spots along its body. Visibly hairy. Also known as a Cabbage White due to its preference for cabbages as a food plant. 

 

A black moth with yellow and orange stripes with fine, long white hairs
Image by Dean Morley via Flickr

Buff-tip moth (Phalera bucephala): Distinctive caterpillar with a trellised black and yellow patterning and covering of pale hairs. The face is black and has an inverted yellow V. When fully grown this caterpillar measures up to 75mm in length. Most frequently found on sallows, birches, oaks and Hazel. 

 

A yellow-green caterpillar with black spots and stripes and short white hairs
Image by Peter O’Connor via Flickr

Six-spot Burnet moth (Zygaena filipendulae): Caterpillars feature a series of yellow and black dots on a green or greenish-yellow body. Feeds on Common Bird’s-foot-trefoil or occasionally Greater Bird’s-foot-trefoil. 

 

Dark brown/black caterpillars on a leaf. They have two cream stripes running the length of their back and have multiple protruding hairs
Image by Gilles San Martin via Flickr

Small Tortoiseshell butterfly (Aglais urticae): Caterpillars are initially black but show increasing variation in colour, with many developing pale yellow lines down their back and sides (some, however, may remain pure black). They have small clusters of short yellow spines and are fully grown at 30mm. Usually found on Common Nettle leaves.

 

A pale green caterpillar is on a plant. It has yellow and black spots in a repeating pattern
Image by Amanda Slater via Flickr

Mullein moth (Curcullia verbasci): One of the most striking and distinctive caterpillars to be found in Britain, they have a mixture of repeating black and yellow markings on a pale bluish-grey body. When fully grown they measure almost 50mm in length. Foodplants include mulleins, Common Figwort, Water Figwort and buddleias.

 

A green caterpillar with a black head. it has brown and green stripes down the length of its body and black spots
Image by hedera.baltica via Flickr

Box Tree moth (Cydalima perspectalis): Box Tree moths were introduced accidentally from south-east Asia and are a pest of Box trees. Caterpillars have green and black stripes running the length of the body, and the head is shiny black. Each of the body segments has white hairs and eyelike markings. 

 

 Black and spiky caterpillars
A black, spiked caterpillar with small white spots
Image by Bernard Dupont via Flickr

Peacock butterfly (Aglais io): Unlike the brightly coloured adult Peacock butterfly, the Peacock caterpillar has a velvety black body with small white spots and short spines on each segment. Most commonly feeds on Common Nettle and Hops.

 

A caterpillar with spikes and small white hairs. It has a black upper and orange lower with cream stripes
Image by Dean Morley via Flickr

Painted Lady butterfly (Vanessa cardui): Often found on thistles, Painted Lady caterpillars live for 5-10 days in a loosely woven silk nest inside which they feed continuously. They have dark bodies with pale narrow yellow-cream stripes. Particularly on younger larvae, spines can be alternating light and dark.

 

A group of black spiky caterpillars spinning a web on a green stalk
Image by Gilles San Martin via Flickr

Marsh Fritillary butterfly (Euphydryas aurinia): Caterpillars are black and hairy and initially live in groups on a larval web which is woven on the bottom-most leaves of Devil’s Bit Scabious plants. Prior to pupation, at the end of April, caterpillars will finally disperse to live independently. 

 

A brown caterpillar with white speckles and rings of black spikes
Image by Tim Worfolk via Flickr

Red Admiral butterfly (Vanessa atalanta): Caterpillars are black and spiny with a yellow stripe down each side and fine hairs along the body. They can be tricky to spot as they use silk to bind nettle leaves together to make a protective tent inside which they feed. 

 

Green caterpillars
A large green caterpillar on a tree trunk. it has small yellow spots and stripes on its back and two horns at one end
Image by Odd Wellies via Flickr

Lime Hawk-moth (Mimas tiliae): Caterpillars are distinctive having a large green body with pale yellow streaks on each segment and a bluish ‘horn’ at the tail end. Turns purple a short time before pupation. Foodplants include Limes, elms, Downy Birch, Silver Birch and Elder. 

 

A chunky green caterpillar. it has pink stripes on its legs and small green spikes on its body
Image by Patrick Clement via Flickr

Poplar Hawk-moth (Laothoe populi): A thick and chunky, bright green caterpillar with faint yellow lines running diagonally along the body. The tail end has a yellow ‘horn’ and some individuals have small, dark spots. Food plants include poplars, sallows and willows.

 

A chunky light green moth, it has a brown and yellow horn at one end and diagonal stripes along its back
Image by Jo Garbutt via Flickr

Privet Hawk-moth (Sphinx ligustri): Bright, lime-green caterpillar with white and purple stripes and a pale yellow spot on each segment. The tail end has a black curved hook. Usually found on Wild and Garden Privets, Ash, Lilac and Guelder-rose.

 

A round lime green caterpillar is walking along a plant stem. It is covered in very small white dots and subtle white stripes
Image by Julian Smith via Flickr

Eyed Hawk-moth (Smerinthus ocellata): Closely resembles the Poplar Hawk-moth caterpillar in that it is bright green with diagonal yellow lines. When mature it can be distinguished by its bluish tail horn. Foodplants include Apple, willows and sallows. 

 

a long, thin caterpillar with light green stripes running the length of its body
Image by Dean Morley via Flickr

Speckled Wood butterfly (Pararge aegeria): Bright green with faint dark green and yellow stripes running longitudinally along the length of the body. Feeds on False Brome, Cock’s-foot, Yorkshire-fog and Common Couch.

 

A green moth with a brown stripe down its back. It has a black hook at the end of its body and yellow patches along the side of its body
Image by Aah-Yeah via Flickr

Pine Hawk-moth (Sphinx pinastri): Dark green caterpillar with a brown stripe along the centre of its back and cream dashes that run either side of this. It has a brown head and a black tail horn. Feeds mainly on Scots Pine.

 

A lime green caterpillar with light black speckling and a yellow line running the length of the flank
Image by Ben Sale via Flickr

Bright-line Brown-eye moth (Lacanobia oleracea): Green caterpillar with a bright yellow line along its sides and tiny black spots. Found on a variety of herbacious and woody plants such as Common Nettle, Fat-hen, willowherbs, Hazel and Hop. Sometimes a pest of cultivated Tomatoes.

 

A slender green moth with rings of white spots. It has two white stripes running along its back leading toward a black hook at the base of the body
Image by Lies Van Rompaey via Flickr

Hummingbird Hawk-moth (Macroglossum stellatarum): Caterpillars are mainly green and have a thick, cream-yellow stripe running along the sides with a white line above. The tail horn is black with a yellow tip when mature. Feeds on Lady’s Bedstraw, Hedge Bedstraw and Wild Madder.

 

A green caterpillar with sparse dark hairs and two white stripes running the length of the back
Image by Mick Talbot via Flickr

Straw Dot moth (Rivula sericealis): Green caterpillar with two cream stripes running along the back creating a repeating hourglass pattern between them. Covered in long fine hairs. Not often seen, the caterpillars feed on a variety of grass species.

 

A plump green caterpillar with sparse hairs
Image by Artur Rydzewski via Flickr

Silver Y moth (Autographa gamma): Relatively easy to identify as it has only two sets of prolegs (small fleshy stubs beneath the body) and a rear clasper which means it walks with an arched body. It has a green body with a series of white wavy lines which may be broken by pale circles in later instars. Feeds on a range of low-lying herbacious plants including bedstraws, clovers, Common Nettle, Garden Pea and Cabbage. 

 

A plump green caterpillar with black speckles on its underside
Image by Harald Supfle.

Kentish Glory moth (Endromis versicolora): Large green caterpillar with diagonal pale stripes on each segment. Usually found on Silver Birch and less often on Downy Birch and Alder.

 

A chunky green caterpillar with orange spots. the spots are covered in spikes and small fine hairs
Image by Odd Wellies via Flickr

Emperor Moth (Saturnia pavonia): Green with black hoops containing yellow wartlike spots. Common in scrubby places whether they often feed on heathers, Meadowsweet, Bramble, Hawthorn and Blackthorn, amongst others. 

 

A vibrant green caterpillar with sparse white hairs
Image by gailhampshire via Flickr

Angle Shades moth (Phlogophora meticulosa): Usually green but can be mixed with shades of brown and/or yellow. A fine pale line runs down the back and a pale band runs down the sides of the body. Foodplants include a range of herbaceous and woody plants such as Common Nettle, Hop, Red Valerian, Bramble and Broad-leaved Dock. 

 

 Others
A plump palegreen caterpillar with black bands across its back and orange spots
Image by Frank Vassen via Flickr

Swallowtail butterfly (Papilio machaon): Striking bright green caterpillar with black bands and orange spots. British Swallowtail caterpillars feed solely on Milk-parsley. 

 

A black and orange striped moth on ragwort flowers
Image by Smudge 9000 via Flickr

Cinnabar moth (Tyria jacobaeae): Easy to identify having bold gold and black stripes. Most commonly feeds on the leaves and flowers of Common Ragwort where they can be found in their hundreds.

 

A brown caterpillar with thick spikes
Image by Darius Bauzys via Flickr

High Brown Fritillary butterfly (Argynnis adippe): Black caterpillar with a checkered pale pattern and yellow/buff spines. Covered in fine black bristles. Feeds on Common Dog-violet and Hairy Violet. 

 

A yellow caterpillar covered with black spots and patches. it has orange stripes running down the side of its body
Image by Conall via Flickr

Magpie moth (Abraxas grossulariata): Distinctive caterpillar with a creamy-white body, rows of black and white spots and an orange stripe that runs along the length of the body on the lower sides. Feeds on a range of deciduous trees such as Blackthorn, Hawthorn and Hazel as well as currant and gooseberry bushes. 

 

A short, rounded caterpillar (shaped like a woodlouse) with fine pink hairs. It is pink in colour with a green stripe running on either side of its body
Image by Gilles San Martin via Flickr

Small Copper butterfly (Lycaena phlaeas): Slug-shaped caterpillar covered in tiny white hairs. Exists in two forms: a purely green form and a green and pink striped form. Main foodplants are Common Sorrel and Sheep’s Sorrel. 

 

A black caterpillar with orange spots and stripes. the spots have spikes growing out of them that are also orange in colour
Image by Gilles San Martin via Flickr

Comma butterfly (Polygonia c-album): Mainly coloured brown and black with a large white mark towards the rear end of its back. Preferred foodplant is Common Nettle. 

 

A black caterpillar with an orange stripe running centrally along the back. On its sides are white patches with long white hairs growing out of them, the rest of the body has long black hairs
Image by gailhampshire via Flickr

Yellow-tail moth (Euproctis similis): Black caterpillar with a small hump behind its head. Two red/orange lines run along the back with a row of white markings wither side of them. They are covered in long black hairs and shorter white ones. Feeds on a wide selection of broadleaf trees and shrubs including Hawthorn, Blackthorn, oaks, roses, Hazel and willows.

 

A group of caterpillars. They are orange and blue striped with orange hairs protruding from the sides of its body
Image by gailhampshire via Flickr

Lackey moth (Malacosoma neustria): Large orange, blue and white striped caterpillars that are covered with fine orange hairs. Often feed in large groups on broadleaved trees and shrubs including Blackthorn, Hawthorn, cherries, Plum and Apple.

 

Recommended Reading:  
Field Guide to the Caterpillars of Great Britain and Ireland

This Bloomsbury Wildlife Guide allows identification of the common moth and butterfly caterpillars of the British Isles.

 

 

A Guide to the Caterpillars of the Butterflies of Britain and Ireland

A second edition fold-out guide to 57 of Britain’s butterfly species.

Toads in the Roads

It is in the earliest months of the year, when the weather turns milder and deeply saturating rains arrive, that adult toads, frogs and newts begin to emerge from their wintering hibernacula and make their long-standing annual journeys to the waterways in which they breed. It’s an ancient way of life for amphibians and a behaviour that pre-dates humankind by millennia.

Close up of a Toad crossing a loose, stony road at night.
Toad – Oli Haines

Roads are a relatively new addition to the landscape by comparison. A blink of an eye in toad evolution. They frequently bisect the paths that amphibians must navigate in order to reach their ancestral ponds. Being relatively slow-moving, small, and cryptically coloured, amphibians are incredibly vulnerable on tarmac roads. As such, it is estimated that two tons of toads are killed on roads each year in the UK.

This February was one of the warmest and wettest on record in England, and it felt every bit of it. Despite the gloom of early darkness and torrential rain, I was thrilled to sign up and join an enthusiastic local volunteer group of Toad patrollers, deep in the Devon laneways, to learn what work is being done to mitigate our impact on the amphibians currently making these critical journeys.

The Toads on Roads project was spearheaded by the amphibian charity Froglife over twenty years ago. Volunteers that are involved in the project put in considerable effort each year to monitor known and established toad crossings around the country. These are the places where toads gather in their largest numbers and are at significant risk of being run over in their attempts to reach spawning ponds.

The group I joined have, for a number of years, been protecting an intersection where three roads meet beside a large pond. As we gather in high-vis vests at around half five in the evening, it’s already fully dark. We’re wearing latex-free gloves and bearing large white buckets. The pond is swelling up either side of the road, flooding the tree roots in a muddy soup. The rain falls intermittently and, sure enough, a proud collection of male toads is already eagerly lining the roads awaiting the females.

Toads crossing for 800 metres sign on the side of a road with a grassy verge, wildflowers and long grass.
Toads crossing sign in Stalisfield Road by Pam Fray, via geograph.org.

We walk along the lane counting the toads we find and placing markers near them that are more visible for passing cars than the toads themselves are. It’s not such a busy road, but it is narrow and steeply enclosed between old earthen hedgerows that cars and tractors have clipped away over time, resulting in an overhang that the toads are incapable of climbing. Often, they become trapped along the lane. Where we find them in a predicament, we watch to observe the direction of their travel, and if the cars come, we gently lift the toads off the tarmac and place them in the verge where they appear to be headed.

A few drivers who come by slow down and ask what we’re doing. Many seem intrigued by the response, often vowing to take care as they go on. I’m told this is an improvement. As awareness of toad crossings and the work being done to monitor them increases, people are more understanding, though I’m assured there’s still animosity from some drivers who feel inconvenienced.

During some of the evenings on the patrol we encountered beastly weather; driving rain and flooded roads; and I marvelled at the dedication of the volunteers and their care for the amphibians crossing the roads. I learned that more people are approaching Froglife to get involved and that, due to increased awareness and publicity, the plight of toads is reaching more and more would-be patrollers. There have also been successful cases of temporary road closures to divert traffic during the heights of toad migration in the UK this year.

Close up of two toads, one on the back of another, crossing a gravelly road at night.
Toads – Oli Haines

It’s a complex web of challenges that contribute to amphibian population declines – not just nationally but globally. Land-use intensification threatens our waterways with myriad pollutants and our roads and construction projects fragment vital habitats or obliterate them entirely. It’s heartening that awareness is building. It has been such an inspiration to me to learn there’s a network of enthusiastic and caring volunteers out there in the winter nights, working at limiting the damage to amphibian populations, championing these remarkable and charismatic animals, and building hopeful connections in local communities while doing so.

If you feel call to get involved, visit the Froglife website where you can learn more about local toad crossings. There’s also abundant information on ways that you can make any local green spaces or gardens more amphibian friendly, such as making ponds, allowing wilder patches and encouraging greater invertebrate diversity.


Read our two-part Gardening for Wildlife blog for more information.