Field Guide
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Green Hairstreak
Callophrys rubi
Not yet photographed by the community
Only green butterfly in UK; caterpillar feeds on gorse and broom.
Species Profile
Green List (not threatened)
- Lifespan
- Approximately 2 weeks as adults in the wild
- Size & Weight
- Wingspan 25–27 mm; very small and delicate
- Habitat
- Open, sunny areas with low-growing vegetation including gorse, broom, bird's-foot trefoil, and other legumes, often on heathland, grassland, and woodland edges.
- UK Distribution
- Found throughout England, Wales, and southern Scotland, with populations extending northwards. Resident species with a single generation per year; adults emerge in spring.
- Diet
- Larvae feed exclusively on plants in the pea family (Fabaceae), particularly bird's-foot trefoil, gorse, and clover. Adults feed on nectar from various flowers.
- Predators
- Birds, spiders, and robber flies are the main natural predators of adults and larvae.
- Mating Season
- April to June
- Breeding
- Females lay single eggs on the underside of host plant leaves. Larvae pupate in leaf litter and overwinter as pupae; one generation per year.
- Behaviour
- Males are highly territorial and perch on low vegetation, darting out to intercept passing females. The butterfly has a rapid, erratic flight close to the ground. It is typically active in warm, sunny weather and rests with wings tightly closed, revealing only the cryptic green underside.
- •The Green Hairstreak is the only butterfly in the UK with a bright green underside, providing excellent camouflage among vegetation.
- •Males have a distinctive behaviour of 'puddling' at damp soil patches to obtain minerals and salts.
- •The species has a very short adult lifespan of only 10–14 days, making spring sightings relatively brief.
- •Despite its small size, the Green Hairstreak has expanded its range northwards in the UK over recent decades, possibly linked to climate change.
- •The caterpillar produces a secretion that attracts ants, which may provide some protection from parasites and predators.
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