How to identify common British caterpillars

Here are 12 common British caterpillars for you to look for, with typical foodplants listed to help you identify them. Lengths quoted are maximum sizes of fully grown larvae.

Large white caterpillar

Illustrations by Felicity Rose Cole

Advertisement
1

Large white caterpillar Pieris brassicae (above) 

45mm. Clusters on cabbages, lettuces and nasturtiums. Bright spotted body warns of foul taste

Large white caterpillars are found in March and October but are most common in July and August. Adults are active between April and September.

Small tortoiseshell caterpillar
Small tortoiseshell caterpillar
2

Small tortoiseshell caterpillar Aglais urticae

30mm. Clusters in a silk web on nettles until nearly fully grown; crawls away separately to pupate.

Small tortoiseshell caterpillars can be seen from May to June, with adults potentially being active all year.

Comma caterpillar
Comma caterpillar
3

Comma caterpillar Polygonia c-album

35mm. On hops and stinging nettles; hatchlings resemble bird droppings, soon developing white ‘saddle’ mark.

Comma caterpillars are seen from late April to mid-September. Comma butterflies are active all year round.

Cinnabar moth caterpillar
Cinnabar moth caterpillar
4

Cinnabar moth caterpillar Tyria jacobaeae

28mm. On common ragwort, often shredding the plants. ‘Boom and bust’ population fluctuations locally. These black and yellow caterpillars are very distinctive and easy to identify as they look like they’re wearing a rugby shirt.

Cinnabar moth caterpillars can be found feeding from July to early September. Adults fly from May to early August.

Buff-tip moth caterpillar
Buff-tip moth caterpillar
5

Buff-tip moth caterpillar Phalera bucephala

70mm. On oak leaves. After hatching from egg cluster, larvae feed together, moving off alone when larger.

Buff-tip moth caterpillars are found between July and early October. Adults are active from late May to July.

Pale tussock moth caterpillar
Pale tussock moth caterpillar
6

Pale tussock moth caterpillar Calliteara pudibunda

45mm. On various broadleaved trees and shrubs, including birch and hops; colloquially known as ‘hop dog.’

Pale tussock moth caterpillars can be seen from late June to early October. Adults fly between July and August.

Why are caterpillars so varied?

Caterpillars can’t easily escape from predators because they’re slow-moving and haven’t grown wings yet. That means they either have to rely on camouflage so that predators don’t notice them (which gives us caterpillars that look like leaves, plant stems etc) or they’ve evolved to be bright and spikey so anything that might want to eat them knows that it would be a bad idea!

Photo © Russell Burden / Getty

Pair of tomato hornworm caterpillars feeding on tomato plant leaves
Sycamore moth caterpillar
Sycamore moth caterpillar
7

Sycamore moth caterpillar Acronicta aceris

40mm. On sycamore, cultivated and field maples, horse chestnut and London plane; an urban species.

Sycamore moth caterpillars are found from July to September. The adults are active from mid-June to early August.

Vapourer moth caterpillar
Vapourer moth caterpillar
8

Vapourer moth caterpillar Orgyia antiqua

40mm. On most native or cultivated trees or shrubs, including cherry laurel. Bizarre tufts; distasteful.

Vapourer moth caterpillars are found from May to early September. Adults fly from July to October in the south and September to October in the north.

Knot grass moth caterpillar
Knot grass moth caterpillar
9

Knot grass moth caterpillar Acronicta rumicis

40mm. On plants including sorrel, broadleaved dock, mint and bramble. Two generations in southern Britain.

Knot grass moth caterpillars can be found from June to October. The adults fly from May to June and from August to early September.

Grey dagger moth caterpillar
Grey dagger moth caterpillar
10

Grey dagger moth caterpillar Acronicta psi

40mm. On broadleaved trees and shrubs – hawthorn, apple and birch. Yellow stripe is camouflage on stems.

Grey dagger moth caterpillars can be found from July to early October. Adults are active from mid-May to August.

Dot moth caterpillar
Dot moth caterpillar
11

Dot moth caterpillar Melanchra persicariae

45mm. On a wide range of herbs and shrubs. Brown or green varieties, always with ‘go-faster’ chevrons.

Dot moth caterpillars are found from August to October. Adults fly from late June to August.

Lime hawkmoth caterpillar
Lime hawkmoth caterpillar
12

Lime hawkmoth caterpillar Mimas tiliae

70mm. Mainly on lime, particularly in urban areas; also birch and alder. Caterpillars are bright green to dark greyish-purple.

Advertisement

Lime hawkmoth caterpillars can be seen from late June to mid-September. Adults fly from May to early June.

You might think caterpillars only have to worry about birds and other predators, but what happens when your food explodes?