British caterpillars: how to identify 10 common species

You might be able to identify some of the most common British butterflies and moths, but what about their caterpillars?

Take a look at our tips for identifying 10 of our most common British caterpillars, find out what they eat and when and where to spot them.

Comma butterfly (Polygonia c-album)

Like the adult comma butterfly, which resembles a tattered leaf with its scalloped edges and rust-coloured hue, the comma caterpillar is a master of disguise. Its orange-brown markings and bright white 'saddle' mark make it look like a bird dropping, so it can crawl under the radar of predators when feeding on stinging nettles.

Large white butterfly (Pieris brassicae)

The large white caterpillar is pale green-yellow with striking black spots and visible hairs on its body. Its bold appearance is a warning to predators to eat it if they dare! The caterpillar accumulates mustard oil from its foodplant, which makes it taste unpleasant.

The foodplant in question is cabbage, which can make it unpopular with allotment owners and has earned the large white butterfly its alternative name, cabbage white.

Cinnabar moth (Tyria jacobaeae)

The cinnabar moth caterpillar is hard to miss. It looks as though it’s wearing a rugby shirt due to its distinctive black and orange stripes, but these bright colours have a very practical use. They warn predators that the caterpillar tastes foul. It acquires this taste by storing toxins from its foodplant, ragwort.

If that wasn't enough, cinnabar caterpillars have even been known to display cannibalistic behaviour if food is scarce!

Peacock butterfly (Aglais io)

In contrast with the brightly-coloured adult peacock butterfly, its caterpillar is a velvety jet-black peppered with small white spots. It has short spines, which help to protect it from predators.

Peacock caterpillars also ward off predators by coming together and jerking their bodies in unison, giving the illusion they are a much bigger animal. They will also curl up into a ball and drop to the floor or regurgitate a green substance to keep predators away.

Sycamore moth (Acronicta aceris)

The sycamore moth caterpillar is one of the hairiest and brightest caterpillars in the UK, with a full covering of yellow and orange hairs and a strip of black-edged white spots along the centre of its back. It's a world away from its grey adult form.

The sycamore moth is mostly found in the South East of England, but recent records show it may be spreading northwards and westwards into Wales.

Speckled wood butterfly (Pararge aegeria)

The speckled wood is the only British butterfly that can overwinter in two stages – either as a caterpillar or as a pupa. As a result, the adult butterflies can be seen as early as March and as late as October, especially in the south.

Speckled wood caterpillars are bright green with faint dark green and yellow stripes.

Puss moth (Cerura vinula)

With a bright green body, a pink face, a dark patch on its back and two whip-like tail appendages, there's no mistaking the puss moth caterpillar.

If it feels threatened, it will rear up and wave around its tail-whips. If the predator still isn't getting the message, it can even squirt formic acid from its thorax.

Elephant hawk-moth (Deilephila elpenor)

Named because of its likeness to an elephant's trunk, the chunky elephant hawk-moth caterpillar is usually brown, though a bright green form also occurs. It has large eye spots, a spiky tail and scale-like markings. When threatened, it can swell up, making itself appear bigger – an intimidating scare tactic when combined with its large eye spots!

Small tortoiseshell butterfly (Aglais urticae)

Small tortoiseshell caterpillars are black and yellow and covered in bristles. They lead fascinating lives, building a communal web at the top of their nettle plant when they hatch. As they grow and consume the nettle leaves, they move onto new nettles, building new webs along the way. Soon, a whole trail of webs filled with shed caterpillar skins and droppings leads right back to the plant where they were laid.

Emperor moth (Saturnia pavonia)

An impressive and unmistakable caterpillar. It is bright green, hairy, and has yellow wart-like spots ringed in black.

Emperor moths are the only UK members of the Saturniidae family – the group of moths that includes the silk moths of the tropics.