Journal of
Threatened Taxa | www.threatenedtaxa.org | 26 May 2018 | 10(6):
11775–11779
A new record of the lesser-known butterfly Small Woodbrown
Lethe nicetella de Nic思ille, 1887 (Lepidoptera:
Nymphalidae: Satyrinae)
from Khangchendzonga National Park, Sikkim, India
Sailendra Dewan 1,
Bhoj Kumar Acharya 2 & Sudeep Ghatani 3
1,2,3 Department of Zoology, Sikkim University, Tadong, Gangtok, Sikkim 737102,
India
1 dewansailendra1992@gmail.com, 2 bkacharya@cus.ac.in
(corresponding author), 3 sghatani@cus.ac.in
Abstract: This study reports the recent sighting
of Small Woodbrown Lethe nicetella
from Khangchendzonga National Park in West Sikkim
District, India. It was originally
described by de Nic思ille (1887) based on the
collection of males and one female by Otto M嗟ler
from Sikkim but the exact type locality was unknown. We also reviewed various historical and
contemporary reports on the description and distribution of this species. We did not find any report of collection
or sighting of the species from India after Elwes
& M嗟ler (1888). The occurrence of this species in Sikkim
is mentioned in Haribal (1992) but it is not clear
whether the report is based on sightings or historical records because sighting
location is not given, indicating its description based on museum specimens.
Hence, we conclude that the Small Woodbrown L. nicetella was sighted after a gap of around 120
years. Further, we have provided
the first photographic records of a live individual of this species from
India. Our finding indicates a possibility
of existence of many cryptic taxa that should be explored using morphological
and molecular approaches.
Keywords: Butterflies, Lethe nicetella, Sikkim, Small Woodbrown.
doi: http://doi.org/10.11609/jott.3987.10.6.11775-11779 | ZooBank:
urn:lsid:zoobank.org:pub:AF06A883-FD20-4383-A6F0-D28B3963E1E6
Editor: Sanjay Sondhi Titli
Trust, Dehradun, India. Date
of publication: 26 May 2018 (online & print)
Manuscript details: Ms # 3987 |
Received 30 December 2017 | Final received 08 February 2018 | Finally accepted
02 May 2018
Citation: Dewan. S., B.K. Acharya
& S. Ghatani (2018). A new record of the lesser-known
butterfly Small Woodbrown Lethe nicetella de Nic思ille, 1887
(Lepidoptera: Nymphalidae: Satyrinae)
from Khangchendzonga National Park, Sikkim, India. Journal of Threatened
Taxa 10(6): 11775–11779; http://doi.org/10.11609/jott.3987.10.6.11775-11779
Copyright: ゥ Dewan. et
al. 2018. 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: This paper is a part of the project メDistribution pattern and conservation of butterflies along the elevational gradient in Rangeet Valley, Sikkim, Eastern Himalayaユユ funded by The Rufford Foundation through Rufford Small Grants, UK (Grant ID:20758-1). SD was supported with non-NET
fellowship of University Grants Commission, New Delhi provided through Sikkim University.
Competing interests: The authors declare no competing interests.
Acknowledgements:
We thank Sikkim University for providing facilities to
undertake this research. We would like to thank Dr. Peter Smetacek
and Mr. Monsoon Jyoti Gogoi
for helping us with identification of Lethe nicetella
and providing valuable historical notes on this species. We thank Dr. Basundhara Chettri for valuable
suggestion on taxonomic approaches. We are grateful to the Research Evaluation
and Monitoring Cell (REMC) of the Department of Forest, Environment & Wildlife
Management, Government of Sikkim for providing us with
permit to study butterflies in Sikkim. We would like to thank Mr. Nawangla Bhutia along with other
members of Butterfly and Moths of Sikkim, Nature Conservation Society (BAMOS)
for their continued support in our field studies.
Lethe Hubner [1819], is a
butterfly genus under the subfamily Satyrinae of the
family Nymphalidae. The genus is distributed from Borneo
through the Sunda Islands, Japan, Siberia, Himalaya
and peninsular India (Mani 1986).
Morphologically, the upperpart of these
butterflies are brown with apical spots on the forewing and spots or ocelli on the hindwing. They also
bear distinctive ocelli on the under parts of the
wings. The habitat of most of the
species of this genus is bamboo forest or grassy patches in the forest.
Sikkim
is a small land locked Himalayan state in India covering an area of
7,096km². It lies in western
extremities of the eastern Himalaya, a part of one among the 36
biodiversity hotspots of the world (CEPF 2017). Due to its steep mountainous terrain,
Sikkim experiences rapid changes in climatic condition from sub-tropical type
in low elevation to alpine condition in high elevation. The synergetic effect of elevation,
climate and historical factors (pre-historic tectonic movements and paleoclimate) has made it one of the most biologically
diverse regions in the world, despite its small area (Ali 1962). Butterflies in Sikkim are represented by
689 species, and genera such as Lethe appear to display high diversity (Haribal 1992).
Eminent
naturalists extensively documented butterflies of Sikkim in the 19th
century. Among them were the noted
entomologists de Nic思ille (1881, 1882, 1883, 1885,
1894) and Elwes (1882, 1887) but most of this
literature refers to taxonomy and listing of species. Haribal et al.
(1988) presented a checklist of 103 species of butterflies along with their
sighting locations in Sikkim. Haribal (1992) remains the most exhaustive publication made
so far on the butterflies of Sikkim. With a gap of almost two decades,
systematic studies on butterflies in the region have increased in recent years
(Acharya & Vijayan
2011, 2015; Chettri 2015). Species protected under Indian Wildlife
(Protection) Act 1972, such as Symbrenthia silana (Kunte, 2010), Lethe
margaritae and Neptis
nycteus (Rai et al.,
2012) have recently been rediscovered in the state after almost 100 years. All these studies have indicated the
probability of occurrence of many species that awaits rediscovery or possibly
even new species discovery.
Here,
we report the recent sighting of Small Woodbrown Lethe
nicetella from Bakhim
in West Sikkim District, Sikkim, India. The species is protected under Schedule
II of Indian Wildlife (Protection) Act 1972 (Anonymous 1997). We also reviewed various historical and
contemporary reports on description and distribution of this species. Since very less information is available
on this species (and genus Lethe as a whole), our findings add to the
existing information on Lepidoptera of the Indian sub-continent in general and
Eastern Himalayan region in particular.
Distribution, habitat and status based on
literature
Lethe nicetella is one among diverse group of species under Lethe genus of
subfamily Satyrinae. L. nicetella
was originally described by de Nic思ille (1887)
based on the collection of males and one female by Otto M嗟ler
from Sikkim but the exact type locality is unknown. Based on the museum specimen housed in
the Natural History Museum, London, Talbot (1947) reported the occurrence of
the butterfly in Gangtok and Karponang
in Sikkim (1,524–2,740 m elevation).
The other notable mention of this species is by Elwes
& M嗟ler (1888). The authors recorded this
species along the Goompahar and the flanks of Tonglo during July and August. メGoompaharモ
referred to here is now known as メGhoomモ and メTongloモ as Tonglu, both lies in
Darjeeling District, West Bengal, India.
Darjeeling was a part of the then Kingdom of Sikkim, but later managed
under the British Empire and now a part of West Bengal State in India (Subba 1992).
Hence, based on Elwesユs observation (Elwes & M嗟ler 1888),
Darjeeling, West Bengal, should be included in distribution range of the
species in the upcoming literatures.
Bailey (1951) reports the occurrence of the species in Chandagiri (1,820m) and Godavari (1,520m) in Nepal, which
could be considered as the western most extent of the species. The species has also been known to occur
in Bhutan (Singh & Chib 2015). Several authors have mentioned the
occurrence of this species from India but it is not clear whether the authors
collected the specimens or referred to the museum specimens (Table 1).
The
male butterfly has been reported to be more common than the female (de Nic思ille 1887; Elwes & M嗟ler 1888); however, this butterfly has been considered
to be rare (Evans 1927; Tablot 1947; Haribal 1992; Kehimkar 2008).
Table 1. Details of historical records
of Lethe nicetella from India
Scientific Name |
Locality and elevation |
References |
Lethe nicetella |
Sikkim (based on Otto M嗟lerユs collection) |
de Nic思ille
(1887) |
Lethe nicetella |
Collected from Ghoom
and Tonglu (now in West Bengal), 2,134–2,744
m |
Elwes & M嗟ler
(1888) |
Sinchula nicetella |
Sikkim (Based on
de Nic思ille 1887) |
Moore (1892) |
Lethe nicetella |
Sikkim, 2,134m |
Bingham (1905) |
Lethe nicetella |
Sikkim, 2,134m |
Antram (1924) |
Lethe nicetella |
Mentioned about museum specimen
collected from Gangtok and Karponang
in Sikkim, 1,524–2,744 m |
Tablot (1947) |
Lethe nicetella |
Sikkim |
Wynter-Blyth (1957) |
Lethe nicetella |
Sikkim |
Haribal (1992) |
Lethe nicetella |
Sikkim, 1,800–2,800 m |
Kehimkar (2008) |
Description of the species
Lethe nicetella is one of the smallest species in the Lethe genus with a wingspan
of 45–50 mm. Moore (1892)
referred to this species as Sinchula nicetella but successive authors have followed the
original name, i.e., Lethe nicetella.
The key
morphological features of this species that distinguishes it from other similar
species (Lethe sidonis and Lethe nicetas) are given in Table 2.
Recent sightings
We
sighted Lethe nicetella in Bakhim
(27.910N & 88.190E) at approximately 2,700m elevation
in West District of Sikkim, India (Image 1). Bakhim is one
of the resting places along the Yuksom-Dzongri trek,
a famous trail for expedition to Mt. Khangchendzonga. The area falls under Khangchendzonga
National Park (KNP), a recently designated UNESCO World Heritage site. The mean annual temperature of Bakhim is around 11.58。 C, while mean annual precipitation
is 1,827mm. Bakhim
is characterized by temperate mixed broadleaved forest. Trees such as Castanopsis sp., Quercus
sp. and Rhododendron arboreum are common
in the area (Image 2). Various
species belonging to genus Magnolia, Michelia,
Ilex, Cinnamomum, Betula
can also be found here. Secondary growth consists of Debregeasia
sp., Utrica sp., Viburnum sp.,
Osbeckia sp., etc.
Six
individuals of Lethe nicetella were seen at
around 11:00hr on a sunny morning on 18 June 2017. The species was initially mistaken as
Common Woodbrown Lethe sidonis,
a closely resembling species; however, the absence of ocelli
on its forewing provided a clue of it being a different species. We quickly photographed the species
(both underwing and upperwing;
Image 3) and matched the characteristic features of the photographed individual
to that of the description in literature (de Nic思ille
1887; Evans 1927; Haribal 1992; Kehimkar
2008). On careful examination and
with the help of experts we identified the species as Lethe nicetella.
The butterflies were feeding on faeces of cattle and horses and some
individuals were basking exposing their golden-brown upperwing. On being disturbed, the butterflies flew
short distances and kept close to the ground.
We did
not find any reports of collection or sightings of the species from India after
Elwes & M嗟ler
(1888). While Haribal
(1992) mentioned the occurrence in Sikkim but it is not clear whether the
report is based on sightings or historical records. The author also mentions that out of 689
species listed, only 250 species were primarily sighted, and location of
sightings has been provided for all of these species. Since the locality of occurrence of Lethe
nicetella is not mentioned in Haribal
(1992), we believe that the description was based on museum specimens. Hence, we conclude that this is the
first sight record from India after a gap of around 120 years. Further, we have provided the first photographic
records of the occurrence of this species in India. Photographic record of this species is
also not available in exhaustive online sources such as
http://www.ifoundbutterflies (Kunte et al. 2018).
Based
on our field study, the species is not very rare in its distribution range,
more specifically in the area of recent sightings. Because of high similarity, researchers
and naturalists could easily confuse Lethe nicetella
with Lethe sidonis. Hence, the occurrence and sightings of
this species may have gone unnoticed.
Table 2. Key morphological differences
to distinguish Lethe nicetella from Lethe sidonis and Lethe nicetas
(de Nic思ille 1887; Elwes
& M嗟ler 1888; Bingham 1905; Evans 1927; Wynter-Blyth 1957)
Features |
Common Woodbrown
Lethe sidonis |
Yellow Woodbrown
Lethe nicetas |
Small Woodbrown
Lethe nicetella |
Wingspan |
45–60 mm |
48–55 mm |
45–50 mm |
Upper part |
Deep bronzy brown |
Golden brown |
Golden to reddish-brown |
Underside sub-apical ocelli
in forewing |
Present |
Present |
Absent |
Underpart ocelli in the
hindwing |
Subequal with ocelli
in 3 and 4 blurred |
All ocelli
clear |
Similar to Lethe sidonis |
Conclusion
The
rediscovery of Lethe nicetella after a gap of
120 years in Sikkim has indicated the occurrence of its habitat and host plants
in the region. No literatures,
however, on host plants or ecology of this species are available. We also presume that more such species
occur in the region and need further exploration. There is a possibility of existence of
many cryptic taxa that should be explored using morphological and molecular
approach. The conservation focus is
more biased towards large and charismatic species but butterflies are also a
significant component of the forest ecosystem. Hence, conservation attention is
necessary for protection and long-term survival of underrepresented taxa such
as butterflies.
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