Butterflies of eastern Assam, India

doi: http://doi.org/10.11609/jott.3177.9.7.10396-10420 | ZooBank: urn:lsid:zoobank.org:pub:639FB0A4-5215-41CB-A912-4C78E825B356

Editor: James Young, Hong Kong Lepidopterists Society, Hong Kong. Date of publication: 26 July 2017 (online & print)

Manuscript details: Ms # 3177 | Received 30 November 2016 | Final received 09 June 2017 | Finally accepted 15 July 2017

Citation: Singh, A.P. (2017). Butterflies of eastern Assam, India. Journal of Threatened Taxa 9(7): 10396–10420; http://doi.org/10.11609/jott.3177.9.7.10396-10420

Copyright: © Singh 2017. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Funding: Indian Council of Forestry Research& Education (ICFRE).

Competing interests: The author declares no competing interests.

Author Details: Arun P. Singh is currently working as a scientist with the Forest Research Institute, Dehradun. His experience pertains to the conservation and ecology of butterflies and birds across the Himalaya, over the last two decades.

Acknowledgments: The author is thankful to the Director, Rain Forest Research Institute (RFRI), Jorhat, Assam, India for providing all the necessary facilities to carry out the above work. Thanks are due to Abhijit Medhi, Geo-informatics laboratory, RFRI for drawing the GIS map and Monsoon Jyoti Gogoi for help in identification of butterflies.

Abstract: The paper provides information on butterfies sampled during random surveys from November 2014 to September2016 from eight reserve forest areas and Dehing-Patkai Wildlife Sanctuary, covering three districts (Tinsukhia, Dibrugarh & Sibasagar) in the eastern part of upper Assam which form part of the Indo-Burma hotspot. The survey revealed 237 species which included 33 species a listed as protected under various schedules of the Indian Wildlife (Protection) Act 1972 and 58 species that have distribution restricted to the eastern Himalaya and northeastern India in India. An anotated list of 375 species of butterflies so far recorded from eastern Assam that includes a large number of very rare species (Indian Yellow-vein Lancer Pyroneura margherita; Grey-lined Lascar Pantoporia dindinga assamica; Assamese/Conjoined Lascar Pantoporia assamica; Bi-coloured Hedgeblue Udara selma cerima; Vinous Oakblue Arhopala athada aphade; Magnificent Oakblue Arhopala anarte; White Punch Dodona henrici; Pale Striped Dawnfly Capilia zennara; Andaman Yellowbanded Flat Celaenorrhinus andamanicus hanna; Sikkim Ace Halpe sikkima; Baby Swift Polytremis minuta; Maculate Lancer Salanoemia sala; Veined Palmer Hidari bhawani; Pallid Forester Lethe satyavati; Peal’s Palmfly Elymnias peali; Blue Baron Euthalia telchinia; Blue Nawab Polyura schreiber assamensis; Tytler’s Dull Oakblue Arhopala ace arata; Orchid Tit Hypolycaena othona othona; Purple Brown Tailless Oakblue Arhopala arvina ardea; Malayan Bushblue Arhopala ammon ariel and Broad-branded Brilliant Simiskina phalena harterti) along with their site and month of record, endemicity and relative abundance status in India, is provided.

Keywords: endemic, evergreen forests, Indo-Burma Hotspot, northeastern India, protected species, rare.

Introduction

The forests of eastern Assam in northeastern India are contiguous with forests in the northern part of Myanmar. These semi-evergreen and evergreen forests form part of the Indo-Burma global biodiversity hotspot (New & Collins 1991), at its northern limit and harbour a large number of species ‘rare’ and ‘endemic’ to this region. Forests once covered most part of Assam but today exist in small to large fragmented patches, loosely joined together in four districts of eastern Assam namely Tinsukhia, Dibrugarh, Sivasagar and part of Jorhat districts, along the state boundary with Arunachal Pradesh and Nagaland states (Fig. 1). Due to rapid urbanization and increasing population pressure in the region, however, these forests are today threatened due to habitat degradation.

At least half a dozen butterflies have been described from eastern Assam. As far back as in 1865, Hewitson described the Spotted Royal, Tajuria maculata (Hewitson, 1865) (Lycaenidae). This was followed by description of the White Dawnfly, Capila pieridoides (Moore, 1878) (Hesperiidae) then the Pallid Forester Lethe satyavati de Nicéville, 1881 (Nymphalidae) from Sibsagar, the Silver Spotted Lancer Plastingia naga (de Nicéville, [1884] (Hesperiidae), and the Blue Quaker Pithecops fulgens Doherty, 1889 (Lycaenidae) and Yellow-vein Lancer Pyroneura margherita (Doherty, 1889) (Hesperiidae) from Margherita area by Doherty. Later, Norman (1953 & 1956) recorded some ‘very rare’ (as per Evans 1932) species from Sibasagar District in upper Assam, i.e., Yellow-vein Lancer P. margherita, Veined Palmer Hidari bhawani de Nicéville, [1889], Broad-branded Brilliant Simiskina phalena harterti (Doherty, 1889), Bi-coloured Hedgeblue Udara selma cerima (Corbet, 1937), Wavy Maplet Chersonesia rahrioides Moore, [1899], Conjoined Lascar Pantoporia assamica (Moore, 1881), Brown Forest Bob Scobura woolletti (Riley, 1923), Baby Swift Polytremis minuta (Evans, 1926), Maculate Lancer Salanoemia sala (Hewitson, [1866]), Vinous Oakblue Arhopala athada aphade Nicéville, 1895, and Isma sp. Distant, 1886.

The butterfly diversity of these forests remained poorly documented until recently Karthikeyan & Venkatesh (2011) recorded a ‘very rare’ species generally found in Southeast Asia in Assam, the Snowy Angle Darpa pteria (Hewitson, 1868) between 24–29 April 2011 from Jeypore Reserve Forest, Assam. Gogoi (2013a) listed 292 species from a Jeypore-Dehing forest area in eastern Assam. This was followed by Singh et al. (2015) list of 211 species from Gibbon Wildlife Sanctuary (GWS) (a remnant semi evergreen forest patch of 21km2 existing in Jorhat District of upper Assam, adjoining Sivasagar District close to Nagaland border) and also a small pictorial booklet by Neog (2015) from the GWS covering 200 species recorded by him. Singh (2015) also reported separately a ‘very rare’ species, the Veined Palmer Hidari bhawani from Sotai in Jorhat District of Upper Assam. Besides these there are no other comprehensive records available on butterflies of eastern Assam. Most of the recent focus has remained around Namdapha Tiger Reserve, which lies 60km east of Tinsukhia District in Arunachal Pradesh State or around Kaziranga National Park and adjoining the Karbi Anglong Hills, lying west of Jorhat District (Gogoi 2013b, 2015).

Study Area

The study area included eight reserve forest areas and along the road stretch inside the Dehing-Patkai Wildlife Sanctuary, covering three districts (Tinsukhia, Dibrugarh & Sibasagar) all in the eastern part of upper Assam (Figs. 1,2; Table 1; Images 1–6) situated on the border with Arunachal Pradesh and Nagaland states, between 26.96805–27.53889 N & 95.29500–95.96333 E. These reserve forests and Wildlife Sanctuary form small to large tracts of semi-evergreen and evergreen forests comprising the dominant tree Dipterocarpus retusus Blume (Hollong) along with Messua ferrea L. (Indian Rose Chestnut), Terminalia myriocarpa Van Heurck & Mull. Arg. (Hollock), etc., intermixed with bamboo brakes comprising Dendrocalamus hamiltonii Gamble; Pseudostachyum polymorphum Munro & Rattan Canes (Calamus spp.) in ravines and river banks. Numerous fresh water perennial streams and rivers (Burhi-Dehing, Dilli, Tipong, Tirap, and Namsik rivers) transgress these forest tracts in eastern Assam covering the study area, while the main river Brahmaputra forms the northern boundary of these forest ranges (Table 1; Fig. 1).

Material & Methods

Random surveys for sampling butterflies were carried out from 18 November 2014 to 09 September 2016 (Table 1). Pollard walk methodology (Pollard 1982) was used for sampling butterflies. This was done by walking for one hour (approximately 1km) on each transect inside the forest on trails; 2–11 transects/trails were covered at each site. A total of 39 hours (approximately) of sampling was done covering 19 days spread over a five month period during most of the seasons of the year (February: mainly winter; March: spring; June: pre-monsoon/dry summer; 31 August–September: monsoon; November: winter). The altitudinal range covered varied from 85m (lowest) in Padumoni RF near the Bhramaputra River basin to as high as 471m (highest) in Tipong RF-Lekhapani RF tract, bordering Changlang District of Arunachal Pradesh.

The relative abundances of all the species sampled were pooled and ranked from lowest to the highest. All taxa were then divided into four equal classes or categories with an equal number of species. Based on the quartile divisions of their relative abundances, all these taxa were ranked as Uncommon (Q1) = 1 individual recorded (minimum abundance); Fairly Common (Q2) = 2–3; Common (Q3) = 4–9; and Very Common (Q4) = 10– 96 (maximum number of a species recorded); Median value = 3 (Table 2).

Identification of butterflies was carried out on the spot during sampling or from photographs taken in the field as the majority of the species was photographed (Images 7–43 [12-42 are endemic to northeastern India]). For identification the field guides and papers (Evans 1932; Wynter-Blyth 1957; Smith 2006; Kehimkar 2008; Singh 2011; Gogoi 2012, 2013a; Sondhi et al. 2013; Sondhi & Kunte 2014; Smetacek 2015) and web resources (http://www.ifoundbutterflies.org/; http://flutters.org/), were used. Nomenclature was followed using the website http://www.nfic.funet.fi/pub/sci/bio/life/ insecta/lepidoptera/ ditrysia/ papilionoidea/

Results and Discussion

A total of 237 species were recorded during the present survey. Thirty-three species amongst these (Table 2) have been listed as protected under various schedules of the Indian Wildlife (Protection) Act 1972 (Anonymous 1997) (2 under Schedule I, 29 under Schedule II, and 2 under Schedule IV) and are protected by law. Seventy-seven species recorded have distribution restricted to the eastern Himalaya and northeastern India (Table 2). Only Blue Quaker Pithecops fulgens, Yellow-vein Lancer Pyroneura margherita, Wavy Maplet Chersonesia rahroides and Tytler’s Dull Oakblue Arhopala ace arata Tytler, 1915 which were recorded a long time back by Doherty (1889) & Norman (1953 & 1956) from eastern Assam, were also recorded during the present survey.

As per Evans (1932), species that are noteworthy from the point of view of conservation amongst these (Table 2) are: (i) ‘Very rare’ and ‘endemic’ species: Yellow-vein Lancer Pyroneura margherita; (ii) ‘Rare’ and ‘endemic’ species: Yellow Fringed Swift Caltoris aurociliata (Elwes & Edwards, 1897), Wavy Maplet Chersonesia rahroides, Silver Royal Ancema blanka minturna (Fruhstorfer, 1912), Spotted Sailer Neptis magadha khasiana Moore, 1872, Pallid Forester Lethe satyavati; Pale Wanderer Pareronia avatar (Moore, [1858]), Royal Cerulean Jamides caeruleus (Druce, 1873), Blue Quaker Pithecops fulgens fugens, Grey Baron Euthalia anosia anosia (Moore, [1858]), Great Archduke Lexias cyanipardus cyanipardus (Butler, [1869]), Eastern Striped Albatross Appias olferna Swinhoe, 1890, Dot-dash Sergeant Athyma kanwa phorkys (Fruhstorfer, 1913), Wizard Rhinopalpa polynice birmana Fruhstorfer, 1898, Dark Velvet Bob Koruthaialos butleri butleri (deNicéville, [1884]), Plain Bushbrown Telinga malsarida Butler, 1868, Tailed Red Forester Lethe sinorix sinorix (Hewitson, 1863), Chinese Bushbrown Mycalesis gotama charaka Moore [1875], Branded Yamfly Yasoda tripunctata tripunctata (Hewitson, 1863), Great Zebra Graphium xenocles xenocles (Doubleday, 1842), Sylhet Oakblue Arhopala silhetensis silhetensis (Hewitson, 1862), Unbroken Sergeant Athyma pravara acutipennis Fruhstorfer, 1906, Great Blue Mime Papilio paradoxa telearchus (Hewitson, 1852), and Watson’s Bushbrown Mycalesis adamsoni Watson, 1897; (iii) ‘Not rare’ and ‘endemic’ species: Tufted Ace Sebastonyma dolopia Hewitson, 1868, Tiger Palmfly Elymnias nesaea Linnaeus, 1764, Plain Earl Tanaecia jahnu jahnu (Moore, [1858]), Extra Forest Bob Scobura cephala Hewitson, 1876, Yellow-veined Flat Mooreana trichoneura pralaya Moore, [1866], Perak Lascar Pantoporia paraka paraka (Butler, 1879), Plain Sailer Neptis cartica Moore, 1872, Black Forester Lethe vindhya vindhya (C. & R. Felder, 1859), Powdered Baron Euthalia monina kesava (Moore, 1859), Glistening Cerluean Jamides elpis pseudelpis (Butler, 1879), Dark Yellow-banded Flat Celaenorrhinus aurivittata aurivittata (Moore, 1878), Pallid Nawab Charaxes arja arja (C. & R. Felder, [1867]), Courtsean Euripus nyctelius nyctelius (Doubleday, 1845), Dingiest Sailer Neptis harita harita Moore, [1875], White Dargontail Lamproptera curius curius (Fabricius, 1787), Northern Spotted Ace Thoressa cerata Hewitson, 1876, Dusky Diadem Ethope himachala (Moore, 1857), Common Raven Papilio castor polias Westwood, 1842, Light Straw Ace Pithauria stramineipennis Wood-Mason & deNicéville, [1887], Jewelled Nawab Charaxes delphis delphis (Doubleday, 1843), Dusky Yellow-breast Flat Gerosis phisara phisara (Moore, 1884), Dark Catseye Zipaetis scylax scylax Hewitson, 1863, Common Tree Yellow Gandaca harina assamica Moore, [1906], and Dark Archduke Lexias dirtea khasiana (Swinhoe, 1890), as compared to the rest of the other species sampled.

Ninteen taxa found during this survey have not been previously recorded by Gogoi (2013a) from Jeypore-Dehing forest, eastern Assam, India. These are, Lime Swallowtail Papilio demoleus demoleus Linnaeus, 1758, Tailed Jay Graphium agamemnon agamemnon (Linnaeus, 1758), Common Windmill Byasa polyeuctes polyeuctes (Doubleday, 1842), Eastern Striped Albatross Appias olferna Swinhoe, 1890, Bright Sunbeam Curetis bulis bulis (Westwood, 1851), Burmese Sunbeam Curetis saronis Moore, 1877, Bhutia Line Blue Prosotas bhutea (deNicéville, [1884]), Forest Pierrot Taraka hamada mendesia Fruhstorfer, 1918, Royal Cerulean Jamides caeruleus, Glistening Cerluean Jamides elpis pseudelpis, Silver Royal Ancema blanka minturna (Fruhstorfer, 1912), Jewelled Nawab Charaxes delphis delphis, Angled Red Forester Lethe chandica flanona Fruhstorfer, 1911, White-Bar Bushbrown Mycalesis anaxias aemate Fruhstorfer, 1911, Dark Archduke Lexias dirtea khasiana, Yellow-veined Flat Mooreana trichoneura parlaya, Moore’s Ace Halpe porusporus (Mabille, [1877]), Orange Awlet Burara jaina vasundhara (Moore, [1866]), and Yellow-Fringed Swift Caltoris aurociliata (Elwes & Edwards, 1897).

Twenty-five taxa found during the present survey have not been recorded earlier by either Singh et al. (2015) or Neog (2015) from Gibbon Wildlife Sanctuary lying west of the study area in the adjoining Jorhat district of Upper Assam. These species are: Tailed Sulphur Dercas verhuelli doubledayi Moore, [1905], Bright Sunbeam Curetis bulis bulis, Burmese Sunbeam Curetis saronis saronis, Glistening Cerluean Jamides elpis pseudelpis, Blue Quaker Pithecops fulgens fugens, Scarlet Flash Rapala dieneces (Hewitson, 1878), Silver Royal Ancema blanka minturna, Jewelled Nawab Charaxes delphis delphis, Pallid Forester Lethe satyavati, Black Forester Lethe vindhya vindhya, Tailed Red Forester Lethe sinorix sinorix, Watson’s Bushbrown Mycalesis adamsoni, Dark Catseye Zipaetis scylax scylax, Dusky Diadem Ethope himachala, Wavy Maplet Chersonesia rahroides, Yellow Coster Acraea issoria issoria (Hübner, [1819]), Orange Awlet Burara jaina vasundhara, Sikkim White Flat Sereria sambara sambara Moore, [1866], Yellow-vein Lancer Pyroneura margherita, Yellow-veined Flat Mooreana trichoneura parlaya, Atkinson’s Bob Ametta atkinsoni (Moore, 1878), Dark Yellow-banded Flat Celaenorrhinus aurivittata aurivittata, Light Straw Ace Pithauria stramineipennis, Moore’s Ace Halpe porusporus, Northern Spotted Ace Thoressa cerata, and Yellow-Fringed Swift Caltoris aurociliata.