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Oak Eggar

Lasiocampa quercus

Not yet photographed by the community

Large brown moth; male flies fast by day seeking females.

Species Profile

Green List (widespread and common in suitable habitat)

Lifespan: 1 year (as adult moth); caterpillars take 10–11 months to develop
Size & Weight: Wingspan 32–40 mm; robust and hairy in appearance
Habitat: Heathland, moorland, woodland edges, and scrubland with abundant heather and bilberry
UK Distribution: Found throughout most of Britain and Ireland, though more common in upland and northern regions; resident species with single annual generation
Diet: Adult moths do not feed; caterpillars are herbivorous, feeding on heather (Calluna vulgaris), bilberry (Vaccinium myrtillus), and occasionally birch and hazel
Predators: Birds, spiders, and parasitoid wasps; badgers may dig up pupating caterpillars
Mating Season: May to July
Breeding: Females lay clusters of 50–100+ eggs on host plants; single brood per year; caterpillars overwinter and pupate in tough cocoons in soil or leaf litter in spring
Behaviour: Males are strongly attracted to females by pheromones and are often seen flying during daylight hours, particularly in warm afternoons. Females are more sedentary and cryptically coloured. The hairy caterpillars are gregarious when young but become solitary with age.

Did You Know?

•The caterpillars are covered in irritating hairs that can cause skin irritation in sensitive individuals
•Male Oak Eggars have distinctive bipectinate (feathery) antennae used to detect female pheromones from considerable distances
•Despite its name, the species does not exclusively feed on oak; heather is actually the primary food plant in the UK
•The cocoon is so tough that it was historically used by people as a natural purse or pouch
•Adults typically emerge in May and are active during warm, sunny afternoons when males can be seen patrolling heathland

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