Butterflies come in a stunning array of colors and patterns. While many butterflies have bright, eye-catching hues, some species sport more subdued shades. One type of butterfly known for its dark green coloring is the Green Hairstreak.
With over 20,000 species worldwide, butterflies display incredible diversity in their appearances and behaviors. From the large and vibrant Blue Morpho to the tiny and cryptic Gray Ministreak, butterflies inhabit every continent except Antarctica. Though many butterflies boast flamboyant wings, there are also species that exhibit more muted tones of brown, gray, and green.
Dark green is an uncommon color in the butterfly world. Most green-hued butterflies have a lighter, more yellowish tone. True dark green butterflies are quite rare. So which butterfly species sport deep emerald wings?
The Green Hairstreak
The standout dark green butterfly is the Green Hairstreak (Callophrys rubi). Found throughout Europe, Asia, and North America, the Green Hairstreak lives in a variety of habitats, including forests, hedgerows, grasslands, and moors.
The wings of the Green Hairstreak exhibit a brilliant green color on the upper surfaces. The undersides are a pale gray-green with a white-rimmed black spot on each wing. The butterfly has a wingspan of 1 to 1.6 inches (32 to 38 mm).
Male Green Hairstreaks display bright green upper wings. Females have larger and duller wings that are dark gray-brown. Both genders have the trademark white-ringed black spot underneath each wing.
The Green Hairstreak gets its common name from the thin white line that bisects its green upper wings—reminiscent of a hair parting. Its scientific name rubi refers to the brambles and wild raspberries that the butterfly frequents.
Life Cycle
The Green Hairstreak goes through a complete metamorphosis with four life stages: egg, larva, pupa, and adult. The cycle begins in early spring when females lay tiny green eggs on the buds or stems of host plants. Caterpillars emerge within two weeks.
The larvae feed on a variety of plants, including rockrose, mouse-ear, birdsfoot trefoil, and wild raspberries. They molt several times over 2-4 weeks as they grow. In the last molt, caterpillars reach about 0.8 inches (20 mm) long.
When fully grown, the caterpillars form pupae which are attached to plants or debris. Inside the brown chrysalis, the larva transforms into the winged adult butterfly. After 10-15 days, the Green Hairstreak emerges from the pupa.
Adult Green Hairstreaks live for around three weeks during which time they focus on feeding, courting, mating, and laying eggs. The butterfly gets nectar from flowers like bugle and bramble. Males will patrol territories waiting for females to mate with.
There are two generations per year. The first emerges in spring and the second in late summer. The species overwinters as pupae.
Identification Tips
When trying to identify a dark green butterfly, there are some key characteristics of the Green Hairstreak to look for:
- Small size—up to 1.6 inches wingspan
- Brilliant green upper wings with thin white line
- Pale gray-green underwings with white-ringed black spots
- Males greener than females
- Found in open habitats like meadows and moors
- Active March-June and August-September
The Green Hairstreak is most likely to be confused with the Brown Hairstreak (Thecla betulae). However, the Brown Hairstreak is larger, has orange upper wings, and lacks the green sheen.
Threats and Conservation
Though widespread, the Green Hairstreak has experienced some population declines, particularly in the UK. However, its conservation status is currently of Least Concern.
Habitat loss poses the biggest threat to this butterfly. The clearing of scrub, forests, and hedgerows for agriculture and development destroys breeding areas and nectar sources. Pesticide use also reduces larval host plants.
Climate change may impact Green Hairstreaks through increased drought stressing larval plants and disrupting synchronicity between butterfly and plant life cycles. Invasive species are another concern as they degrade habitats.
Conservation priorities for the Green Hairstreak include protecting and restoring key breeding habitats, creating wildlife corridors, planting native wildflowers, limiting pesticide use, and monitoring populations. The UK has a designated Green Hairstreak butterfly reserve.
Other Dark Green Butterflies
While the Green Hairstreak is the archetypal dark green butterfly, some other species display deep green hues, at least in certain populations or forms. These include:
- Eastern Tailed Blue (Cupido comyntas) – Some females have dark green undersides
- Mottled Green Hairstreak (Parrhasius polibetes) – Has velvety green undersides
- Lime Butterfly (Papilio demoleus) – Tropical species with pale green wings
- Green-underside Blue (Euchloe ausonia) – Male’s green underside shows through upper wings
- Monarch (Danaus plexippus) – Rare dark green females found
However, these species do not display the consistently brilliant emerald hue of the Green Hairstreak.
Conclusion
With its vivid green coloration, the Green Hairstreak butterfly stands out among its less showy relatives. Though populations face some threats from habitat loss and climate change, this adaptable butterfly remains widely distributed. Protecting vulnerable breeding areas will help ensure the iconic Green Hairstreak continues to brighten meadows and moors with its jewel-toned wings.
