- Lifespan
- 2–3 weeks as an adult butterfly; caterpillar stage lasts several weeks depending on generation
- Size & Weight
- Wingspan 32–36 mm
- Habitat
- Chalk and limestone grasslands with abundant horseshoe vetch, typically on warm south-facing slopes with sparse vegetation.
- UK Distribution
- Restricted to southern England, primarily Sussex, Kent, Surrey, and Hampshire; resident species with multiple generations per year, absent in winter as pupae.
- Diet
- Adults feed on nectar from bird's-foot trefoil, horseshoe vetch, and other wildflowers; caterpillars feed exclusively on horseshoe vetch (Hippocrepis comosa).
- Predators
- Spiders, robber flies, parasitic wasps, and insectivorous birds; caterpillars vulnerable to parasitoid wasps.
- Mating Season
- May to September with two or three broods per year
- Breeding
- Females lay single eggs on horseshoe vetch plants; caterpillar stage 3–4 weeks, pupation occurs either within weeks (producing summer brood) or overwinters as pupae; two to three generations annually.
- Behaviour
- Males are highly territorial, perching on low vegetation and pursuing rivals and females in rapid, erratic flight. They are strongly attracted to hilltops and warm, sunny conditions. Females are more cryptic and spend time laying eggs on host plants.