Rediscovery of the federally protected Scarce Jester Butterfly Symbrenthia silana de Nicéville, 1885 (Nymphalidae: Nymphalinae)
from the Eastern Himalaya and Garo Hills, northeastern India
Krushnamegh Kunte
FAS Center for Systems Biology, Harvard University, 52 Oxford
St, Cambridge, MA 02138, USA
Email: KKunte@cgr.harvard.edu
Date of publication (online): 26 May 2010
Date of publication (print): 26 May 2010
ISSN 0974-7907 (online) | 0974-7893 (print)
Editor: Zdenek Faltynek Fric
Manuscript
details:
Ms # o2371
Received 27
December 2009
Finally
accepted 04 April 2010
Citation: Kunte, K. (2010). Rediscovery of the
federally protected Scarce Jester Butterfly Symbrenthia silana de Nicéville, 1885 (Nymphalidae: Nymphalinae) from the Eastern
Himalaya and Garo Hills, northeastern India. Journal of Threatened Taxa 2(5): 858-866
Copyright: © Krushnamegh Kunte 2010. Creative
Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this
article in any medium for non-profit purposes, reproduction and distribution by
providing adequate credit to the authors and the source of publication.
Author
Details: Krushnamegh
Kunte is a Post-Doctoral Research Fellow at the FAS Center for Systems
Biology, Harvard University. He has
studied Indian butterflies for 20 years, and is now extensively surveying
butterfly diversity in the Eastern Himalaya. He is author of the book, Butterflies of Peninsular India (2000,
Universities Press, Hyderabad).
Acknowledgements: I am indebted to Usha Lachungpa
(Senior Research Officer, Wildlife, in the Department of Forest, Environment
& Wildlife Management, Govt. of Sikkim) for making
all the local arrangements and for guidance on my first two visits to Sikkim.
Logistical support from the Department of Forest, Environment & Wildlife
Management, Govt. of Sikkim, is deeply appreciated, with special thanks to the
following officials: S.T. Lachungpa (IFS, PCCF cum Secretary, Forests), N.T.
Bhutia (IFS, APCCF cum CWLW), Thomas Chandy (IFS, CCF – Territorial), C.S. Rao
(IFS, CF – Territorial), C. Lachungpa (IFS, CCF – Land Use & Env.), H.P.
Pradhan (IFS, CCF – WL), Monalisa Das (IFS, DFO – Territorial, North),
Catherine Lepcha (SFS, ACF – Territorial, North), and Brijendra Swaroop (IFS, DFO
– Territorial, West). Thanks to Ullasa Kodandaramaiah, Arjan Basu Roy,
Rudraprasad Das and Kedar Tokekar for providing very valuable additional
records and photographs of S. silana(photographs, maps and figures not credited to others are by Krushnamegh
Kunte). Thanks to Deepa Agashe for useful comments on the manuscript, and Scott
Walker, Max Overton, Chandan Jyoti Gogoi, Niranjan Bhagobaty and Ashwin Baindur
for their assistance in preparing the map in Image 2 and in finding exact
positions of old localities. Specimens depicted in Image 1 are from the Museum
of Comparative Zoology (MCZ), Harvard University; thanks to Rod Eastwood for
his assistance in locating and photographing these specimens. The field trip on
which the first S.
silana sighting was made was partly funded
by the American Philosophical Society’s Lewis and Clark Fund for Exploration
and Field Research.
Abstract:Symbrenthia silana, the Scarce Jester Butterfly
(Nymphalidae: Nymphalinae), is legally protected under Schedule-I of India’s
Wildlife (Protection) Act, and listed as Vulnerable to extinction following
IUCN’s Red List Categories and Criteria in the Red Data Book of Indian
butterflies. However, the species is so
rare that it has not been seen for ca 90 years and nothing is known about its
status, habitat and populations. Here I report rediscovery of the species from
Sikkim, Namdapha Tiger Reserve and Nokrek National Park in the Eastern Himalaya
and Garo Hills of northeastern India. The first pictures of live butterflies
are presented along with information on the habits and habitat of the species,
and a discussion of its status as a vulnerable species.
Keywords: Biodiversity hotspots, Eastern Himalaya, Garo Hills, Symbrenthia, Wildlife Protection Act,
wildlife conservation
INTRODUCTION
The Oriental butterfly genus Symbrenthia Hübner, 1819 (Nymphalidae:
Nymphalinae: Nymphalini) is represented by S. hippoclus Cramer, 1779 as its type species (Hemming 1967). The genus includes 10-15 species distributed
from the Western Himalaya in India to southern China, and southward to
Sundaland, the Philippines and New Guinea (Smith 1989; Corbet et al. 1992;
Huang 1998; Bascombe et al. 1999; Huang 1999, 2000; Fric et al. 2004; Huang
& Xue 2004). Seven currently
recognized subspecies, classified among five species, occur in the Himalaya and
in the Patkai mountain ranges in northeastern India (the Garo-Khasi-Jaintia
Hills, Patkai-Bum, and the Lushai Hills) (see Table 1 & Image 1). Some of these species and subspecies are very
rare and endemic to these mountain ranges. Among these, S.
silana de Nicéville, 1885, is endemic to
the Eastern Himalaya (Evans 1932; Wynter-Blyth 1957). It is the rarest member of the genus and has
not been seen in the past 90 years (see below). In this paper I report the rediscovery of this species from Sikkim,
Namdapha Tiger Reserve (Arunachal Pradesh) and Nokrek National Park (Meghalaya)
in northeastern India. Symbrenthia silana is legally protected under
Schedule-I of India’s Wildlife (Protection) Act
(Anonymous 1997) and listed in the Red Data Book of Indian Butterflies (Gupta
& Mondal 2005), which makes this rediscovery especially significant.
MATERIALS AND METHODS
To document current populations,
distributions and status of butterflies in the Himalaya, a globally recognized
biodiversity hotspot
(http://www.biodiversityhotspots.org/xp/hotspots/himalaya/Pages/default.aspx),
I have been extensively surveying butterflies throughout the Eastern Himalaya
and northeastern India for the past three years. As part of this long-term butterfly diversity
inventory and monitoring program I conducted preliminary surveys at Namprikdang
(North Sikkim) from 16 to 19 April 2008,and at Pabung Bridge (near Tarku, West Sikkim) on 7-8 November 2009, sighting S. silana at both locations. Since my first sighting of S. silana at Namprikdang three colleagues
have photographed three more specimens at Namprikdang, Namdapha Tiger Reserve
(Arunachal Pradesh) and Nokrek National Park (Meghalaya). Details of all these sightings are provided
below.
While searching the literature for
records of this species I realized that it had not been reported in ca 90
years, hence nothing was known about its habitat or current populations. The sparse information on this species has
also been scattered, often in journals that are not easily accessible to
average lepidopterists and conservationists. Here I present a summary of background information on the species,
discuss its taxonomic status, present its distributional map and compare its
distributional range with ranges of other Indian Symbrenthia species (Image 2). This map was generated from previous
literature and unpublished personal observations.
RESULTS AND DISCUSSION
I. Species description and distinguishing characters:
Taxonomic status and identity of
some of the Indian Symbrenthiaspecies and subspecies have been
debated (see the next section and Table 1). Hence, it is important to define S. silana and to distinguish it from closely similar species. de Nicéville (1885, pp. 117-118) described S. silana as follows:
“Symbrenthia silana, n. sp., Pl. II, Fig. 9, male.
Male: Upperside black, forewing with a very regular streak from
the base to beyond the cell extending slightly below the median but not
touching the subcostal nervure, a subapical irregular streak not quite reaching
to the costa or the outer margin, beyond which is a curved narrow lunular line;
a broad band placed obliquely from the second median nervule to the inner margin. Hindwing with a broad discal band, a submarginal one less than half the
width of the discal band becoming attenuated anteriorly, an obsolete (hardly
traceable) very fine marginal line; all these markings bright ochreous paler in
the middle. Underside
with the markings as above but glossy opaline white, the black ground-colour
replaced by prominent black and yellow tessellations. Hindwing with a discal series of five
imperfect somewhat cone-shaped ocelli of moderate size, the three nearest the
anal angle centred with brilliant metallic blue; three lunules of that colour
at the anal angle. Both wings with the margin black, a
submarginal fine line defined with yellow on both sides.
Female: Larger, the forewing broader, the outer margin evenly
curved. Markings
throughout paler, except the blue ones on the underside of the hindwing, which
are larger and more prominent. The subapical streak on the upperside of the forewing touching the
costa, and a small narrow spot just within it”.
de Nicéville did not specify
collection dates of the specimens, but his description seems to fit the wet
season form, judging by the dry season form subsequently described by Tytler
(1915, p. 511): “The d.s.f. of S. silana only differs from the w.s.f. in being rather smaller and in
having the rufous bands on the upperside if anything slightly broader. On the underside the green of the subterminal cones
on the hindwing is carried on to the forewing, being distinct in interspaces 3
and 4, less so in 2, 5 and 6. On the upperside hindwing there is also sometimes a
distinct fine reddish terminal line”. de Nicéville described the metallic discal cones and tornal
lunules on the hindwing underside as “brilliant metallic blue” whereas Tytler
described them as “green”. This might
seem to stem from real variation in the species: “The type which is in the de
Nicéville collection has the cones and lunules on the underside of the hindwing metallic blue, but it is aberrant in this
respect, the remainder of the specimens in the collection and all my specimens
have it very dark bluish-green” (Tytler 1915). While these markings may be bluish-green, Tytler’s description of
“green” markings seems erroneous. This
is because in all the seven specimens that I have seen, representing specimens
from widely scattered localities and from different seasons, the tornal and
discal markings were some shade of metallic blue.
Symbrenthia silana is most similar to S. niphanda, with which it flies at least in
some areas (Image 2). Due to the close
similarity, S. silana was considered by many authors to
be either a subspecies of S. niphanda or its dry season form (see detailed discussion below). However, the two species may be distinguished
by the following characters (compare in Images 1 & 3): (i) S. niphanda (and also S. brabira and S. hypselis) has on the underside of the
fore-wing “always a black spot base 1 under the spot in the cell near the
base”, which is missing in S. silana (Evans 1932), (ii) both niphanda and silana have metallic submarginal markings
on the hindwing underside, running from tornus to the short tail at v.4 (“the
anal angle” in de Nicéville’s description). However, in S.
silana these markings are either cerulean
or dark metallic blue (or bluish green), very prominently conical in spaces 2
and 3, making their inner margin very wavy. In S. niphanda these markings are much greener and
not conical, with their inner margin much more even. Also, these markings are contiguous from
tornus to v.4 in S.
silana, but sharply and widely broken at
v.2 in S. niphanda, (iii) in S. silana, the paler ochreous bands on the
upperside of the wings are much broader, (iv) the imperfect post-discal ocelli
on the underside hindwing of S. silana are almost half the size of that in S. niphanda, although this seems to be
variable, and (v) the yellow-ringed black spot in space 3 on the forewing
underside, which is part of the post-discal series and is placed centrally in
the black and yellow tessellations in this wing area, is also characteristic. In S. silana this spot is round, whereas in S. niphanda it is laterally compressed (de Nicéville 1885; Tytler 1915; Evans
1932).
A more detailed key to
distinguishing S.
silana from other species is given by
Evans (1932), which will work very well with image 1 in this paper.
II. Taxonomic status of S. silana
Taxonomic assignments of many Symbrenthia species and subspecies have changed
substantially since de Nicéville’s description of S. silana (Moore 1899-1900; Bingham 1905;
Evans 1932; Smith 1989; Huang 1998, 1999, 2000; Fric et al. 2004; Huang &
Xue 2004). Hence, I have summarized in
Table 1 the taxonomic diversity of Indian Symbrenthia. Although the species and subspecies assignments may have
changed, the identification key given by Evans (1932) is still valid (also refer
to Image 1 and notes under Table 1).
The specific status of S. silana had been a matter of debate. de Nicéville himself
later retained it as a distinct species (de Nicéville 1886), as did Moore in
Lepidoptera Indica (Moore 1899-1900). Once the concept of subspecies was applied to butterflies, three
important volumes treated S. silana as a subspecies of S. niphanda (Bingham 1905; Fruhstorfer 1912; Antram 1924). However, based on wing pattern variation
across S. silana and S. niphanda, Tytler felt that S. silana was a good species (Tytler 1915)
and Evans subsequently treated it as one (Evans 1932). Finally, the substantial differences between
male genitalia in S.
silana and S. niphanda firmly established the specific
status of S. silana (Gillham 1956).
Recently, both niphanda and silana were moved into a newly erected
genus, Brensymthia Huang, 2000 (Huang 2000). The creation of this genus should be rejected
because Huang did not give any distinctive characters for the genus, so the
genus was not defined. The species
included under Brensymthiaare not distinctive enough in any
morphological trait to justify a generic status. Moreover, a preliminary
phylogeny of Symbrenthia and allied genera does not support Brensymthia; Symbrenthia being paraphyletic with respect to Brensymthia (Fric et al. 2004). Hence, Brensymthia should be discarded, and silana and niphandashould stand as members of Symbrenthia.
III. Historical records, status and distributional range of S. silana
S. silana has been considered a very rare
species by all previous authors who covered it in any detail (de Nicéville
1885, 1886; Elwes 1888; Tytler 1915; Evans 1932; Wynter-Blyth 1957); and
rightly so, since less than 40 specimens have ever been collected. There are 11 specimens, all collected from
“Sikkim-Buxa”, in the National Zoological Collection of Zoological Survey of
India, Kolkata (ZSI), and one specimen in the entomological collection at the
Forest Research Institute, Dehra Dun (Gupta & Mondal 2005). de Nicéville’s
collection at the Indian Museum in Kolkata, where he was a curator, is now part
of the ZSI. It is likely that de
Nicéville’s species description was based on these very 11 specimens since his
specimens were collected by the museum-appointed collector Moti Ram from “Buxa,
Bhutan”, and by Otto Möller in “Sikkim” (de Nicéville 1885). Exact localities of Möller’s Sikkim specimens
are unknown, although they were collected at ca 600m aslin May (Elwes 1888). Moti Ram’s
specimens from “Buxa, Bhutan” could either be from the present Buxa Tiger
Reserve in northern West Bengal, bordering Bhutan to the north and Sikkim to
the north-west, or they could be from the Bhutan part of this forest (I am
unable to determine how the boundary between India and Bhutan has changed since
de Nicéville’s species description, and whether Moti Ram’s specimens are likely
to have come from West Bengal Buxa or from Bhutan, as originally
reported). The 12 specimens mentioned
above are the only ones known in Indian research collections. There are no specimens in the Madras
Government Museum (Satyamurti 1966). A
recent exhaustive book on Sikkim butterflies listed three Symbrenthia species: S. lilaea khasiana, S. hypselis cotanda, and S.
n. niphanda, but did not even mention S. silana (Haribal 1992). Haribal’s color plates were based on
specimens deposited in the Bombay Natural History Society’s collection, so
presumably there are no specimens there.
The second set of S. silana specimens were collected in
Nagaland and Manipur, and were deposited in the British Natural History Museum
(now Natural History Museum), London (Tytler 1915). Tytler collected seven males and two females
of the wet season form from July-October at ca 1,800m aslat Kirbari, Naga Hills. Kirbari is near
Phesima, lying below Mt. Paona (25030’N & 93039’E),
District Kohima, Nagaland. Tytler also
collected 13 males of the dry season form from Sebong, eastern Manipur Hills,
and “on the Irang River, Western Manipur Hills”. The exact locality of his “Irang River”
specimens cannot be determined. Sebong (=Sibong; approximately, 24020’N
& 94016’E) is
situated in Chandel District, Manipur, on the Myanmar-India border.
As far as I know, Tytler’s report
of S. silana was the last record of the
species. All subsequent mention of the
species has been a repetition of information given by de Nicéville (1885) and
Tytler (1915). Gillham (1956) reported
new information – genitalic differences between S. silana and S. niphanda – although the specimen he
examined was previously collected at “Sivoke, Sikkim”, and deposited in the
U.S. National Collection (the Smithsonian Institution National Museum of
Natural History) (Gillham 1956). Sevoke
(=Sivoke), near Siliguri, was previously part of Sikkim but is now in northern
West Bengal. Gilham did not specify the
original collector and collection date.
Apart from these specimens reported
in literature, some more specimens may be found in various museums if their
collections are carefully examined. For
example, I found a single S. silana specimen, incorrectly labeled S. niphanda, in the butterfly collections at Harvard University’s Museum of
Comparative Zoology (illustrated in Fig. 1). Currently this specimen has four labels on it: “S. NIPHANDA. M. Sikkim”,
“3736”, “Sikkim”, and “AG Weeks Collection”. The original collector and collection date of this specimen are unknown.
Thus, S. silana has rarely been collected, is
considered very rare, and its distributional range is known only from four
specific localities (Sevoke, Buxa, Kirbari and Sibong) and two general areas
(“Sikkim”, and “Irang River, western Manipur Hills”). These localities are scattered over the
entire span of the Eastern Himalaya (Image 2), although the known distribution
is very patchy. The species had not been
reported from Arunachal Pradesh, upper Assam and rest of Bhutan, which together
cover most of the E. Himalaya, where surveys are needed. The species also has the narrowest range
among all its Indian congeners.
IV. Rediscovery of S. silana:
(A) Recent sightings with
locality and habitat information: S. silana was rediscovered from Namprikdang
in North Sikkim, approximately 90 years after Tytler’s collection of the
species. The first sighting was most
likely a male that I photographed mud-puddling at noon on 16 April 2008 outside
the Namprikdang Forest Rest House (Image 3a). The second sighting was an unsexed individual photographed nearby by
Ullasa Kodandaramaiah on 19 April 2008 (Image 3b). Namprikdang (27031.213’N & 88031.905’E;
elevation ca 1,000m) is near the village of Mangan in North Sikkim. It is a
mosaic of sparse, disturbed mixed deciduous and semi-evergreen forests and
small settlements of the native Lepcha people (Image 5). The trees are 15-20 m tall, and Pandanus plants are common.
Subsequently, Arjan Basuroy and
Rudraprasad Das photographed two specimens in Namdapha Tiger Reserve in eastern
Arunachal Pradesh (27037.48’N & 96005.57’E, elevation
ca 550m asl) (Images 3e & 3f). The first specimen was mud-puddling at 1100hr
on 17 March 2009 in a wide, open stream flowing out of the subtropical
evergreen forest at Chidiapung. The
second specimen was also mud-puddling in a similar stream at 1042hr on 25 March
2009, 5km from the Deban Rest House. These
two dry season forms were differently marked than other specimens recently
sighted, which were all wet season forms. They were much more ochreous on the underside, with dark ochreous cones
masking portions of the metallic blue tornal cones in space 1 and 2 around v.2. Because of these dark ochreous cones the
tornal blue coloration seemed interrupted. In the wet season forms the ochreous markings and cones were greatly
reduced, thus the blue tornal cones seemed uninterrupted (compare in Image
3). These dry season forms, however, did
not have blue scaling on the underside extended to the forewing, as described
by Tytler (1915; see above).
I made the fifth sighting of a maleS. silana mud-puddling at Pabung Bridge in
western Sikkim at 1140hr on 8 November 2009 (27014.296’N & 88026.948’E;
elevation ca 1,000m asl) (Images 3c & 3d). Pabung Bridge has a small patch of dense remnant subtropical evergreen
forest, where the trees are 15-20 m tall. A small perennial stream cuts through the narrow, steep valley.
The last sighting was by Kedar
Tokekar, who photographed a worn specimen mud-puddling along a densely wooded
stream through an evergreen forest (Images 3g & 3h). This sighting was made at 1103hr. on 9
November 2009 in Nokrek National Park, Garo Hills, Meghalaya (25028.30’N
& 90018.25’E; elevation 1,074m).
(B) Revised distributional
range, populations and status of S. silana: This
report adds the states of Arunachal Pradesh (Namdapha Tiger Reserve) and
Meghalaya (Nokrek National park) to the previously known distributional range
of S. silana. The Nokrek record is remarkable because the species had not been
previously reported from the Garo Hills. Due to border realignment, the old Sevoke record now adds this species
to the butterfly fauna of West Bengal. Thus, from the old records and the newly reported sightings here, S. silana is now known to occur all over the
E. Himalaya from Sikkim (Namprikdang and Pabung Bridge) and West Bengal (Sevoke
and Buxa) through Bhutan (? Buxa) to Arunachal Pradesh
(Namdapha); and in the Patkai Range covering the hills of Manipur and Nagaland,
and the Garo Hills in Meghalaya. The species has been reported from low-lying and mid-elevation
(600-1,800 m) evergreen forests, but the full range of its habitat is poorly
understood.
The recent sightings show that
Sikkim, Namdapha and Nokrek presently support populations of S. silana. Of these, Sikkim populations may
be most vulnerable to local extinction. The Sikkim Government is building numerous large dams, including one
near Namprikdang, to feed India’s growing hunger for electricity. These dams will most likely destroy or
disturb habitat of S.
silana and other federally protected
species. Both Namprikdang and Pabung
Bridge are outside any major protected areas, so the long-term persistence of
forests and S. silana populations there is
doubtful. There has also been widespread
deforestation in the states of Nagaland and Manipur. Most of the forests near Siliguri and other
areas in northern West Bengal have either been cut or degraded and are
increasingly under greater human pressure. Hence, the status of populations in
these areas, if they can be located, is also uncertain.
Under this scenario, only the
populations in Namdapha Tiger Reserve and Nokrek National Park are secure,
since both are in protected areas administered by the Indian central
government. Buxa, if it still has any S. silana, would also be secure since the
forests there are protected under the Buxa Tiger Reserve by the Indian
government. Buxa is flanked by Bhutanese forests to the north, and in the east,
by the Manas Tiger Reserve and its reserve forests in Assam. The priority now should be to locate
populations of this very rare and legally protected species at the specific
localities mentioned in older literature, and in new places where it may be
found.
(C) Description of habits: My observations on the habits of S. silana are limited, but I report them
here since little else is known. All
except Ullasa Kodandaramaiah’s sighting were of mud-puddling individuals (Image
3). The specimens held wings open once in a while, slowly moving them up and
down as they turned around their mud-puddling spots. The individuals were somewhat wary and, if
approached, would fly for several meters near the ground. Their flight was
similar to that of S.
lilaea and S. hypselis: strong, with rapid wing beats,
interspersed with short glides. However,
the butterflies settled frequently, often on low vegetation. If disturbed while mud-puddling, the butterflies
returned to the same or nearby mud-puddling spots shortly afterward. The butterflies had the tendency to perch
with wings closed when they landed on vegetation, but rested with wings spread
flat soon afterwards, until they moved on again.
The specimen spotted at Pabung
Bridge was mud-puddling not only on wet soil but also on very dry stones at the
edge of the stream. In the latter case,
it would bend its abdomen and deposit a drop of water on the rock, which
apparently quickly dissolved minerals. The butterfly would then suck back the drop of water with its proboscis,
and repeat the process several times (Image 4). Similar behavior is also common in many hesperiids and lycaenids.
V. Legal protection and conservation of S. silana
S. silana has been included in Schedule-I of
India’s Wildlife (Protection) Act, henceforth WPA (Anonymous 1997). This
listing ties it with such iconic species as the tiger, snow leopard and great
pied hornbill, which receive the highest level of legal protection in India
(Anonymous 1997). The listing was made
in 1972, before a formal framework to list species under various WPA Schedules
was available (such as that provided by the International Union for
Conservation of Nature and Natural Resources (IUCN) Red List Categories and
Criteria (IUCN 2001)). When the listings were initially made, apparently the
sole, remarkably subjective criterion used to list butterfly species under
Schedule-I was that the species had been listed as “very rare” in Evans’s 1932
monograph on Indian butterflies (Gupta & Mondal 2005, p. 19). Gupta & Mondal (2005) later rationalized
the inclusion of S.
silana in the WPA Schedule-I based on its
narrow endemism and rarity. They classified its status as “Vulnerable (Vu A1c, B1 2bc)” following IUCN’s Red List Categories and
Criteria (Gupta & Mondal 2005). This
classification translates as: the fear of a high risk of extinction of the
species in the wild from: (a) an estimated population size reduction of
≥50% over the last 10 years from a decline in area of occupancy, extent
of occurrence and/or quality of habitat (“Vu A1c”), and (b) an estimated geographic
range of ≤20,000 km2 with the habitat/populations being
severely fragmented, where the populations are continuing to decline at a rapid
rate (“B1 2bc”) (IUCN 2001; Gupta & Mondal 2005). This classification is probably useful but
there is no evidence that the habitat and populations of S. silana have either declined or been
fragmented at such an alarming rate during any time in history. In the absence of any sightings or detailed
surveys of the area for several decades, no such information had been available
on this species.
I hope that the recent sightings
and the information provided above will spur interest in the ecology and
conservation of S.
silana. The first step would be to intensively survey its populations, delineate
its current distribution and determine its status in various areas. Generating information on seasonal population
dynamics, the early stages and host plant use would also be very
important. This information will be
critical in protecting this species. Based on my recent sightings, at the closing of the Forest Centenary on
12 December 2009, Department of Forest, Environment and Wildlife Management,
Government of Sikkim, presented S. silana to the state of Sikkim as its “centennial butterfly”. I hope that the beauty and rarity of this
species will generate further enthusiasm within the Sikkim and West Bengal
State Forest Departments. Such
enthusiasm may be capitalized upon to facilitate creation of butterfly
sanctuaries in the currently unprotected forest fragments at Pabung Bridge,
Namprikdang and near Sevoke. Previous
observations have shown that butterfly populations can persist even in very
small forest fragments for decades (Larsen 2008; Larsen et al. 2009). Hence, the creation of such butterfly
sanctuaries in remnant forests across the Eastern Himalaya may help to connect
and protect populations of S. silana and other WPA-scheduled butterfly species. This will also conserve
the overall butterfly diversity of this important biodiversity hotspot.
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