Comma butterfly (Polygonia c-album)

Overview

🧬 Taxonomy & Classification

• Order: Lepidoptera
• Family: Nymphalidae (brush-footed butterflies)
• Subfamily: Nymphalinae
• Genus: Polygonia
• Species: Polygonia c-album
• Authority: (Linnaeus, 1758)
• Common Name: Comma butterfly
• Etymology: Named after the distinctive white comma-shaped marking (C) on the underside of the hindwing.

🪶 Morphological Description

🦋 Adult Butterfly

• Wingspan: 45–50 mm.
• Wing Shape: Deeply notched, ragged or scalloped wing edges—resembling a dead leaf.
• Coloration:
  • Upperwings: Bright orange with dark brown to black spots; forewings and hindwings scalloped.
  • Underwings: Cryptic, mottled brown, resembling dry leaves with a white comma (“c”) mark on the hindwing underside—a key identification feature.
• Sexual Dimorphism: Subtle; females slightly larger, but visual differences are minimal.

🐛 Caterpillar (Larva)

• Length: Up to 35 mm.
• Color: Variable; typically dark brown or black with white patches.
• Camouflage: Mimics bird droppings for protection from predators.
• Spines: Prominent branched spines cover the body.

🥚 Egg

• Shape: Ribbed and dome-shaped.
• Color: Pale green initially, turning dark before hatching.
• Laid Singly: On the upper side of host plant leaves.

🐚 Chrysalis (Pupa)

• Color: Typically brown or grey, with metallic gold spots.
• Shape: Angular and suspended by the cremaster from twigs or stems.

🌱 Habitat & Range

📍 Distribution

• Europe: Widespread across western, central, and southern Europe.
• Asia: Extends eastward through temperate Asia to Japan.
• Absent: From the far north (e.g., northern Scandinavia) and extreme Mediterranean dry zones.

🌿 Preferred Habitats

• Deciduous woodland edges and clearings.
• Hedgerows, riverbanks, gardens, parks, and orchards.
• Urban green spaces and countryside with nettles and hop plants.

🐛 Life Cycle & Phenology

🔁 Generations (Broods)

• Typically bivoltine (2 broods per year) in temperate areas:
  • Spring Brood: Emerges March–May.
  • Summer Brood: Emerges July–August.

In warmer areas, a third brood may occur.

⏳ Development Timeline

1. Egg Stage: 7–14 days.
2. Larval Stage: ~3 weeks.
3. Pupal Stage: ~2 weeks.
4. Adult Stage:
   • Summer adults live 2–4 weeks.
   • Autumn adults hibernate and can live for 6–7 months.

❄️ Overwintering Strategy

• Overwinters as an adult butterfly, hiding in hollow trees, sheds, leaf litter, or outbuildings.
• Enters diapause in autumn, reactivates in spring.

🧭 Behavior & Ecology

🧠 Camouflage & Mimicry

• The ragged wings and cryptic underside coloration closely mimic dead leaves—a prime example of protective mimicry.
• Active camouflage both during hibernation and rest.

🛫 Flight Pattern

• Energetic, erratic flight interspersed with basking.
• Frequently perches on tree trunks, brambles, or paths.

🧬 Polymorphism

• Two seasonal forms (a type of seasonal dimorphism):
  • Summer Form (hutchinsoni): Brighter, orange-tinted, does not hibernate.
  • Autumn Form: Darker, optimized for hibernation with more effective leaf-like underwing camouflage.

🍽️ Feeding Behavior

• Adults:
  • Nectar (thistles, bramble, ivy, buddleia).
  • Tree sap, fermenting fruit, aphid honeydew.
• Caterpillars:
  • Prefer nettles (Urtica dioica), hop (Humulus lupulus), elm (Ulmus spp.), currant (Ribes), and willow (Salix).

🌍 Ecological Role

• Pollinator: Minor role due to preference for tree sap and fruit, but does aid in pollination of late-summer flowers.
• Prey: Food source for birds, spiders, and predatory insects.
• Bioindicator: Presence and population trends reflect the health of woodland edge ecosystems.

🔬 Evolution & Adaptations

• Adaptation to climate: Expanded its range and increased brood frequency due to climate warming.
• Leaf mimicry: Likely evolved to enhance survival during the hibernation period.
• Plasticity: Ability to produce different morphs depending on photoperiod and temperature.

📊 Conservation Status

• IUCN: Not evaluated globally, but regionally secure.
• UK: Population has increased significantly since the 1970s.
  • Benefited from increased cultivation of nettles and a warming climate.
• Threats: Habitat loss, pesticide use, and climate extremes may impact local populations.

🔎 Similar Species (Comparison)

📚 Further Reading & References

Butterfly Conservation [UK]: https://butterfly-conservation.org/

Thomas, J.A., et al. (2010). Butterflies of Britain and Ireland.

Asher, J., et al. (2001). The Millennium Atlas of Butterflies in Britain and Ireland.

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