The seasonality of butterflies in a semi-evergreen forest: Gibbon Wildlife Sanctuary, Assam, northeastern India


Arun P. Singh 1, Lina Gogoi 2 & Jis Sebastain 3


1,2 Ecology & Biodiversity Conservation Division, Rain Forest Research Institute, P.O. Box # 136, Jorhat, Assam 785001, India

3 Research Centre in Botany, Sacred Heart College, Thevara, Kochi, Kerala 682013, India

1; (corresponding author), 2, 3


Abstract: A study spanning 3.7 years on the butterflies of Gibbon Wildlife Sanctuary GWS (21km2), a semi-evergreen forest, in Jorhat District of Assam, northeastern India revealed 211 species of butterflies belonging to 115 genera including 19 papilionids and seven ‘rare’ and ‘very rare’ species as per Evans list of the Indian sub-continent (Great Blue Mime Papilio paradoxa telearchus; Brown Forest BobScobura woolletti; Snowy Angle Darpa pteria dealbatahas; Constable Dichorragia nesimachus; Grey Baron Euthalia anosia anosia; Sylhet Oakblue Arhopala silhetensis; Branded Yamfly Yasoda tripunctata). The butterflies showed a strong seasonality pattern in this forest with only one significant peak during the post monsoon (September-October) when 118 species were in flight inside the forest which slowly declined to 92 species in November-December. Another peak (102 species) was visible after winter from March to April. Species composition showed least similarity between pre-monsoon (March-May) and post-monsoon (October-November) seasons. The number of papilionid species were greater from July to December as compared from January to June. The findings of this study suggest that the pattern of seasonality in a semi-evergreen forest in northeastern India is distinct from that of the sub-tropical lowland forest in the Himalaya. Favourable logistics and rich diversity in GWS points to its rich potential in promoting ‘butterfly inclusive ecotourism’ in this remnant forest.


Keywords: Conservation, eco-tourism, endemic, Papilionidae, rainfall, rare, semi-evergreen forest.



doi: | ZooBank:



Editor: Anonymity requested. Date of publication: 26 January 2015 (online & print)



Manuscript details: Ms # o3742 | Received 28 July 2014 | Final received 16 November 2014 | Finally accepted 29 December 2014



Citation: Singh, A.P., L. Gogoi & J. Sebastain (2015). The seasonality of butterflies in a semi-evergreen forest: Gibbon Wildlife Sanctuary, Assam, northeastern India. Journal of Threatened Taxa 7(1): 6774–6787;



Copyright: © Singh et al. 2015. 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: None.



Competing Interest: The authors declare no competing interests.



Author Contribution: APS carried out most of the sampling surveys, photography, identification, compilation and analysis of data and paper writing. LG assisted in sampling surveys, data recording, compilation and analysis for some trips. JS assisted in sampling surveys, data recording, compilation, data analysis for some trips and compilation of appendix



Author Details: Arun P. Singh is working on the ecology and conservation of biodiversity of the Himalaya and northeastern India with special reference to butterflies and birds. Presently, he heads the Ecology and Biodiversity Conservation Division, Rain Forest Research Institute (ICFRE), Jorhat. Lina Gogoi is an environmental science post graduate from Tezpur University, Assam had worked on weathering geochemistry of Lohit River, Dibang River and Dibru Saikhowa National Park. Also worked on ecological studies of butterflies in Arunachal Pradesh at the Rain Forest Research Institute for a short period. Currently working in Tezpur University as a project fellow in biochar related project. Jis Sebastian did her MSc in forestry from FRI University in Dehradun, Uttarakhand. She has working experience in Wildlife Trust of India and as JRF in the Rain Forest Research Institute on ecological studies of butterflies in Arunachal Pradesh. Currently perusing PhD research in botany at Sacred Heart College, Cochin, Kerala.



Acknowledgements: The authors are thankful to the officers and staff of the Assam Forest Department at the Gibbon Wildlife Sanctuary, Jorhat for their help from time to time and to the Director, Rain Forest Research Institute, Jorhat for providing necessary facilities. Thanks are due to Monsoon Jyoti Gogoi for sharing his records that have been added to the Appendix and to Riyaz A. Ahmed for assisting in a few of the field trips.








The northeastern region of India, that lies south of the Brahmaputra River, is part of the Indo-Burma biodiversity hotspot on the globe. It is located at the tri-junction of Indo-Chinese, Indo-Malayan and Palaearctic biogeographic realms exhibiting a profusion of habitats characterized by diverse biota with a high level of endemism (

More than 50% of the butterfly species found in India occur in the northeast, also called the “Papilionidae-rich zone” in the ‘Indo-Burma hotspot’ as per IUCN (New & Collins 1991). The high species richness and endemism make this an important region for conservation of biodiversity in India.


Study Area

The Gibbon Wildlife Sanctuary (GWS) 26040’–26045’N & 94020’–94025’E, lies in Jorhat District in upper Assam in northeastern India. It is today an isolated forest patch covering approximately 21km2 of mainly lush green ‘tropical semi-evergreen forest’ sparsely interspersed with ‘wet evergreen forest’ patches, classified as ‘Assam plains alluvial semi-evergreen forests (2B/C1a)’ (Champion & Seth 1968). Dipterocarpus retusus (Hollong) is the predominant element in the forest. The associated species are Ailanthus integrifolia, Altingia excelsa, Artocarpus chama, Castanopsis purpurella, Cinnamomum bejolgheta, Dysoxylum gobara, Mesua ferrea, Michelia champaca and Vatica lanceafolia (Baruah & Khatri 2010) with most of the tree species being utilized by the Western Hoolock Gibbon Hoolock hoolock here (Barua & Gogoi 2012). The altitudinal range of GWS varies between 100–120 m above sea level, while the average temperature ranges from 18.95­–27.9 0C, the average humidity varies between 64.5% and 94.5% and the annual rainfall of the study area being ~250cm. The sanctuary was carved out of Hollongapar Reserve Forest set aside in 1881 named after the dominant tree species - Hollong (Dipterocarpus retusus). Subsequently, more forest areas were added to this RF and by 1997 the total area of the Hollongapar RF increased to 2098.62ha. The Government of Assam declared this entire RF area as the Gibbon Wildlife Sanctuary in 1997. GWS is surrounded by mostly tea gardens and small villages. The Bhogdoi River flows from Nagaland (south) to Assam (north-west) and distinctly demarcates the eastern boundary of this sanctuary as a permanent physical barrier (Image 1). GWS was once contiguous with a large forest tract that extended to Dissoi Valley Reserve Forests of Nagaland in the south and are now separated by a vast stretch of tea gardens presenting a barrier in the effective migration of wildlife such as elephants (Bhattacharjee 2012). GWS today is still a home to many species of animals of global concern namely, Hoolock Gibbon Hoolock hoolock (Endangered; Brockelman et al. 2008); Capped Langur Trachypithecus pileatus (Vulnerable; Das et al. 2008), Slow Loris Nycticebus bengalensis (Vulnerable; Streicher et al. 2008), Pig-tailed Macaque Macaca leonina (Vulnerable; Boonratana et al. 2008), Stump-tailed Macaque Macaca arctoides (Vulnerable; Htun et al. 2008), Assamese Macaque Macaca assamensis (Near Threatened; Boonratana et al. 2008), Malayan Giant Squirrel Ratufa bicolour (Near Threatened; Walston et al. 2008), Asian Elephant Elephas maximus (Endangered; Choudhury et al. 2008), Leopard Panthera pardus (Near Threatened; Henschel et al. 2008), Large Indian Civet Viverra zibetha (Near Threatened; Duckworth, et al. 2008), Chinese Pangolin Manis pentadactyla (Endangered; Challender et al. 2014), as recorded by the author. Besides, many other species have also been listed in the sanctuary’s catalogue (Bordoloi 2010).

The published literature on the butterflies of the GWS is scanty. Senthilkumar et al. (2006) recorded 37 species from GWS. A blog by Abhijit Narvekar ( lists 31 species from GWS, recorded in May 2013. Besides these, there are no other published records of butterflies from GWS. The authors hereby report the results of a three and a half year study carried out by them in the GWS.











Twenty-eight sampling surveys covering all the months were carried out in Gibbon WS from 4 August 2010 to 26 April 2014. Sampling was carried out along forest trails up to 5m on both sides along a stretch of 3.5km from the village Melang Grant to the Gibbon Forest Rest House (FRH) and along the two parallel trails that goes from the FRH towards river Bhogdoi in the east (Fig. 1). The ‘Pollard walk’ (Pollard & Yates 1993) method was used for sampling butterflies. Sampling was carried out between 08.00hr to 15.00hr mostly on sunny days, but the sampling hours varied in different samplings from 1.5–3 hours. The taxa encountered were recorded in each sampling. The data on abundance, however, could not be recorded for each survey, but species occurring in exceptionally high numbers (peak abundance) were noted. A total of ~65 hours of sampling was carried out. Butterflies were identified from photographs and using field guides (Evans 1932; Wynter-Blyth 1957; Haribal 1992; Smith 1989 & 2006; Kehimkar 2008; Sondhi et al. 2013 and websites: and


Data Analysis

Data for the number of species recorded in each survey was pooled. Species accumulation curve was then plotted from the first to the last sampling to see the rate of species accumulation during the study period. The Sorensen’s similarity index or β was calculated to see the species similarity in butterflies between four different seasons meeting different seasons [pre-monsoon (March–May), monsoon (June–Sept), post-monsoon (October–November) and winter (December–February)]in this semi-evergreen forest.

β= 2c/ (S1+S2)

here, S1 = the total number of species recorded in one season/site

S2 = the total number of species recorded in different season/site

C = number of species common to both seasons/sites

The Sorensen’s similarity index (Sorensen 1948) is a very simple measure of beta diversity, ranging from a value of zero, where there is no species overlap between the communities to a value of one, when exactly the same species are found in both communities.

The seasonality of butterflies in GWS was then compared with trends available in other studies in other forest habitats in the Himalaya and the northeast to see the variation in this forest type.



Results and Discussions


Species richness

Amongst the 211 species belonging to 115 genera recorded during 28 sampling surveys (Appendix 1), 19 species were of the family Papilionidae. This suggests that species richness of the area could be as high as 257 species based on the family proportion model (Singh & Pandey 2004), by taking Papilionidae’s proportion as 7.4% of the total for northeastern India (Wynter-Blyth 1957). The present sampling thus represents about 82% of the species found in the study area. Families Lyceanidae and Hesperiidae proportions are less than those of the northeastern region, these two families are thus under-represented (Table 1) in the present surveys and there is a need to look for more species among these two families in GWS.


Species accumulation

An increasing trend in the species accumulation curve shows that new species were added during every sampling up to the last sampling at a prominently higher rate just after the monsoon rains (Aug–Sep) until pre-monsoon (March), every year (Fig. 2). The trend obtained during the last six samplings suggests that new species were still being discovered until the end (mainly Lycaenidae and Hesperiidae).



Maximum number of species were recorded during the ‘post monsoon’ season in the region (Fig. 3). The first peak in species richness (102 species) during March and April was smaller than the second peak in September to October (118) when most of the species are in flight in GWS. The two peak seasonal trends in butterflies is very typical of the Himalaya and northeastern India. In GWS, which is a semi-evergreen forest, the second peak is higher than the first peak, however. This pattern differs considerably from the sub-tropical lowland forests in Bhutan (Fig. 4; Singh 2012) lying between 100–220 m, where both the peaks are high but the first peak in April is slightly greater than the second peak in December (Fig. 4). The reason for the first peak being smaller than the second peak in GWS may be related to the pattern of rainfall here. The reason for the first peak being smaller than second peak higher in GWS may be related to the pattern of rainfall here. In GWS the onset of early rains is early in spring (from April), monsoons are less severe, there is short dry (moderate) winter in comparison to rains arriving relatively late in MayJune, severe monsoon and a longer winter season in Bhutan.


Species similarity among seasons

Sorensen’s similarity index between seasons varied from 0.25–0.55. This suggests that, the species composition varied in GWS all over the seasons of the year. However, the highest similarity was noticed between post-monsoon and autumn, post-monsoon and spring, winter and spring, spring and autumn, respectively. In other words from post-monsoon to spring the species composition in GWS showed much similarity. The similarity index was least between spring and pre-monsoon followed by monsoon and winter, respectively (Fig. 5). This suggests that major changes in species composition in the semi-evergreen forests occurs between these seasons, which may be related to the life history patterns of these butterflies. The number of species in flight during rainy season were few in comparison to the dry season.












Papilionidae species similarity of GWS with other semi evergreen forest areas in the region

GWS, a small forest, recorded 19 species of Papilionidae as compared to the other large forest tracts like in Jeypore-Dehing RF where 21 species of Papilionidae have been reported (Gogoi 2013). Four species (Great Zebra Graphium xenocles; Common Peacock Papilio polyctor; Common Windmill Atrophaneura polyeuctes and Lesser Batwing Atrophaneura aidoneus) found in Jeypore-Dehing RF (Gogoi 2013) were absent in GWS. This could be due to proximity and continuity of Jeypore RF with Himalayan foothills of Arunachal Pradesh from where these species come down and non-connectivity of GWS forest with the nearest hills in Nagaland and no freshwater mountain streams inside the GWS. Besides, 30 papilionids have been recorded in Garo Hills (Sondhi et al. 2013) of which 10 have not been recorded at GWS, but Garo Hills have diverse habitats under at least three forest types and a large altitudinal gradient when compared to GWS.

The Papiliondae species similarity between these three forests (Table 2) all having semi-evergreen forest component in common also have at least 53 percent papilionid species common among them.


Significant records

A dead female of the Great Blue Mime Papilio paradoxa telearchus, a rare species (Evan 1932), crushed by a vehicle on the forest road was recorded on 25 August 2012 on the road and later identified (Image 2). The female of this species are very rarely photographed as they mimic the female of the Magpie Crow Euploea radamanthus and thus overlooked. A male P.p. telearchus was photographed (Image 3) on 10 July 2013 feeding on the wet ground on the trail. This species also feeds on the nectar of Syzygium sp. flowers in September–October 2011 along with Great Archduke Lexias dirtea (Image 4), Blue-spotted Crow Euploea midamus; Stripe Blue Crow Euploea mulciber; Yellow-spot Jezebel Delias agostina; Red-spot Jezebel D. descombesi and Red-base Jezebel D. pasithoe. Brown Forest Bob Scobura woolletti woolletti Riley (Image 5), a rare species, was recorded on 20 February 2011 and 27 March 2011 was also a species with a distribution in the Naga Hills, Siam and Borneo (Evans 1932). Norman (1956), however, had recorded S.w. woolletti Riley from Sibsagar District of Assam that was previously also known from Manipur. The record of Snowy Angle, Darpa pteria dealbata on 4 August 2012 (Image 6), is the second photographic record of this species from India. Earlier, it had been recorded from the forests of Jeypore-Dehing in Assam between April 24 and 29, 2011, the distribution of the species being further south through Burma, Thailand, Laos, Malay Peninsula, Tioman, Borneo, Sumatra, Java, and Palawan, Phillipines in South-east Asia (Karthikeyan & Venkatesh 2011).The Constable, Dichorrhagia nesimachus (Image 7) a very rare species (Evans 1932) was recorded on three occasions, 15 April 2012, 7 December 2013 and 4 March 2014 and a male of Grey Baron, Euthalia anosia anosia (Image 8) another rare species (Evans 1932), on 15 April 2012 and 4 March 2014, both basking in the sunshine and on wet mud inside the forest. Sylhet Oakblue Arhopala silhetensis (Images 9,10) is another rare species (Evans 1932) that was recorded on several occasions (6 February 2011, 24 January 2013; 13 May 2013; April 2014), the species being found from Sikkim to North Myanmar. Tamil Oakblue Narathura bazaloides also a rare species was photographed on 9 October 2010 (Image 11) and April 2014 while Spotless Oakblue Arhopala fulla ignara Riley, a rare (Evans 1932) on April 2014. Branded Yamfly Yasoda tripunctata tripunctata (Image 12) is yet another rare species, which is also distributed from Sikkim to Myanmar, was recorded once on 25 October 2011.


















Being a remnant forest of 21km2, GWS supports a rich diversity of butterflies found in northeastern India. The seasonality and diversity of butterflies of asemi evergreen forest is unique from that of lowland subtropical forests of the lower Himalaya. Barua et al. (2010) have also found that rainfall has a strong correlation with the abundance of some papilionids in northeastern India besides a strong seasonality in continental South-east Asian butterfly assemblages. GWS, besides supporting butterfly diversity, also needs to be preserved as a gene bank biodiversity of flora and fauna (birds, mammals, herpetofauna, orchids, canes, bamboos, etc.) unique to northeastern India and functions as an island habitat for movement of large mammals and birds between larger protected areas in the landscape. Also, better accessibility and location of GWS with the national highway in the region, proximity to Jorhat town, lying in the plains and having a rest house, increases its potential for attracting tourists for - butterflyinclusive eco-tourism in a natural semi-evergreen forest habitat. Using local villagers as guides to generate livelihood for communities involved thereby reducing biotic pressure on one hand and conserving this magnificent forest on the other along, with the researchers and students, GWS can easily be taken up as a role model in conservation biology.







Barua, K.K., J.K.S. Slowik & M. Muehlenberg (2010). Correlations of rainfall and forest type with papilionid assemblages in Assam in northeast India. Psyche: A Journal of Entomology2010, Article ID 560396, 10pp;

Barua, K.N. & P.K. Khatri (2010). Floristic wealth, life formand biological spectrum of Gibbon Wildlife Sanctuary, Assam. Journal of Economic and Taxonomic Botany 34(1): 72–86.

Barua, K.N. & G. Gogoi (2012). Observations on feeding and lodging behaviour of Hoolock hoolock (Western Hoolock Gibbon) in Gibbon Wildlife Sanctuary, Assam. Journal of Nature and Environment 4&5: 29–35.

Bhattacharjee, S. (2012). The scenario of man-elephant conflict in Hoollongapar Gibbon Wildlife Sanctuary of Assam, India. International Journal of Scientific and Research Publications 2(8): 1–3.

Boonratana, R., M. Chalise, J. Das, S. Htun & R.J. Timmins (2008). Macaca assamensis. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Boonratana, R., J. Das, L. Yongcheng, S. Htun & R.J. Timmins (2008). Macaca leonina. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on20 January 2015.

Bordoloi, P.K. (2010). Gibbon Wildlife Sanctuary. Catalogue published by Jorhat Division, Assam. Genesis Printers, 6pp.

Brockelman, W., S. Molur & T. Geissmann (2008). Hoolock hoolock. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Challender, D., J. Baillie, G. Ades, P. Kaspal, B. Chan, A. Khatiwada, L. Xu, S. Chin, R. KC, H. Nash & H. Hsieh (2014). Manis pentadactyla. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Champion, S.H.G. & S.K. Seth (1968). A Revised Survey of The Forest Types of India. Manager of Pb.Govt. of India, New Delhi, 404pp.

Choudhury, A., D.K.L. Choudhury, A. Desai, J.W. Duckworth, P.S. Easa, A.J.T. Johnsingh, P. Fernando, S. Hedges, M. Gunawardena, F. Kurt, U. Karanth, A. Lister, V. Menon, H. Riddle, A. Rübel & E. Wikramanayake (IUCN SSC Asian Elephant Specialist Group) (2008). Elephas maximus. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Das, J., S. Molur & W. Bleisch (2008). Trachypithecus pileatus. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Duckworth, J.W., C. Wozencraft, W. Yin-xiang, B. Kanchanasaka & B. Long (2008). Viverra zibetha. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Evans, W.H. (1932). The Identification of Indian Butterflies-Second Edition. Bombay Natural History Society, Bombay, 464pp.

Gogoi, M.J. (2013). A preliminary checklist of butterflies recorded from Jeypore-Dehing forest, eastern Assam, India. Journal of Threatened Taxa 5(2): 3684–3696;

Haribal, M. (1992). The Butterflies of Sikkim Himalayas and their Natural History. Sikkim Nature Conservation Foundation. Sikkim, 217pp.

Henschel, P., L. Hunter, U. Breitenmoser, N. Purchase, C. Packer, I. Khorozyan, H. Bauer, L. Marker, E. Sogbohossou & C. Breitenmoser-Wursten (2008). Panthera pardus. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on20 January 2015.

Htun, S., R.J. Timmins, R. Boonratana & J. Das (2008). Macaca arctoides. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Karthikeyan, S. & V. Venkatesh (2011). “Snowy Angle Darpa pteria”. The Wild Wanderer, 07 September 2011 (Retrieved on 09/July 2013 from

Kehimkar I. (2008). The Book of Indian Butterflies. BNHS, Oxford University, Delhi Press, 497pp.

New,T.R. & N.M. Collins (1991). Swallotail Butterflies - An Action Plan for their Conservation. IUCN, Gland, Switzerland.

Norman, T. (1956). Notes on the Lepidoptera of Assam-III. Further additions to the Indian list and other notes. Journal of the Bombay Natural History Society 53: 738–740.

Pollard, E. & T.J. Yates (1993). Monitoring Butterflies for Ecology and Conservation. Chapman & Hall, London, 274pp.

Senthilkumar, N., S. Trivedi, P.K. Khatri, N.D. Borthakur & N.J. Borah (2006). Butterflies of Gibbon Wildlife Sanctuary, Assam: a preliminary survey. Annals of Forestry 14(1): 86–91.

Singh, A.P. (2012). Lowland forest butterflies of the Sankosh River catchment, Bhutan. Journal of Threatened Taxa 4(12): 3085–3102;

Singh, A.P. & R. Pandey (2004). A model for estimating butterfly species richness of areas across the Indian subcontinent: species proportion of family Papilionidae as an indicator. Journal of the Bombay Natural History Society 101(1): 79-89.

Smith, C. (1989). Butterflies of Nepal (Central Himalaya). Tecpress Service L.P., Bangkok, 352pp.

Smith, C. (2006). Illustrated Checklist of Nepal’s Butterflies. Craftman press, Bangkok, 129pp.

Sondhi, S., K. Kunte, G. Agavekar, R. Lovalekar & K. Tokekar (2013). Butterflies of the Garo Hills. Samrakshan Trust (New Delhi), Titli Trust (Dehradun), and Indian Foundation for Butterflies (Bengaluru), xvi+200pp.

Sorensen, T.A. (1948). A method of establishing groups of equal amplitude in plant sociologybased on similarity of species content, and its application to analyses of the vegetation on Danish commons. Kongelige Danske Videnskabernes Selskabs Biologiske Skrifter 5: 1–34.

Streicher, U., M. Singh, R.J. Timmins & W. Brockelman (2008). Nycticebus bengalensis. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on20 January 2015.

Walston, J., J.W. Duckworth & S. Molur (2008). Ratufa bicolor. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 20 January 2015.

Wynter-Blyth, M.A. (1957). Butterflies of the Indian Region. Bombay Natural History Society, Bombay, 523pp.