# Brimstone moth (Opisthograptis luteolata) > A common yellow geometrid moth of Europe and adjoining regions; harmless to people and often seen resting by day on shrubs and buildings. Source: https://insectscanner.com/species/brimstone-moth/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Brimstone moths do not bite or sting and are not poisonous. They are harmless to people; handle gently if needed as moth scales rub off easily. **Pets:** Not toxic to pets. Large numbers of caterpillars could, in theory, cause minor stomach upset if eaten by a pet, but this is unlikely in normal situations. ## Quick facts - Scientific name: Opisthograptis luteolata - Also called: Yellow brimstone moth - Order: Lepidoptera (Moths and butterflies) - Family: Geometridae (Geometer moths) - Size: 30-45 mm wingspan - Colours: Bright yellow, Golden yellow, Brown-orange, Pale green (larva) - Habitat: Woodland edges, hedgerows, gardens, parks and scrub; common in suburban and rural areas. - Range: Widespread across Europe, parts of North Africa and western Asia; common in the British Isles and continental Europe. - Active: Adults from April to October in several overlapping broods; mostly nocturnal but often seen resting or disturbed by day. - Lifespan: Adult stage lasts about 1-3 weeks; complete development from egg to adult depends on temperature and may take several months including overwintering pupa. - Effect on plants: Minor defoliator - Pest: no ## Overview The brimstone moth is a small to medium-sized geometrid moth well known for its bright yellow colouring and chestnut-brown blotches along the leading edge of the forewings. Adults are seen from spring to autumn, flying by night and frequently resting by day on walls, hedges and tree trunks. The caterpillars feed on a wide range of broadleaf trees and shrubs. This species is widespread across Europe into North Africa and parts of western Asia. ## How to identify it Adult brimstone moths have a wingspan typically 30-45 mm. Forewings and hindwings are bright sulphur-yellow, with several chestnut-brown blotches along the leading edge of the forewing and a small white crescent-shaped mark outlined in brown near its centre; the intensity of markings varies by individual. When at rest the wings are held flat, showing the full yellow surface. The caterpillar is a brown to greenish-brown 'looper' that closely resembles a twig, with a double-pointed hump in the middle of the body and small projections along the sides. Pupae are formed in a loose cocoon among leaf litter or plant debris. - Bright yellow wings with chestnut-brown blotches along the leading edge of the forewing and a small brown-edged white crescent mark. - Wingspan 30-45 mm; wings held flat at rest showing full yellow surface. - Brown, twig-like looper caterpillars with a double-pointed hump in the middle of the body. ## Lookalikes - **Brimstone butterfly** (Gonepteryx rhamni): The brimstone butterfly is much larger with leaf-shaped wings (lemon-yellow in males, pale greenish-white in females) and a small orange spot on each wing, and rests with wings closed; the brimstone moth holds its wings flat and has brown blotches on the forewing edge. - **Yellow shell** (Camptogramma bilineata): Yellow shell is smaller and has a distinct pattern of thin darker wavy lines across the wings rather than the brown blotches along the forewing edge of the brimstone. ## Life cycle - **Egg:** Eggs are laid on leaves or twigs of host plants and hatch within a couple of weeks. - **Larva (caterpillar):** Twig-like brown or greenish caterpillars feed on host leaves for several weeks; unusually, the species can overwinter as a part-grown larva. - **Pupa:** Pupation takes place in a loose cocoon among leaf litter or plant debris; some individuals overwinter as pupae. - **Adult (moth):** Adult moths emerge to mate and lay eggs; they are active at night but often rest visibly by day. ## Diet and predators - Young eat: Leaves of trees and shrubs in the rose family (hawthorn, blackthorn, apple, plum, rowan and others). - Adults eat: Adults feed little; if they feed they take nectar from flowers or absorb moisture and nutrients from nectar or other sources. - Predators of the young: Birds, small predatory insects and parasitoid wasps are main enemies of caterpillars. - Predators of adults: Bats, nocturnal insectivorous birds and spiders take adult moths; daytime resting individuals may be taken by birds. ## Effect on plants and gardens Larvae feed on leaves of trees and shrubs in the rose family, especially hawthorn, blackthorn (Prunus spinosa), apple, plum and rowan. Feeding usually causes only light defoliation and rarely harms established trees. ## Where and when to find it Adults: on walls, hedges, tree trunks, garden shrubs and near lights. Larvae: on the twigs and leaves of host trees and shrubs (hawthorn, blackthorn, apple, plum, rowan). Pupae: in leaf litter or among vegetation. - Best time: Best seen April to October; adults at night near lights and by day resting on vegetation or building walls. - Tips: Look for bright yellow moths resting with wings flat on sunny walls or hedges in spring. Photograph from above to capture wing pattern; approach slowly to avoid startling a resting moth. ## Fun facts - Despite the name, the brimstone moth is a moth, not related to the brimstone butterfly. - Individuals show considerable variation in how strong their brown-orange markings are — some look almost pure yellow while others are heavily marked. - They are often one of the first brightly coloured moths seen in spring. ## Frequently asked questions ### Do brimstone moths bite or sting? No. They are harmless to people and do not bite or sting. ### Why is a brimstone moth in my house? Adults are attracted to light and may wander indoors at night or rest on walls and windowsills; they do not infest homes. ### Will brimstone moth caterpillars damage my trees? They feed on leaves but usually only cause light to moderate defoliation; healthy mature trees are rarely harmed. ### How can I get rid of brimstone moths in my garden? Control is usually unnecessary. If needed, hand-pick caterpillars, encourage predators (birds, parasitic wasps), or use targeted biological controls; avoid broad-spectrum insecticides. ### When can I see brimstone moths? Mainly from April to October, in several overlapping broods; they are mostly nocturnal but often visible resting by day. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/59588), [Wikipedia](https://en.wikipedia.org/wiki/Brimstone_moth). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.