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WELCOME TO SIKKIM
... the Land of Mystical Splendor !

Of the 1,400 species of butterflies found in the Indian Sub-continent almost 700 species  have been recorded from Sikkim.                                                                                           
 

History of butterfly study and collection from Sikkim 
First ever mention of Sikkim butterflies in the modem literature is in the the Hooker's Himalayan Journals. 

Leaving the forest, the path led along the river(Rangeet) bank, and over the great masses of rock which strewed its course. The beautiful India rubber Fig was common, as was Bassia butyracea the 'Yelpote' o f the Lepchas, from the seeds they express a concrete oil, which is received and hardens in bamboo vessels. On the forest skirts, parasitical orchids and ferns bounded, the Chaulmoogra, whose fruit is used to intoxicate fish, was very common; as was an immense mul berry tree, that yields a milky juice and produces a l ong green sweet fruit. Large fish, chiefly Cyprinoid, were abundant in the beautifully clear water of the river. But by far the most striking feature consisted in the amazing quantity of superb butterflies, large tropic- al swallowtails black, with scarlet or yellow eyes on their wings. They were seen everywhere, sailing majes tically through the still hot air, or fluttering from one scorching rock to another, and especially loving to settle on the damp sand of the river edge; where they sat by thousands, with erect wings, balancing themselves with a rocking motion, as their heavy sails inclined them to one side or other; resembling a crowded fleet of yachts on a calm day. Such an entomological display cannot be surpassed. 

- Joseph Dalton Hooker May 1848. Himayalan Journals Vol. I, p. 143 Published 1855

He also writes about high altitude butterflies as follows: "During my ten days stay at Zemu Samadong (3,000 m), I formed large collection of insects many were new, beautiful and particularly interesting from belonging to types whose geographical distribution is analogous to that of the vegetation. The caterpillars of the swallowtail butterfly (Papilio machon) was common, feeding on umbelliferous plants as in England: and a Sphynx (like S. eurphorbiae) was devouring the euphorbias. The English Cynthia Cardui (the Painted Lady) was common, as were 'sulphurs', 'marbles' Pontia (whites) 'blues' and Thecla of British aspect, but foreign species. Among these, tropical fOnDS were rare except one fine black swallowtail." (presumably P. arcturus).

First ever serious report on the butterflies of Sikkim was published by H. J. Elwes (1880) in the Proceedings of the Zoological Society of London. Later, the same author along with Otto Moller (1888) published additions to the butterflies of Sikkim in the Transactions of Entomological Society of London. In the same period L. De Niceville, who was with the natural history section of the Indian Museum in Calcutta also made several trips to Sikkim and its neighbourhood and wrote a series of papers in the Journal of Royal Asiatic Society of Bengal (1881, 1882, 1883 and 1885). Almost at the same period the Gazetteer of Sikhim (1890) was brought out in which G. A Gammie and De Niceville have recorded about 631 species of butterflies found in Sikkim, including those which are found in Darjeeling, Buxa and Bhutan as the area was contiguous with Sikkim state and also the vegetation was similar to that of Sikkim. But how many of these butterflies have become synonyms of some of the other butterflies mentioned in the text. A few other authors like G. W. V. DeRhe-Philipe (1911), H. C.Tytler (1915) and F. M. Bailey (1911) have mentioned about few of the butterflies of Sikkim in their papers in the Journal of Bombay Natural History Society, while describing for other areas. D. F. Sanders (1947) who did extensive collections in Sikkim around 1940s has also published a paper in Journal of Bombay Natural History Soc., with notes on Sikkim butterflies and their status, but a major list of Sikkim butterflies maintained by him, was available to M. A. Wynter-Blyth and the same has been incorporated in latter's book. 

Other than these publications, the museum collections of butterflies of Sikkim are distributed all over the world, but the major collections are in Natural History Museum(NHM) in London. I had access to the Museums of Bombay Natural History Society (BNHS), Forest Research Institute (FRI), Debra Dun, ICAR Museum at PUSA New Delhi and Natural History Museum in London and have compiled collection data for over 1500 specimens of about 300 species. The data for those species which are currently common in Sikkim as per our observations have not been compiled. The ZSI museum at Calcutta was so visited but I did not study them except for a cursory glance. 

On the basis of these museum collections it can be concluded that most of the Hooker's collections were carried out between 1880 to 1920. The major collection from this area was by Otto. Moller who was stationed in Darjeeling and had employed local collectors for collection and used to supply these specimens to various European collectors like Rothschild, Fruhstorfer, Godwin-Salvin etc. His collections are now largely in NHM as most of these above collectors have donated their collections to NHM. G. C. Dudgeon collected extensively from 1889-1900 from Sikkim. Other major collectors are R. P. Bretaudeau and C. Bretaudeau who collected mostly from Lachen-Lachung valleys and their collections are seen in NHM. Various veteran collectors of those days like C. T. (whites) Bingham, H. C.

Tytler, F. M. Bailey, F. Hannyngton and W. H. Evans also visited this area several times. Evans visited Sikkim between 1894-1928 at least five times. Earlier two Everest Expeditions of 1922 and 1924, which entered Tibet via Sikkim, had sent naturalist climbers like Maj. Hingston who with the help of local collectors collected a large number of specimens from Sikkim particularly from the higher altitudes which are now in the custody of NHM and the report about the same was published in technical report of the expeditions by Alpine Oub, but the same was not available to me as the library of the Alpine Club was under renovation. B. C. Ollenbach also collected between 1914-1922 from Sikkim and his collections are seen in FRI museum.
The unfortunate thing about these collections is that most of the collectors mention 'Sikkim' as the place of collection and no exact locations or altitudes are mentioned. One reason for this may be that the state of Sikkim was sparsely populated, not so developed, had very few villages with very small population. Even Gangtok, the capital of Sikkim was not much bigger than a present modem village. The places often mentioned in the collections are valleys of rivers like Rangeet, Teesta, Lachen and Lachung, Also the specific places mentioned are Gangtok, Dikchu, Tendong, Thangu, Senchal, Singhal, Rhenok, Troomling, Kupup, AD, Gnathong and Karponang. Another interesting observation from these data is that most of the collectors were not residents of Sikkim but the visitors and had gone specifically for natural history collections. So most of the information available is from March-May and from August- November when the weather is good and very little information is available for June-July (months of the heavy rains) and almost no information is available for December-March except for a small collection by Usha and her friends in December in the recent years.

My own observation limits to seven short visits to Sikkim during August, September-November, March, April of various years and amounts to about 250 species of which many are single sightings. I have tried to cover as much area as possible to survey various kinds of habitat found in Sikkim.

The following places were visited. 
# ES = East Sikkim; NS = North Sikkim; WS = West Sikkim; SS = South Sikkim
 

On the basis of these collections and literature I have made a check-list of 689 butterflies and easily ten more could be added,

Biodiversity and Endemism
Although Sikkim is one of the smallest Himalayan states, with an area of 7,299 sq. km. the biodiversity has given Sikkim an unique status. For example, within 30 km of Tholung Valley the altitude rises from 600 m to 5,500 m. Due to this steepness of the mountain and the geographical and climatic conditions, the floral and faunal diversity ranges from tropical species to high altitude cold desert species.
Of total of about 1,400 butterflies recorded from the Indian Sub-continent almost 50% of butterflies are recorded from Sikkim. Of the total area of Sikkim 40% (North Sikkim) is almost inhabitable and is covered with snow for about 4-8 months to perpetual snow and unsuitable for any life. About 30% of the total area of Sikkim which occupies the altitudinal zone from about 200-1,800 m is represented by about more than 75% species butterflies of Sikkim. Remaining species are found in the in-between zone and some of them overlap all the zones.
The subfamily Amathusiinae occurs mainly below 900 m. The region between 600-1,800 m is occupied by the typical hilly region butterflies. The Lycaenidae and Hesperiidae are highly diversified. Many of the type specimens of Hesperiids have been collected from Sikkim and are in NHM. The nymphalids and danaids are abundant in this region. They include butterflies like the Barons, Pansies, Sailers, Sergeants, Tigers, Crows etc. These butterflies have affinity to Oriental fauna. The Swallowtails also abound this region. Pieridae is represented by Gulls, Puffms, Jezebels and Orangetips.
The zone between 1,800-3,500 m has butterfly fauna typical of temperate zones and have affinity to the Palaearctic fauna. The nymphalids which are found in this region are the Admirals, Tortoiseshells, Silverstripes and Silverspots. Hardly any danaids except for the Chestnut Tiger, occur in this region. Lycaenids mostly consist of the subfamilies Lyaceninae, Theclinae and Polyommatinae- Hairstreaks, Sapphires, Hedge Blues etc. Lybithinae occurs mostly in this zone. Punches and Judies are also seen. But the most diversified is the subfamily Satyrinae, particularly the tribes Lethini and Satyrini. Foresters, Walls, Golden and Silver Forks are numerous. As many as 36 species of tribe Lethini are found in Sikkim. Of the Swallowtails very few larger butterflies occur in this region and include the Krishna and Blue Peacocks. The Yellow Swallowtail in Sikkim has been recorded only from the altitudes above 3,000 m, although it occurs up to 2,000 m in other parts of Himalaya.
The zone beyond 3,000 m is occupied by a very few specialised species which are adapted to harsh climatical conditions and have affinity to the Palaearctic fauna. They include Apollos and Yellow Swallowtail of the Papilionidae. The Clouded Yellows of Piriedae, the Silverstripes and Silverstreaks and the Admirals of Nymphalidae and a very few species of blues like Chumbi Green Underwing, Azure Mountain Blue etc. also occur. Satyrinae is represented by the tribe Satyrini consisting of the Arctic and Mountain Arguses and the Great Satyr.
Table I List comparing butterfly diversity in Sikkim and its neighbouring oriental region
 

A few butterflies on account of being polyphagus are found from sea level to the high mountains up to about 4,500 m. They are the Indian and the Large Cabbage Whites, Tortoiseshells, Indian Red Admiral, Painted Lady, Dark Clouded Yellow etc.
The Geographic position, i.e. Sikkim is bound by high mountains of more than 4,000 m on three sides, has led to isolation of the the' population occurring in Sikkim. Probably due to this reasons many of them have become distinct subspecies and forms.
There are many Oriental species which do not occur west of Sikkim. The reason for this may be that the great North-South ridge of the Khangchenzonga spur and Singalila act as barrier for dispersal of the species. Similarly many Palaearctic species like Lassiomata, Hipparchia and Dallacha have not been recorded east of Nepal.
Many of the subspecies are known only from Bhutan and Sikkim. Infact the following species have been so far recorded only from Sikkim -Lethe trisigmata, Lethe atkinsoni, and that too from high altitudes of Lachen and Lachung Valleys. But this does not necessarily mean they are endemic to Sikkim only as the surrounding regions like Bhutan, Arunachal Pradesh, South Tibet have similar biodiversity. But hardly these areas have been explored in detail for butterfly fauna also a very few records are available from these regions in last hundred years.

Current status
Compared to earlier records definitely there is a great reduction in numbers as well as species. The main reasons for this is increase in human population and developmental activities and urbanisation.

The lower valleys particularly in those areas which are less disturbed still have a great number of species. The best altitude to observe butterflies is between 900-1,800 m. Most of the swallowtails, nymphalids are abundant here.

The Amatheusiinae needs a special survey to assess the presence of these species in Sikkim as most of the moist bamboo forest habitats are lost.
The best places for looking out for butterflies is the Rangeet Valley and lower altitudes of the Teesta Valley. In the list the places marked with an asterix are very fruitful areas for the butterflies.

The exact current status for most of the species cannot be assessed as the total observation period of my visit was about 1,500 hr. The months of visits were also mostly September - November , except for one visit in August to higher altitudes and one in March-April. Also during my earlier few visits not much of observation on Lycaenids, Hesperiids and Satyrins were carried out as I was not very conversant with these insects. So unless a thorough study in all the seasons is carried out it is not possible to really assess the status, as many butterflies are single brooded or breed only at some particular time of the year. So this treatise is an attempt to help the interested reader to start the observations and send in their observations. May be after a few years of vigorous data collection, particularly by the people stationed in Sikkim itself, we can come to some conclusion and I hope by that time it would not be too late to carry out any protection measures.