Journal of Threatened Taxa | www.threatenedtaxa.org | 26 February 2019 | 11(3): 13320–13333

Butterflies of the myristica swamp forests of Shendurney Wildlife Sanctuary in the southern Western Ghats, Kerala, India

Prabhakaran Chandrika Sujitha ¹, Gopal Prasad ²  & Kalesh Sadasivan ³

1,2 Department of Zoology, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala 695581, India.

3 Travancore Nature History Society, MBRRA 65, Jyothis, Mathrubhumi Road, Vanchiyoor, Thiruvananthapuram,

Kerala 695035, India.

1 sujeespc@gmail.com, 2 probios1@gmail.com, 3 kaleshs2002in@gmail.com (corresponding author)

Abstract: Myristica swamps are unique freshwater swamp forests characterised by predominance of tree species of the Myristicaceae family.  There have been few published works on the flora and fauna of myristica swamps but studies on butterflies have been scanty. This work was done in the myristica swamps of Kattilapara in Shendurney Wildlife Sanctuary, Kollam district, Kerala, located in the northern aspect of the Agasthyamalai Hills of the southern Western Ghats. Data on the butterflies were collected over a period of two years supplemented with data from previous visits using Transect method. Butterflies were identified based on field photographs and relevant literature. We recorded 206 species of butterflies belonging to 6 families from the myristica swamps. This included 17 species of Papilionidae, 20 species of Pieridae, 65 species of Nymphalidae, 56 species of Lycaenidae, two species of Riodinidae and 46 species of Hesperiidae.Of the total, 19 species of butterflies were Western Ghat endemics. A checklist of butterflies of the myristica swamp, larval hostplants, status with respect to IUCN criteria, endemicity, and classification as per Indian Wildlife Protection Act (WPA) of 1972 are also provided. Eighty-two species of plants were listed as butterfly larval hosts in the myristica swamp ecosystem, with 27 species being new host records for Western Ghats. None of the butterflies recorded were using plants of Myristicaceae family as larval hosts. A simple index—the percentage occurrence—is proposed to delineate the habitat affinity of species.

Keywords: Agasthyamalai Hills, larval host plants, habitat affinity.

Introduction

Myristica swamps are tropical swamp forests first reported from Kulathupuzha Reserve Forests and adjoining regions of Anchal, Thenmalai and Shendurney Wildlife Sanctuary (WS) in Kollam and Thiruvananthapuram districts of Kerala (Krishnamoorthy 1960).  Besides Kerala, they are also known to occur in Karnataka and Goa (Joyce et al. 2014).  Myristica swamp forests are floristically lowland (180–200 m) edaphic variants of evergreen forests with canopy at 30–40 m, with pure patches of Myristicaceae trees in a freshwater swamp amidst tropical evergreen patches (Subramanian 1995).  These are highly fragmented ecosystems with restricted distribution (Rodgers & Panwar 1988a,b).  The dominance of the trees of Myristicaceae family in the swamps gives them their common name (Roby et al. 2014).  The myristica swamps are classified as forest type 4c/FS1, under Champion & Seth (1968).

There have been a few studies on the flora and fauna of myristica swamps.  Notable works on their basic ecological aspects are by Nair et al. (2007) from Kerala and Ramabhat & Kaveriappa (2009) from Uttara Kannada.  Floristic works on this unique ecosystem can be seen in Varghese & Menon (1999), Roby et al. (2007, 2014), Subash et al. (2008), Sreejith et al. (2016) and Joyce et al. (2014).  Floristic studies by Roby et al. (2014) had listed 79 species of trees, 93 species of herbs and shrubs, and 49 species of climbers in this ecosystem of which 49 are endemic and 18 are IUCN Red List species.  There are only a few studies available on faunal diversity of myristica swamps.  The insect diversity in these swamps were studied by Sinu & Sharma (2013); spiders by Joyce et al. (2007a); reptiles by Joyce (2007b,c).  The general insect diversity of Shendurney WS was covered by Mathew et al. (2004) and the butterflies list can be seen in Anonymous (2012).

Butterfly fauna of myristica swamps were largely unknown and only a very few studies are available in this regard.  Ali et al. (2008) worked on the myristica swamps of Uttara Kannada and recorded 57 species of butterflies in three families Papilionidae, Pieridae, and Nymphalidae.  Joyce et al. (2015) identified 72 species in five families and 57 genera during the work in Anchal, Kulathupuzha, and Shendurney over three years.  Thus, studies on lepidopteran fauna of myristica swamps have been very scanty.  The present study documents of butterflies of myristica swamps of Shendurney WS (8.858⁰N & 77.210⁰E) in the northern aspect of the Agasthyamalai Hills of the southern Western Ghats in Kerala.

Materials and Methods

Study Area

The myristica swamps at Mankuthu and Onnam-Mile in Kattilapara region of Shendurney WS were studied (Fig. 1).  The Mankuthu myristica swamp lies about 1.5km behind the Kattilapara base camp and is at the edge of the sanctuary, while the Onnam-Mile myristica swamp lies about 2.5km inside the sanctuary on the right of the road leading to Kallar.  Anthropogenic factors do not seem to play any significant influence on the swamp ecosystem as both are inside the protected area of the sanctuary.

Two myristica swamps were studied in the Kattilapara region of the Shendurney WS (Image 1).  Data on butterflies for POc scores (see below) were collected over a period of two years for every two weeks from May 2016–May 2018 using transect method.  Permanent line transects covering 500m over 30 minutes were taken in the morning (8–9 am) and evening (3–4 pm) to study the butterfly diversity of the myristica swamp and the adjoining evergreen forest patch.  The transects were such that it covered 500m of swamp and 500m of the adjoining evergreen forests.  This intensive two-year work was supplemented with additional data from previous visits to this area using the same 500m/30 min transect method, taken once a month, spanning over the last 10 years (2008–2018), for butterfly diversity and hostplant records.  For delineating species that are myristica swamp dependent, we compared the butterfly occurrences in the myristica transect with another 500m control transect laid in the adjacent evergreen forest.  Butterflies that were recorded in more than 50% of transects in myristica swamps in comparison to the adjacent control transect was taken as myristica swamp species (MSS).  This included species with 50–75 % occurrence in the swamp, treated as myristica swamp associates (MSA), and those with occurrence of more than or equal to 75% of transects classified as myristica swamp dependents (MSD).

 MSS = MSA+MSD

Those species which were seen <50% were classified as stragglers and were present more outside the swamp than in it.  This treatment was supplemented with host plant and early stage data for these butterflies from our observations.  Species with their known hostplant distribution restricted to myristica swamps were also considered as myristica swamp dependents (MSD).

To ascertain the habitat affinity and distribution among habitats, we propose here a very simple index — the percentage of occurrence (POc).  The total number of individuals of a species is taken and the proportion of them seen in the particular habitat is calculated.  For example, in the case of the swamp, we calculated the POc score as per the following equation:

                                                                                      n (Swamp) x100

Percentage of Occurrence (POc) in Swamp = –––––––––––––––––––––

                                                                               n (Swamp) + n (Evergreen)

POc(Evergreen) = 100-POc(Swamp)

Here n was the absolute number of individuals of a particular species seen in a transect (myristica swamp or evergreen forest) added over the study period.

Butterflies were identified based on field photographs and relevant literature.  Oviposition alone was not taken as primary criteria of hostplant confirmation because of the well-known oviposition mistakes.  Oviposition on an already known plant species being utilized elsewhere, or presence of more than one instar of the larval stages of a butterfly on the plant on which an egg is laid or successful field observation of the larvae surviving to adulthood on the particular plant was taken into consideration to establish a plant as the larval hostplant.  Larval identification follows Bell (1909–1927) and Kunte et al. (2018).  Identification of adult butterflies are based on Evans (1932) and taxonomy follows Kunte et al. (2018).  Larval host plants used by butterflies in the myristica swamps were photographed.  Floras referred for identification of the larval hostplants are Ramarao (1914), Gamble (1967), Subramanian (1995), Blatter & Millard (1997), Sivarajan & Mathew (1997) , Seethalakshmi & Kumar (1998), Renuka (2000), Ravi & Mohanan (2004) and Nayar et al. (2006).  Host plant utilization was checked against Sevastopulo (1973), Kunte (2000, 2006), Robinson et al. (2001), Kalesh & Prakash (2007, 2015), and Nitin et al. (2018).

Results and Discussion

Vegetation

The vegetation of the swamps are evergreen species with a majority of the trees being from Myristicaceae.  The swamps had a predominance of myristica trees Gymnacranthera farquhariana J.Hk. & Thoms., and Myristica fatua var. magnifica (Bedd.) Sinclair from Myristicaceae family.  Other trees observed were Syzygium travancoricum Gamble, Vateria indica L., Hopea parviflora Bedd., Lophopetalum wightianum Arn., Holigarna arnottiana J.Hk., occurring as dominant species.  Pandanus thwaitesii Martelli, Phrynium pubinerve Bume, Indianthus virgatus (Roxb.) Suksathan & Borchs., and Carex sp. constituted the undergrowth.  The ground vegetation was mainly of Lagenandra ovata (L.).  Climbers were also seen in the swamps especially Parsonisia spiralis Wall. ex G.Don and Lianas included Kunstleria keralensis Mohanan & Nair, Chilocarpus denudatus Blume, Gnetum edule (Willd.) Blume, and Ventilago bombaiensis Dals.  There were also climbing ferns and Calamus represented by Calamus thwaitesii Becc., Calamus hookerianus Becc., and C. travancorius Bedd. ex Becc., especially in the ecotone with adjacent lowland evergreen forests.  The swamp edges had a good undergrowth of plants from Rutaceae, Aristolocaceae, Fabaceae and Poaceae.

Butterfly fauna

In the Myrstica swamp forests, 206 species of butterflies were recorded over a study period of two years (Appendix I).  Of these, seven species were MSD with POc value more than or equal to 75, 151 species were MSS with POc >50 and the rest 48 were stragglers (POc <50).

Myristica swamp Dependents (MSD)

Idea malabarica (Moore, 1877) is a typical MSD species with a POc value of 87.5 (Table 1).  The regionally preferred host plant is Parsonisia spiralis Wall. ex G.Don (Apocynaceae), and this plant is mostly restricted to the myristica swamps of the region, which explains its high POc value 87.5.  For Papilio dravidarum Wood-Mason, 1880, Clausena heptaphylla (Roxb.) Wight & Arn. and Glycosmis pentaphylla (Retz.) DC. (Rutaceae) are the known larval hostplants seen in the swamp.  The species was found to have a POc value of 81.81.  For Neopithecops zalmora dharma (Moore, [1881]), Glycosmis mauritiana (Lam.) Tanaka, and Glycosmis pentaphylla (Retz.) DC. (Rutaceae) are the known larval hosts seen in the undergrowth of the swamp edges.  This small lycaenid had a POc of 80.95.  Arhopala alea (Hewitson, 1862) had three known host species Terminalia paniculata Roth, Hopea sp. (Dipterocarpaceae) and Syzygium salicifolium (Wight) J.Graham (Myrtaceae).  This is a rare butterfly in the region with POc value of 76.92.  Males were seen mudpuddling on the sandy edges of swamps in drier winter months.  Pachliopta pandiyana (Moore, 1881) is a monophagus species endemic to Western Ghats that feeds on Thottea siliquosa (Lam.) Ding Hou (Aristolochiaceae).  This host plant was an ecotone species seen at the edges of the swamps.  The POc value was 75.47.  Arhopala bazaloides bazaloides (Hewitson, 1878) has Hopea ponga (Dennst.) Mabb.(Dipterocarpaceae) as the known larval hostplant.  The butterfly was a rare one with POc 75.  Arhopala abseus indicus Riley, 1923 was a rare butterfly of the region with high POc of 75 with Shorea robusta C.F. Gaertn. (Dipterocarpaceae) was the only recorded hostplant in literature.  We report here a species of Hopea as its new host plant.  This Hopea sp. was generally seen on the fringes of the myristica swamps of the region.

Among the MSD species Idea malabarica (Moore, 1877), Papilio dravidarum Wood-Mason, 1880, Pachliopta pandiyana (Moore, 1881) and Arhopala alea (Hewitson, 1862) are endemic to the Western Ghats (Larsen 1987).  Two species of the MSD are on the IUCN Red Data List, viz., Arhopala bazaloides bazaloides (Hewitson, 1878) under Least Concern category and Idea malabarica (Moore, 1877) under the Near Threatened category (IUCN 2018).  One species, Arhopala bazaloides bazaloides (Hewitson, 1878) comes under Schedule II of the Indian Wildlife (Protection) Act, 1972.

Myristica swamp associates (MSA)

There were 151 species that were MSA.  They had a POc value between 50 and 75.  This implies that they spend much of their time in and around the myristica swamps than outside it.  These included 37 Hesperiid species, 40 Lycaenids, 45 Nymphalids, 13 Papilionids, 14 Pierids and two Riodinids (Appendix I).  Eighteen taxa listed in the MSA category were found to be endemic species of which 11 species were strictly Western Ghat endemics (Table 2).  Two species were Red-Listed by IUCN and 29 species were listed in the various Schedules of the Indian Wildlife (Protection) Act, 1972 (WPA 1972) (Appendix I).

Stragglers

Forty-eight species were found to be stragglers; of them, three were endemics, three were in IUCN Red List and six species were listed in the WPA 1972.  Three species were endemics in the straggler category: Prioneris sita (Felder & Felder, 1865) is endemic to southern India and Sri Lanka, Eurema nilgiriensis (Yata, 1990) is endemic to the Western Ghats, and Rapala lankana (Moore, 1879) is restricted to Western Ghats and Sri Lanka (Western Ghats complex).  Hypolimnas misippus (Linnaeus, 1764) was listed under Schedule I & II, while Catapaecilma major callone (Fruhstorfer, 1915), Dophla evelina laudabilis Swinhoe, 1890 and Halpe hindu Evans, 1937 falls under Schedule II; Appias libythea (Fabricius, 1775) and Prioneris sita (Felder & Felder, 1865) were Schedule IV species under WPA, 1972.  Three species were in IUCN Red List in the Least Concern category – Junonia almana almana (Linnaeus, 1758), J. hierta hierta (Fabricius, 1798), and Eurema brigitta rubella (Wallace, 1867).

Host plant utilization

The complete list of plants of myristica swamps of the study area was obtained from Nair et al. (2007).  Eighty-one plant species recorded during the study were butterfly larval hosts in the myristica swamp.  Of these, 54 species of plants that we observed as larval hosts were already known larval host plants being used elsewhere for butterflies in the Western Ghats (Table 3).  We also found 27 species of new hostplant records being used by 43 species of butterflies (Table 4).

Conclusions

In our study, we found 206 species of butterflies from Papilionidae, Pieridae, Lycaenidae, Riodinidae, Nymphalidae, and Hesperiidae from myristica swamps of Shendurney.  Of these only seven species were MSD, which are restricted to the swamps of the region, and 23 species of butterflies were endemic to peninsular India of the Western Ghats complex.  With respect to WPA 1972, 32 species seen in the swamps are protected and seven species are in the Red List of IUCN.  It was noted that most of the butterflies were shared species with the nearby evergreen patches and only seven species were specifically partial to it.  We confirmed the presence of the rare Eurema nilgiriensis (Yata, 1990) Nilgiri Grass Yellow butterfly from Shendurney, extended its range into Agasthyamalais and have recorded Ventilago bombaiensis Dals., as its site-specific larval hostplant.  Eighty-one species of plants were recorded as butterfly larval hosts in the myristica swamp ecosystem, with 27 species being new host plant records for Western Ghats.  Interestingly, none of the butterflies recorded were using plants of myristicaceae family as larval hosts as far as it is known.  The POc is a simple index that can be easily applied to assess habitat association of any taxa.

Table 1. Percentage of occurrence (POc) of myristica swamp dependent butterflies.

Table 2. Endemic species among myristica swamp associate butterflies

Table 3. List of larval host plants for butterflies of myristica swamp forests, Shendurney WS, recorded from our observations from 2008–2018.

Table 4. Newly discovered larval host-plants for butterflies of Western Ghats, recorded from myristica swamp forests, Shendurney WS, during our study from 2008–2018.

For images / figures – click here

References

Ali, S.M., D. Chandran & T.V. Ramachandra (2008). Faunal assemblages in myristica swamps of central Western Ghats, Karnataka, India. Sahyadri e-news 2–13.

Anonymous (2012). Checklist of Butterflies of Shendurney, TNHS Thiruvananthapuram, in Management plan for Shendurney Wildlife Sanctuary, Kerala Forest Department. Government of Kerala.

Bell, T.R. (1909–1927). The Common Butterflies Of The Plains Of India (Including Those Met With In The Hill Stations of The Bombay Presidency). Journal of the Bombay Natural History Society 19(1)–31(4).

Blatter, E. & W.S. Millard (1997). Some Beautiful Indian Trees. Bombay Natural History Society. Oxford University Press, 2^nd Edition. 165pp., xxi Colour Plates.

Champion, H.G., & S.K. Seth. (1968). A Revised Survey of the Forest Types of India. Delhi. https://dds.crl.edu/crldelivery/23005.

Evans, W.H. (1932). Identifications of Indian Butterflies. 2nd edition Bombay Natural History Society, Madras. X + 454 pp., 32pl.

Gamble, J.S. (1967). The Flora of The Presidency Of Madras. Botanical Survey Of India. 1389pp.

IUCN (2018). The IUCN Red List of Threatened Species. Version 2018-2. http://www.iucnredlist.org. Downloaded on 3 December 2018.

Joyce, J., K.K. Ramachandran & P.V. Nair (2007a). A Preliminary Overview and Checklist of the Spider Fauna of myristica Swamp Forests of Southern Kerala, India. Bulletin of the British Arachnological Society 109: 12–14.

Joyce, J., K.K. Ramachandran, & P.V. Nair (2007b). Animal diversity of the myristica swamp forests of Southern Kerala with special reference to herpetofauna. In: The Proceedings of the 19^th Kerala Science Congress: 724–726.

Joyce, J., K.K. Ramachandran & P.V. Nair (2007c). A rare and little known lizard, Otocryptis beddomi from the myristica swamps of Southern Kerala, India. The Herpetological Bulletin 101: 27–31.

Joyce, J., T.J. Roby, K.K. Ramachandran & P.V. Nair (2014). Species abundance distributions of selected communities in the myristica swamp forests of southern Kerala. Current Science 107: 447–453.

Joyce, J., T.J. Roby, K.K. Ramachandran & P.V. Nair (2015). The state of myristica swamp forests in southern Western Ghats, India - butterfly species richness as an indicator. Indian Forester 141: 1056-–1066.

Kalesh, S. & S.K. Prakash (2007). Additions to the larval host plants of butterflies of the Western Ghats, Kerala, South India (Rhopalocera, Lepidoptera): Part 1. Journal of the Bombay Natural History Society.104: 235–238.

Kalesh, S. & S.K. Prakash (2015). Additions to the larval host plants of butterflies of the Western Ghats, Kerala, South India (Rhopalocera, Lepidoptera): Part 2. Journal of the Bombay Natural History Society 112: 111–114.

Krishnamoorthy, K. (1960). Myristica swamps in the evergreen forests of Tranvancore. Indian Forester 86(5): 314–315.

Kunte, K. (2000). Butterfles of Peninsular India. Universities Press (Hyderabad) and Indian Academy of Sciences (Bangalore), 254pp.

Kunte, K. (2006). Additions to known larval host plants of Indian Butterflies. Journal of the Bombay Natural History Society 103(1): 119–122.

Kunte, K., S. Sondhi & P. Roy (Chief Editors) (2018). Butterflies of India, v. 2.37. Indian Foundation for Butterflies. http://www. ifoundbutterflies.org/. Accessed 14 March 2018.

Larsen, T.B. (1987). The butterflies of the Nilgiri mountains of southern India (Lepidoptera: Rhopalocera). Journal of the Bombay Natural History Society. 84(2):291–316.

Mathew, G., R. Chandran, C.M. Brijesh & R.S.M. Shamsudeen  (2004). Insect fauna of Shendurney Wildlife Sanctuary, Kerala. Zoos’ Print Journal 19(1):1321–1327; https://doi.org/10.11609/JoTT.ZPJ.19.1.1321-7

Nair, P.V., K.K. Ramachandran, K. Swarupanandan & P. Thomas. (2007). Mapping biodiversity of the myristica swamps in southern Kerala. Research Report, KFRI, Peechi, Kerala. 255pp.

Nayar, T.S., A.R. Beegam, N. Mohanan & G. Rajkumar (2006). Flowering Plants Of Kerala – A Handbook. Tropical Botanic Garden And Research Institute, Trivandrum, Kerala. 1069pp.

Nitin, R., V.C. Balakrishnan, P.V. Churi, S. Kalesh, S. Prakash & K. Kunte (2018). Larval host plants of the butterflies of the Western Ghats, India. Journal of Threatened Taxa 10(4): 11495–11550; https://doi.org/10.11609/joTT.3104.10.4.11495-11550   

Ramabhat, P. & K.M. Kaveriappa (2009). Ecological studies on myristica swamp forests of Uttara Kannada, Karnataka, India. Tropical Ecology 50(2): 329–337.

Ramarao, M. (1914). Flowering Plants of Travancore. International Book Distributors, 495pp.

Ravi, N. & N. Mohanan (2004). Common Tropical & Subtropical Sedges and Grasses – An Illustrated Account. Oxford & IBH. 220pp.

Renuka, C. (2000). Field Identification Key for Rattans Of Kerala. Kerala Forest Research Institute & Kerala Forest Department. 33pp.

Robinson, G.S., P.R. Ackery, I.J. Kitching, G.W. Beccaloni & L.M. Hernández (2001). Hostplants Of The Moth and Butterfly Caterpillars of The Oriental Region. The Natural History Museum, London. 744pp.

Roby, T.J. & P.V. Nair (2007). Myristica swamps - a prime habitat of the critically endangered tree Syzygium travancoricum. In: The Proceedings of the XVIII Kerala Science Congress 764–765.

Roby, T J., J. Joyce & P.V. Nair (2014). Checklist of Flora of Myristica Swamps - A Critically Endangered Fresh Water Ecosystem of Southern Western Ghats of Kerala, India. Indian Forester 140: 608–616.

Rodgers, W.A. & H.S. Panwar (1988a). Planning wildlife protected area network in India. The Report. A report prepared for the Department of Environment, Forests and Wildlife, Government of India at Wildlife Institute of India, Vol I: 341pp.

Rodgers, W.A. & H.S. Panwar. (1988b). Planning wildlife protected area network in India. State Summaries. A report prepared for the Department of Environment, Forests and Wildlife, Government of India at Wildlife Institute of India, Vol II: 267pp.

Seethalakshmi, K.K. & M.S.M. Kumar (1998). Bamboos of India: a Compendium. Kerala Forest Research Institute, Peechi, Kerala and International Network For Bamboo And Rattan, Beijing, 342pp.

Sevastopulo, D.G. (1973). The foodplants of Indian Rhopalocera. Journal of the Bombay Natural History Society. 70(1): 156–83.

Sinu, P.A. & M.V. Sharma (2013). Insect functional guilds in the flowering canopy of myristica fatua in a lowland swamp, central Western Ghats, India.Tropical Conservation Science - Special Issue 6(5): 653–662.

Sivarajan, V.V. & P. Mathew (1997). Flora of Nilambur (Western Ghats, Kerala). Bishen Singh Mahendra Pal Singh, Dehradun, 900pp.

Sreejith, K.A., U.M. Chandrashekara, T.K. Nirmesh & V.B Sreekumar (2016). Tree species composition and distribution pattern in a myristica swamp of northern Kerala, India. Current World Environment 11(3): 743–750.

Subash C.M.D., D.K. Mesta, G.R. Rao, S. Ali, K.V. Gururaja & T.V. Ramachandran (2008). Discovery of two critically endangered tree species and issues related to relic forests of the Western Ghats. The Open Conservation Biology Journal 2: 1–8.

Subramanian, K.N. (1995). Flora of Thenmala (and its environs.). International Book Distributors, Dehra Dun, 516pp.

Varghese, A.O. & M.A.R.R. Menon. (1999). Floristic composition, dynamics and diversity of myristica swamp forests of southern Western Ghats of Kerala. Indian Forester 125(8): 775–783.

Appendix 1. A checklist of butterflies of myristica swamps of Shendurney WS, Kollam, Kerala.

Key: STR: Straggler, SL: Sri Lanka, Sh: Schedules of Indian Wildlife (Protection) Act, 1972.