Brown Hairstreak butterfly

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Brown Hairstreak butterfly

The brown hairstreak is a butterfly in the family Lycaenidae. The range includes most of the Palaearctic.

Scientific classification

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Lepidoptera
  • Family: Lycaenidae
  • Genus: Thecla
  • Species: T. betulae
  • Binomial nameT: hecla betula

About Brown Hairstreak

The largest of the UK hairstreak family, the brown hairstreak is an elusive butterfly, spending most of the time either high in the tops of ash “master” trees, where they feed on honeydew from aphids and bask in the sun, or amongst thick hedges.  Adults fly from late July, peaking in August, and can remain on the wing until November.  They are found on woodland edges and hedgerows in Southern England, laying their eggs on blackthorn.

Brown Hairstreak Habitat

This species lives in habitats where Blackthorn, the primary larval foodplant, is abundant, such as hedgerows and woodland.

As the primary larval plant is Blackthorn, the Brown Hairstreak can be found wherever this shrub is established and not flailed annually, such as hedges, scrub, and woodland.


The adult male Brown Hairstreak lacks the golden orange flashes on the upper-forwings which the female has.

The Brown Hairstreak is a single brooded species being on the wing from late July to early September with the males emerging first. The elusive adults occurs in low numbers over large areas. Males may congregate around a ‘master tree’ usually an Ash near the breeding colony.

The adults feed primarily on aphid honeydew which coats the leaves of Ash although adults can sometimes be seen feeding on flowers. The females may be found feeding on Fleabane, Hemp Agrimony and Brambles between periods of egg laying.

The Brown Hairstreak is a Priority Species for conservation due to the continued loss of habitat and resulting drop in population.

How to identify Brown Hairstreak

The brown hairstreak is the largest hairstreak found in the UK. The top side of the wings are brown but females have an orange mark in the top corner of each. The underwings are a distinctive bright orange with two white lines streaked across and small tails protruding from the lower wing.

Size and Family

  • Family: Hairstreaks
  • Size: Small/Medium
  • Wing Span Range (male to female): 38-40mm

Life cycle and food plants

In Europe the female lays her eggs on blackthorn (Prunus spinosa) in late August which overwinter, hatching the following spring when the buds are breaking. It has been found that the best way to find breeding sites for this species is to look for the conspicuous white eggs in the winter.

The larvae are extremely well camouflaged and feed only at night, remaining motionless during the day. Pupation takes place in leaf litter on the ground in late June or early July and are attractive to ants who will bury them in shallow cells.

Also More: Brimstone butterfly

Brown Hairstreak images

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