Journal of Threatened Taxa | www.threatenedtaxa.org | 26 March 2024 | 16(3): 25010–25012

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)

https://doi.org/10.11609/jott.8675.16.3.25010-25012

#8675 | Received 08 August 2023 | Final received 04 January 2024 | Finally accepted 30 January 2024

A record of the Hoary Palmer Unkana ambasa (Moore, [1858]) (Insecta: Lepidoptera: Hesperiidae) from Assam, India

Sanath Chandra Bohra ¹, Manmath Bharali ², Puja Kalita ³ & Rita Roy ⁴

¹ Help Earth, 16, Raghunath Choudhury Path, Lachitnagar, Guwahati, Assam 781007, India.

¹ Wildlife Sciences, Department of Zoology, Gauhati University, Guwahati, Assam 781014, India.

² Department of Zoology, Pandu College, Guwahati, Assam 781012, India.

³ Parlly lane, Palasbari, Gauhati, Assam 781128, India.

⁴ Bamunimaidam BG Colony, Pub Bhaskar Nagar, Guwahati, Assam 781021, India.

⁴ Department of Zoology, Pub Kamrup College, Baihata Chariali, Assam 781381, India.

¹ sreptilian6@gmail.com (corresponding author), ² manmathbharali9@gmail.com, ³ pujakalita517@gmail.com, ⁴ rita276roy@gmail.com

Editor: Sanjay Sondhi, Titli Trust, Dehradun, India. Date of publication: 26 March 2024 (online & print)

Citation: Bohra, S.C., M. Bharali, P. Kalita & R. Roy (2024). A record of the Hoary Palmer Unkana ambasa (Moore, [1858]) (Insecta: Lepidoptera: Hesperiidae) from Assam, India. Journal of Threatened Taxa 16(3): 25010–25012. https://doi.org/10.11609/jott.8675.16.3.25010-25012

Copyright: © Bohra et al. 2024. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

Funding: None.

Competing interests: The authors declare no competing interests.

Acknowledgements: We would like to acknowledge Monish Kumar Thapa and Dr. Jayaditya Purkayastha for providing valuable comments on our manuscript.

Among the known members of the genus Unkana Distant, 1886, Unkana ambasa (Moore, [1858]) or the Hoary Palmer is a relatively large skipper belonging to the family Hesperiidae that was described from Java, southeastern Asia (Moore 1857). The Hoary Palmer has a fairly wide distribution throughout the tropical forests of southern and southeastern Asia, including northeastern India, Bangladesh, Sundaland, Myanmar, Thailand, Philippines, Vietnam, Malaysia, Singapore, Borneo, Java, and Indonesia (Evans 1932; de Jong & Treadaway 1993; Eliot 2006; van Gasse 2013; Varshney & Smetacek 2015). Nonetheless, this species requires a brief taxonomic revision and has been considered as an overlooked taxa for decades as several morphologically similar subspecies, namely, ambasa (Moore, [1858]) (type locality: Java), batara Distant, 1886 (type locality: Malaysia), mindanaensis Fruhstorfer, 1911 (type locality: Mindanao), attina Hewitson, 1886 (type locality: India), and tranga Evans, 1949 (type locality: Nias, Indonesia) were described by earlier researchers (Evans 1949), often creating difficulties in assigning sub-populations of different regions to their respective sub-specific names (de Jong & Treadaway 1993; Kunte et al. 2023). Moreover, lack of sampling and the absence of molecular phylogenetic data from their respective type localities make the validity of these subspecies questionable. In India, this species occurs ‘very rarely’ as it has been recorded only from a handful of localities confined to regions in and around the eastern and northeastern states, particularly Sikkim and West Bengal (Varshney & Smetacek 2015; Kunte et al. 2023). Surprisingly, in recent years, the maximum numbers of sightings have been reported from Buxa Tiger Reserve situated in Alipurduar district of West Bengal (Kunte et al. 2023).

Currently, Assam has only a single recent record of U. ambasa based on an egg laid on the top of a leaf that was photographed by Paresh Churi on 15 April 2019 in Rani (Kunte et al. 2023) which necessarily needs further confirmation following methods like rearing. However, prior to this observation, no record of this species existed from Assam, allowing us to confirm the occurrence of an adult U. ambasa for the first time from the state based on photographic evidence from the Nilachal hills, Guwahati (26.1675⁰N, 91.7111⁰E) situated on the southern bank of River Brahmaputra in the Kamrup Metropolitan district. On 11 March 2023, at 1316 h, we encountered an individual of U. ambasa which was identified following Evans (1949), clearly saying “Unh (Underside of the hindwing) mostly whitish with dark veins, Uph (Upperside of the hindwing) with a dark brown border reaching dorsum, Upf (Upperside of the forewing) dark brown with well separated hyaline white or pale yellow discal and apical spots”. Furthermore, the individual is a female since it matches with the description provided in Evans (1932) which states, “Unh in males dark brown with obscure purple wash, veins black, whitish central area extending to base 7, obscurely paler between veins near termen; females with a broad transverse white area crossed by black veins from base to below apex”. The butterfly was observed perching somewhat perpendicular to partially visible sunlight for approximately 15 minutes on the leaf of a low-lying bush, probably a Boehmeria sp. occurring roughly 1.2 m above the ground, before hovering and flying away towards the bamboo thickets. The Nilachal Hill has a small area of approximately 2.6 km² representing an overall habitat of significant disturbance due to human settlements with a few undisturbed dense patches in between, comprising of mixed moist deciduous-semi evergreen forests in association with a narrow hill stream surrounded by rocky cliffs, loose soils and small temporary pools (max. height 243 m).

Based on the above observation, the occurrence of U. ambasa from Assam is confirmed, leading to a range extension of the species by approximately 222 km south-eastwards from its nearest previously known locality, i.e., Buxa Tiger Reserve, West Bengal, making it another significantly important state record from northeastern India. Again, another specimen photographed on 18 December 2016 from Nilam Bazaar (uploaded by Vijay Anand Ismavel on https://indiabiodiversity.org/group/birdwatch/observation/show/1809834?lang=en) situated in the Karimganj District was presumed to be U. ambasa as mentioned in the Indian Biodiversity Portal requires a taxonomic reconfirmation since the photograph does not match with the descriptions provided in Evans (1932, 1949), thereby representing a case of misidentification (Tarun Karmakar & Monish Kumar Thapa in litt. July 2023).

We suggest further field investigations from other states of northeastern India as well to accurately determine the distributional pattern as well as conservational status of this lesser-known species.

For images - - click here for full PDF

References

de Jong, R. & C.G. Treadaway (1993). The Hesperiidae (Lepidoptera) of the Philippines. Zoologische Verhandelingen 288(1): 1–125.

Eliot, J.N. (2006). Updating The Butterflies of the Malay Peninsula. Malayan Nature Journal 59(1): 1–49.

Evans, W.H. (1949). A Catalogue of the Hesperiidae from Europe, Asia and Australia in the British Museum (Natural History). Trustees of the British Museum, London, 502 pp.

Evans, W.H. (1932). The Identification of Indian Butterflies, Bombay Natural History Society, Bombay. 2^nd edition. Reprinted by Today and Tomorrow’s Printers and Publishers, New Delhi, 454 pp.

Kunte, K., S. Sondhi & P. Roy (2023). Butterflies of India, v. 4.12. Published by the Indian Foundation for Butterflies. Accessed at https://www.ifoundbutterflies.org/unkana-ambasa, on 06 August 2023.

Moore, F. (1857). A Catalogue of the Lepidopterous Insects in the Museum of the Hon. East India Company. W.H. Allen and Co., London, 278 pp.

van Gasse, P. (2013). Butterflies of India – Annotated Checklist. Kruibeke, Belgium, 161 pp.

Varshney, R.K. & P. Smetacek (eds.). (2015). A Synoptic Catalogue of the Butterflies of India. Butterfly Research Centre, Bhimtal & Indinov Publishing, New Delhi, ii + 261 pp + 8 pls.