Taxonomy
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Insecta
- Order: Lepidoptera
- Family: Nymphalidae
- Subfamily: Charaxinae
- Genus: Polyura
- Species: Polyura athamas
- Authority: (Cramer, 1779)
- Synonyms: Charaxes athamas Cramer, 1779
Common name
Great Nawab (also referred to as the Indian Nawab in some regional field guides).
Description
Polyura athamas is a medium‑to‑large butterfly, with a wingspan typically ranging from 70 to 90 mm. The dorsal (upper) wing surfaces are predominantly dark brown to black, marked by a series of pale, sometimes iridescent, greenish‑blue or silver streaks that radiate from the wing base toward the outer margins. The hindwings possess a characteristic tail‑like extension, a distinctive trait of the genus Polyura. The ventral (under) side of the wings displays a complex pattern of pale bands and spots set against a brown background, providing camouflage when the butterfly rests with wings closed.
Distribution
Polyura athamas occurs throughout the Indian subcontinent and parts of Southeast Asia. Its range includes:
- India (north‑eastern states, the Western Ghats, and the Himalayas)
- Nepal and Bhutan
- Bangladesh and Sri Lanka
- Myanmar, Thailand, Laos, and Vietnam
- Peninsular Malaysia and southern China
The species is primarily a lowland to hill‑forest dweller, occurring from sea level up to approximately 1,500 m elevation.
Habitat
The butterfly inhabits evergreen and semi‑evergreen forests, as well as secondary growth and forest edges. It is frequently observed near streams and in forest clearings where host plants are present.
Life cycle and biology
- Egg: Laid singly on the leaves of host plants.
- Larva (caterpillar): The caterpillars are green to brown, bearing a series of dorsal rows of short spines. They feed on the foliage of certain woody plants. Specific host‑plant records for P. athamas include members of the families Fabaceae (e.g., Millettia spp.) and Rutaceae, although comprehensive documentation is limited.
- Pupa: Pupation occurs within a loose silk web attached to the host plant or in leaf litter. The chrysalis is greenish with metallic markings.
- Adult: Adults are strong, fast flyers, often seen basking with wings partially opened. They feed on tree sap, overripe fruits, and occasionally on nectar.
Behavior
Males are territorial and frequently patrol forest edges, while females are more sedentary, focusing on oviposition sites. The species exhibits typical “hilltopping” behavior, where individuals congregate on prominent landscape features for mating.
Conservation status
The International Union for Conservation of Nature (IUCN) has not evaluated Polyura athamas separately; it is not listed on the Red List. Across most of its range the species is considered locally common and does not presently face major threats beyond generalized habitat loss due to deforestation and land‑use change.
References
- Cramer, P. (1779). De Uitlandsche Kapellen. Amsterdam.
- Evans, W.H. (1932). The Identification of Indian Butterflies. Bombay Natural History Society.
- Savela, M. (2023). “Polyura Hübner, 1819.” Lepidoptera and Some Other Life Forms.
- Collins, N.M. & Morris, M.G. (1985). Threatened Swallowtail Butterflies of the World. IUCN.
Note: While the general biology and distribution of Polyura athamas are well documented in lepidopteran literature, specific details regarding larval host‑plant associations and precise population trends remain incompletely studied.