A preliminary checklist of butterflies ( Lepidoptera : Rhophalocera ) of Mendrelgang , Tsirang District , Bhutan

Acknowledgements: The authors are highly thankful to Mr. Dorji Wangchuk, Ex-Principal, Mendrelgang Middle Secondary School for giving us permission to conduct the study. Sincere thanks to Mr. Peter Smetacek, Butterfly Research Centre, Bhimtal (India), Mr. Monsoon Jyoti Gogoi, Assam University, Silchar (India) and Mr. Saito Motoki, The Butterfly Society of Japan, Tokyo (Japan) for providing help during the identification of the specimens and their valuable suggestions. Thanks to Mr. Sonam Dorji, Mountainhawk Adventures (Thimphu, Bhutan) for providing photographs and Mr. Shikhin B. Kolhe, Ahmednagar College, Ahmednagar (Maharashtra, India) for corrections and suggestions during the preparation of manuscript. Bhutan forms a part of the eastern Himalaya Biodiversity Hotspot which covers parts of Nepal, Bhutan, the northeastern Indian states of West Bengal, Sikkim, Assam, and Arunachal Pradesh, southeastern Tibet (Autonomous Region of China), and northern Myanmar (http://www.conservation.org/where/priority_areas/ hotspots/asia-pacific/Himalaya/Pages/default.aspx). Bhutan, along with northeastern India, is the meeting place of the central Asia, and Chinese subdivision of the palearctic region and hence considered very rich in terms of lepidopteran diversity. The country has a variety of forest types, from tropical evergreen forests to alpine meadows, which provide a vast range of habitat niches for butterflies (Wangdi et al. 2012). Evans (1932) identified 962 taxa of butterflies from northeastern India from Sikkim, Assam, Manipur, Meghalaya, Nagaland, Mizoram to northern Myanmar. Wynter-Blyth (1957) listed 835 species of butterflies from northeastern India including Sikkim, Bhutan and Assam up to Chittangong. However, there is paucity of information on butterflies of Bhutan. One estimate puts the range between 800– 900 species with the largest number being found in the sub-tropical zone of Bhutan (van der Poel & Wangchuk 2007). Previous studies on the butterfly fauna of Bhutan (e.g., Bingham 1905; Talbot 1939, 1947; Wynter-Blyth 1957) are not comprehensive. More recent studies by van der Poel & Wangchuk (2007), Singh (2012), Wangdi et al. (2012), Wangdi & Sherub (2012), have indicated the diversity and uniqueness of butterflies found in Bhutan. However, there are no records of butterflies from Mendrelgang in Tsirang District. The nearest records comprise the study carried out by Singh (2012) in the lowland forests of the Sankosh River catchment lying below 200m in the western-most corner of this district. The present study therefore provides baseline Abstract: The survey was conducted to prepare a preliminary checklist of butterflies of Mendrelgang, Bhutan. Butterflies were sampled from February 2012 to February 2013 to assess the species richness in a degraded forest patch of a sub-tropical broadleaf forest. This shortterm study recorded 125 species of butterflies in 78 genera from five families. Of these, Sordid Emperor Apatura sordida Moore, Blackveined Sergeant Athyma ranga ranga Moore, Sullied Sailor Neptis soma soma Linnaeus, Blue Duke Euthalia durga durga Moore, Pea Blue Lampides boeticus Linnaeus and Chocolate Albatross Appias lyncida Cramer are listed in Schedule II of the Indian Wildlife (Protection) Act (IWPA) 1972. This study provides the baseline data of butterfly species richness of Mendrelgang.

Bhutan forms a part of the eastern Himalaya Biodiversity Hotspot which covers parts of Nepal, Bhutan, the northeastern Indian states of West Bengal, Sikkim, Assam, and Arunachal Pradesh, southeastern Tibet (Autonomous Region of China), and northern Myanmar (http://www.conservation.org/where/priority_areas/hotspots/asia-pacific/Himalaya/Pages/default.aspx).Bhutan, along with northeastern India, is the meeting place of the central Asia, and Chinese subdivision of the palearctic region and hence considered very rich in terms of lepidopteran diversity.The country has a variety of forest types, from tropical evergreen forests to alpine meadows, which provide a vast range of habitat niches for butterflies (Wangdi et al. 2012).Evans (1932) identified 962 taxa of butterflies from northeastern India from Sikkim, Assam, Manipur, Meghalaya, Nagaland, Mizoram to northern Myanmar.Wynter-Blyth (1957) listed 835 species of butterflies from northeastern India including Sikkim, Bhutan and Assam up to Chittangong.However, there is paucity of information on butterflies of Bhutan.One estimate puts the range between 800-900 species with the largest number being found in the sub-tropical zone of Bhutan (van der Poel & Wangchuk 2007).Previous studies on the butterfly fauna of Bhutan (e.g., Bingham 1905;Talbot 1939Talbot , 1947;;Wynter-Blyth 1957) are not comprehensive.More recent studies by van der Poel & Wangchuk (2007), Singh (2012), Wangdi et al. (2012), Wangdi & Sherub (2012), have indicated the diversity and uniqueness of butterflies found in Bhutan.However, there are no records of butterflies from Mendrelgang in Tsirang District.The nearest records comprise the study carried out by Singh (2012) in the lowland forests of the Sankosh River catchment lying below 200m in the western-most corner of this district.The present study therefore provides baseline 5756 data of the butterfly fauna of a part of Tsirang District.

Study Area
Mendrelgang is a division of Tsirang District, Bhutan situated at 27 0 02'N & 90 0 10'E (Image 1) between 700-1750 m elevation, covering an area of about 15km 2 .The region has a temperate climate with the temperature ranging between 20 0 C and 35 0 C. The cold season extends from October to March, followed by summer season from April to June and rainy season from June to September (NSB 2010).The forest type found in this region is subtropical broad-leaf forest in the lower valley and mixed Chir Pine (Pinus roxburghii, Sarg.) forest at higher altitude (Image 2).

Material and Methods
Butterfly fauna of Mendrelgang was surveyed during February 2012 to February 2013.The survey was done every Sunday between 10.00-16.00hr on the forest trails, hill streams, near residential areas and open fields.The butterflies were photographed in their natural habitat.The specimens which were difficult to identify in the field were collected as voucher specimens using a hand net.Identifications were carried out with the help of Evans (1932), Talbot (1947), photographic guides of Smith (2006), van der Poel & Wangchuk (2007), Kehimkar (2008) and internet references (www.flutters.org;www.ifoundbutterflies.org).Photographs of species that were still left unidentified or were taxonomically challenging were sent to Peter Smetacek, Butterfly Research Centre, Bhimtal (India), Mr. Saito Motoki, The Butterfly Society of Japan (BSJ), Tokyo (Japan) and Mr. Monsoon Jyoti Gogoi, Assam University, Silchar (India) for confirmation.

Results and Discussion
April to November was found to be best months for recording butterflies in Mendrelgang.Altogether, a total of 125 species of butterflies were recorded (Images 3-127).The recorded species belong to 78 genera representing five families and are illustrated in Appendix 1.The present study further appends 45 species of butterflies to the known list of butterflies reported by van der Poel & Wangchuk (2007), Singh (2012), and Wangdi et al. (2012, 2013) shows the importance and the urgent need to protect the habitat of these species of butterflies in subtropical broadleaf forest of Mendrelgang.Further notes on selected species are appended below.
Banded Treebrown Lethe confusa confusa Aurivillius (Image 15): Many individuals were encountered from March to October in degraded forest of Mendrelgang (1,100m).They mainly prefer the shaded areas under the forest.The species is reported from other locations of Bhutan and is common (Singh 2012;van der Poel & Wangchuk 2007).The habitat of the species was from Murree to Sikkim, Assam and Burma and was common (Talbot 1947).

Straight-Banded Treebrown Lethe verma sintica
Fruhstorfer (Image 19): Many species were encountered in the orange orchards and forest clearings from April to October in the study area.The species was very common in Bhutan and also reported from other parts of Bhutan (Singh 2012;van der Poel & Wangchuk 2007).
The habitat of the species is from Sikkim to Assam and northern Burma (Talbot 1947).The species is also recorded from Nepal at 2,133.6m and is rare as per Gough (1935).
Lilacine Bushbrown Mycalesis francisca sanatana Moore (Image 22): Many individuals were encountered in October and November 2012 under the orange trees and forest undergrowth.They show weak flight pattern and are seen sipping exudes from the bark of orange trees.The species occurs from Kulu-Burma and were not rare (Evans 1927;Talbot 1947).However, the species is distributed through Himachal Pradesh to Arunachal Pradesh, northeastern India, Nepal, Bhutan, Bangladesh, Burma (Myanmar) and is not rare (Kehimkar 2008).
Jungle Brown Orsotriaena medus medus Fabricius (Image 24): One individual was photographed in December 2012 near a forest stream at Mendrelgang (1,179m).They remain in the shade and fly close to the ground.This species has been reported from subtropical lowland forests of Bhutan along the Sankosh River (118-220 m) (Singh 2012).The subspecies is distributed from Nepal and Sikkim to Burma and Andaman Islands and was common as per Talbot (1947).
Blackvein Sergeant Athyma ranga ranga Moore (Image 36): One male was encountered near a forest stream in August (8.viii.2012)and one female was encountered in December (16.xii.2012).The species was also encountered by Singh (2012) in the lowland forest of Bhutan along Sankosh River.The species is rare and distributed from Sikkim to Burma (Evans 1927).The species is protected under Schedule II of IWPA, 1972 in India.The status of this species is unknown in Bhutan.
Blue Duke Euthalia durga durga Moore (Image 37): Many individuals were encountered from July to October in the study area.Often seen feeding on bird droppings and rotten fruits.They fly above the canopy and sit on the upper surface of the leaves with open wing.It was also reported from Eastern Bhutan (van der Poel & Wangchuk 2007).The subspecies was distributed through Sikkim-Abors and was rare as per Evans (1927).The species is protected under Schedule II of IWPA, 1972 in India.The status of this species is unknown in Bhutan.
Scarce White Commodore Sumalia zulema Doubleday (Image 44): One individual was encountered in August (19.viii.2012) of around 1,179m near a water tap.The species has been photographed and sighted recently from East Sikkim District and Namdapha (Arunachal Pradesh) (http://www.ifoundbutterflies.org/sp/1091/Sumalia-zulema).The species was distributed through Sikkim-N.Burma and was very rare as per Evans (1927).The status of this species is unknown in Bhutan.
Indian Purple Emperor Apatura ambica ambica Kollar (Image 48): One female and one male were encountered in July (17.vii.2012) at noon chasing each other on the black topped road.Another female was also spotted in the same month (29.vii.2012)basking on rocks.This species has been reported from sub-tropical lowland forests of Bhutan along the Sankosh River (118-220 m) (Singh 2012) and eastern Bhutan (van der Poel & Wangchuk 2007).It is a fast flier and often settles on damp rocks with open wing.The subspecies occured in Kashmir-Dawnas and was not rare (Evans 1927).
Sordid Emperor Apatura sordida Moore (Image 49): This species is commonly seen in the month of October (14.x.2012October (14.x. , 20.x.2012October (14.x. , 29.x.2012).Several individuals were seen sipping on exudes of orange tree along with other butterflies like H. marathus and M. francisca sanatana.It was found to be locally common (1,179m) near the orange orchards.The species is on the wing from April to November and flies at low elevation around 2,000m (Naga Hills) (Kehimkar 2008).The species is reported from Manipur throughout the summer and autumn.A single specimen was also collected on Silchar road in October and was extremely local (Tytler 1915).The species is protected under Schedule II of IWPA, 1972 in India but the status of this species is unknown in Bhutan.
Pasha Herona marathus marathus Doubleday (Image 50): Many individuals were seen commonly from July-October, sipping on exudes of orange tree along with other butterflies like A. sordida and M. francisca sanatana.The subspecies was not rare and distributed from Sikkim-Shan States (Evans 1927).
Siren Hestina persimilis Westwood (Image 52): One female was encountered feeding on flower of Callistemon species (Bottle Brush plant) at Mendrelgang middle secondary school campus (1179m) in October (17.x.2012).The species is distributed through India (Himachal Pradesh to Arunachal Pradesh, northeast, Orissa), Nepal and Bhutan (Kehimkar 2008).Recently, it has been reported from Jones Estate (Uttarakhand) where it is quite common (Smetacek 2012), rare in the study area.The species is protected under Schedule II of IWPA, 1972 in India but the status of this species is unknown in Bhutan.
Red Helen Papilio helenus helenus Linnaeus (Image 72): Many individuals were encountered nectaring on flowers of Asclepias curassavica (Scarlet Milkweed) in October.The species was common up to 2100m and distributed from Mussoorie to Burma, extending also to Siam and the Malay Peninsula (Talbot 1939).
Common Birdwing Troides helena cerberus Felder & Felder (Image 76): One female was encountered feeding on the nectar of Callistemon species (Bottle Brush plant) at Mendrelgang middle secondary school campus (1,179m) in September (23.ix.2012).The species was common up to 914.3m from spring until autumn and was distributed from Sikkim to Orissa and Burma (Talbot 1939).It also occurs in Tong-king, the Malay Peninsula, the Natuna Islands and Borneo.
Green Oakblue Arhopala eumolphus eumolphus Cramer (Image 95): One female was encountered in Mendrelgang during the field study near a forest stream (9.xii.2012).It is rare and probably first report of this species from Bhutan.The species was reported from Sikkim, Nepal, Assam and not rare as per Evans (1932).
Jyntea Hedge Blue Celastrina argiolus jynteana de Niceville (Image 106): One individual was encountered once on an abandoned rice field near forest in March (10.iii.2012).The subspecies was distributed from Sikkim-Burma and was common (Evans 1927).
Water Snow Flat Tagiades litigiosa litigiosa Moschler (Image 121): One individual was encountered near a forest stream in March (29.iii.2012) and another individual was also encountered at the same place in September (10.ix.2012).Mainly prefers shade in moist patches close to water.It flies around and often returns to same perch or settles on undersurface of leaf.The subspecies was distributed from Sikkim to Burma, Andamans, western China, Siam, Hainan and was not rare (Evans 1927).
Black-veined Redeye Matapa sasivarna Moore (Image 124): One individual was encountered nectaring on Carica papaya flower near a residential house in October (20.x.2012).Singh (2012) also reported this species from subtropical lowland forests of Bhutan along the Sankosh River (118-220 m) but not reported from Trashiyangtse Valley, eastern Bhutan (1200-2700 m) (Wangdi et. al. 2012) Photograph showing degraded forest habitat along with agricultural land in study area, Mendrelgang.
. The most significant results were the sightings of Apatura sordida Moore, Athyma ranga ranga Moore, Neptis soma soma Linnaeus, Euthalia durga durga Moore, Lampides boeticus Linnaeus and Appias lyncida Cramer which were included in Schedule II of the Indian Wildlife (Protection) Act (IWPA) 1972 but none of the species are mentioned in the Forest Nature and Conservation Act of Bhutan 1995 or the IUCN Red List of Threatened Species (IUCN 2010).The sightings of rare species like Siren Hestina persimilis Westwood, Spotted Palmfly Elymnias malelas malelas Hewitson, Straight-Banded Treebrown Lethe verma sintica Fruhstorfer, Blackvein Sergeant Athyma ranga ranga Moore, Blue Duke Euthalia durga durga Moore, Scarce White Commodore Sumalia zulema Doubleday, etc.

5759 Appendix 1. Preliminary checklist of butterflies recorded by the authors during February 2012 to February 2013 in Mendrelgang division of Tsirang District (Bhutan)
. The habitat of this species is from Sikkim to Burma extending towards Malay Peninsula,