Range extension and larval habitat of Lyriothemis tricolor Ris , 1919 ( Odonata : Anisoptera : Libellulidae ) from southern Western Ghats , India

1 Centre for Conservation Ecology, Department of Zoology, M.E.S. Mampad College, Malappuram, Kerala 676542, India 1,5 Wildlife Research and Conservation Trust, Anupallavi, Chungathara P.O., Malappuram, Kerala 679334, India 2 Zoological Survey of India, Prani Vigyan Bhavan, M-Block, New Alipore, Kolkata, West Bengal 700053, India 3,4 Western Ghat Regional Centre, Zoological Survey of India, Jafer Khan Colony, Kozhikode, Kerala 673006, India 5 Environmental Impact Assessment Division, Sálim Ali Center for Ornithology and Natural History, Anaikatty P.O, Coimbatore, Tamil Nadu 641108, India 1 dasksa@gmail.com, 2 subbuka.zsi@gmail.com (corresponding author), 3 kgemily@gmail.com, 4 palot.zsi@gmail.com, 5 nishadhka@gmail.comt


INTRODUCTION
Aquatic habitats in tree holes are one of the four broad categories of phytotelmata.They are known to support diverse insect orders including Odonata (Orr 1994;Kitching 2000).Worldwide 24 genera and 47 species of Odonata are known to make use of phytotelmata (Corbet 1999).The phytotelmata as a larval habitat has been reported from all major tropical biogeographic regions of the world except the Indian subcontinent (Corbet 1999).Here we report for the first time, the use of phytotelmata as a larval habitat in India by Lyriothemis tricolor Ris, 1919 and a range extension for this species from the Western Ghats.

STUDY AREA
The current discovery is based on field studies conducted at Silent Valley National Park (SVNP) in Palakkad District, New Amarambalam Reserved Forest (NARF), Malappuram District and Salim Ali Bird Sanctuary (SABS), Thattekkad in Ernakulam District of Kerala Western Ghats (Image 1).Studies at SVNP and NARF were conducted from December 2009 to September 2010 and at SABS in April 2013.The details of vegetation types and the bioclimatic features of the study area are provided in Table 1.

METHODS
The larvae from SVNP and NARF were collected by the first author and junior co-author in 2010 as part of a study which investigated the insect communities in tree holes (Nishadh & Das 2012).A total of 150 tree holes were sampled from three regions of the SVNP, namely, Sairandhri (n=68), Poochippara (n=34) and Walakkad (n=35) whereas in NARF tree holes were mostly sampled from Panapuzha (n=13) (Image 2).
The physical and structural characteristics of tree holes were documented as follows.For every tree hole sampled, the following were recorded: tree species, height of the tree hole from the ground, GBH of the tree, tree hole diameter measured as two longest hole opening measurements perpendicular to each other (Sota 1998), depth and water volume.
Water in a tree hole was extracted using siphoning, Image 1. Study area showing collection localities of the larvae and adult.
and volume was measured using a measuring cylinder.
The contents of the tree hole such as leaf litter and detritus were transferred to a plastic tray and thoroughly checked for the presence of life forms.Thorough checks were made with the aid of a flashlight for elusive organisms in tree hole crevices.The water contents were then sieved with successive sieves from coarse to finer sieves (cc-500μm sieve size) by holding in a plastic tray.The organisms were counted and morpho-species preserved in 5% formalin (Yanoviak & Fincke 2005).The collected specimens were sorted out and identified to possible taxonomic level of family or genus referring to Edmondson (1959).Physicochemical parameters of the water from the tree hole were studied based on Greenberg et al. (1992).Water samples from tree holes were collected using a suction rubber bulb, tube and stored in laboratory cleaned bottles.The samples were taken to the laboratory and analysed immediately.pH, electrical conductivity (EC, μS/cm), total dissolved solids (TDS, ppt), phosphate (mg/l), nitrate (mg/l), turbidity (FAU), sulphate (mg/l), and ammonia concentrations were analysed following standard methods (Greenberg et al. 1992).
During a faunistic survey at SABS, on 03 April 2013, a female specimen was collected from Anachathapara area of the sanctuary.A freshly emerged female specimen with exuvia was sighted on the bark of a Lannea coramandelica (Houtt.)tree at a height of about 5m from the ground (Image 3).The collection locality is primarily a degraded semi-evergreen forest, interspersed with Mahogany and Teak plantations.The area is very close to the lake formed by the Boothathankettu Dam.We observed the specimen in a bottle for 10 days.Initially the specimen was pale yellow in colour with light brown markings on the head.After two days the colour drastically changed to darker and brighter.
The Anisopteran larvae collected from SVNP were identified up to the genus level following keys of, Xiufu (1994).Collected Lyriothemis larvae were compared with published descriptions of larval stages of Lyriothemis species (Lieftinck 1962;Lien & Matsuki 1979;Kitching 1986;van der Poorten 2009).The adult collected from SABS was identified based on keys of Fraser (1936) and van der Poorten (2009).The larvae were studied and compared with the exuvia collected from SABS.Body measurements and morphological characters of exuvia and larvae were studied under Leica EZ4HD and M205A microscopes.

RESULTS
The adult female collected from SABS was identified as Lyriothemis tricolor Ris, 1919 based on descriptions of Fraser (1936).The morphological characters of the larvae matched the descriptions of Lyriothemis tricolor Ris, 1919 (Lien & Matsuki 1979).However, the larvae had nine palpal setae instead of eight as described by Lient & Matsuki 1979.The morphological characters of the exuvia also matched that of larvae collected from SVNP and NARF which were also identified as belonging to that of Lyriothemis tricolor Ris, 1919.The detailed Images 4-8.Adult female (4-6) and exuvia (7-8).Description (Images 9-16): Larvae are uniformly rusty brown in colour and covered with short light brown hairs.Overall body texture is rough.Eyes are conical and pointed outwardly with metallic brown gloss under preserved condition.Antenna is eight segmented with 4 th segment being the longest.Prementum of labium is an elongated pentagon with two anterio-lateral ovoid projections.Apex of the prementum ends in a tuberclelike projection.The inner side of the prementum has 11 premental setae on either side.Palpal lobe is shovel-shaped with nine palpal setae.The anterior end of the palpal lobe has a thick spine.The occiput of the head has nine bald oval patches.In larva-01 the forewing pads extend to the 3 rd abdominal segment and in larvae 02 and 03 it reaches up to the 6 th abdominal segment.The legs are short and abdomen is ovoid.A single row of dorsal spines present from abdominal segments 3-9.The lateral spines of segment 9 reach half the length of paraproct.The cerci are shorter than epiproct and praproct is longer than epiproct.The measurements of larvae are provided in Table 2.

Habitat ecology
A total of 18 larvae of L. tricolor were collected from 15 tree holes of Sairandhri (n=8), Poochippara (n=3), Walakkad (n=0), Aruvanpara (n=4) and Panapuzha (n=3).Due to logistic reasons in the field, no attempt was made to raise the larvae to adulthood.Out of 150 tree holes sampled at an altitude range of 40-1175 m, only 10% of tree holes were occupied by the larvae of L. tricolor.No larvae were found in tree holes from Walakkad, SVNP.The tree holes with Odonata larvae were distributed from 600m to 1056m.The structural, water quality and associated biotic communities of the tree holes with the Odonata larvae are provided in Tables 3-6.Since many of the tree holes were remotely located in the forests or samples collected during the rainy days, it

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was not possible to take back the water sample to the laboratory for analysis.Hence these water samples were not analysed for physical and chemical properties.
Tree holes without water quality data are indicated in the tables.All the larvae were collected between March and September 2010 from host trees such as Tetrameles nudiflora R. Br. (Tetramelaceae), Elaeocarpus tuberculatus Roxb.
Physicochemical parameters of water collected from the tree holes show that the water is generally acidic with high levels of total dissolved solids, phosphates, sulphates and nitrates.The pH varied from extremly acidic to (pH 3.56) to near neutral (pH 6.48).
A diverse community of invertebrates and vertebrates coexist with L. tricolor larvae (table 6).Larvae and adults of Coleoptera and Diptera were very common in the tree holes.Three tree holes had frogs (Microhylidae: Ramanella sp.) and earthworms.Nematodes, and crabs were found only in one tree hole.It is not known how the different taxa interact in the community.However, the presence of predatory larvae of L. tricolor may significantly influence the community structure of tree holes.
Recently a new species Lyriothemis defonsekai was reported from Sri Lanka (van der Poorten 2009) and the range of L. acigastra was extended to the Western Ghats (Emiliyamma et al. 2013).Within its geographical range in Asia, L. tricolor was known to occur only up to 26 0 N & 89 0 E in Rajabhatkhawa in Buxa Tiger Reserve, West Bengal (Fraser 1936).Our discovery of this species from the southern Western Ghats extends the eastern range of the species to 11 0 N & 76 0 E in the Indian subcontinent.
The larvae and exuvia of L. tricolor collected from Western Ghats has nine palpal setae and 11 premental setae similar to that of L. elegantissima Selys, 1883 (Lien & Matsuki 1979).However, the final instar larvae of L. elegantissima is much smaller (17.6-19 mm) than the L. tricolor larvae (21.5-24 mm) (Lien & Matsuki 1979).Moreover, the characters of adult female match that of L. tricolor and L. elegantissima is not distributed in the oriental region.Hence, L. elegantissima is excluded and the variation observed in premental and palpal setae of L. tricolor from Western Ghats may be due to intraspecific variation of different disjunct populations of the Indian subcontinent.Long isolation of populations may have favoured some genetic changes such as changes in the number of premental and palpal setae.Genetic studies are required to ascertain taxonomic status of Western Ghats populations of L. tricolor.
These recent discoveries highlight the disjunct distribution of the genus within the Indian subcontinent.It has been proposed that the disjunct distribution of the genus in the southern part of the subcontinent is caused by passive or active wind dispersals (Laidlaw 1951;Dijkstra 2007) or movement along corridors along the east coast of India during the Pleistocene (Laidlaw 1951).In the Western Ghats, in addition to Lyriothemis, libellulids such as Hylaeothemis indica Fraser, 1946, Epithemis mariae (Laidlaw, 1915) and the recently discovered Lyriothemis acigastra (Selys, 1878) (Emiliyamma et al. 2013) are found exclusively in lowland forest swamps.Zygopteran species such as Phylloneura westermanni (Selys, 1860), Melanoneura bilineata Fraser, 1922 andCalocypha laidlawi (Fraser, 1924) are also restricted to such forest swamps.Currently, these forest swamps and associated odonates are found in small patches in the north and south of the Palakkad gap.Lowland forest swamps once existed extensively throughout the southern Western Ghats.They were drained, deforested and converted for agriculture during early human colonization (Chandran 1997).The extent of lowland forest swamps and associated odonate species are highly fragmented in the Western Ghats.
Recent palynological studies provide evidence that species-rich rain forests and swamps were once widespread in the Indian subcontinent during early palaeogene times (Prasad et al. 2009).After India-Asia collision during the quaternary and recent times, climate changed dramatically and the subcontinent became much drier climatically, leading to the disappearence of wet forests in most parts of peninsular India.
Wet forests with a dominance of Dipterocarpaceae disappeared from most parts of peninsular India during the cenozoic period (Shukla et al. 2013).However, the southern Western Ghats, with its unique topographic features, high precipitation and shorter periods of dry months provided refugia to sustain lineages of ancient tropical vegetation (Prasad et al. 2009).The existence of many ancient lineages of amphibians, fishes, reptiles and odonates in the southern Western Ghats also support the palynological evidence that this part of the Western Ghats was a rainforest refugia during the drier Pleistocene period when most of the tropical rainforests from other parts of the subcontinent disappeared (Abraham et al. 2013).Extant species of Lyriothemis in the southern Western Ghats and Sri Lanka may in fact be the relict populations of Palaeogene times when tropical rainforests and forest swamps extensively covered the subcontinent and not wind dispersals or migration through land corridors as suggested earlier (Laidlaw 1951;Dijkstra 2007).However, detailed molecular phylogenetic studies are required to further investigate this hypothesis.
Larvae of Lyriothemis tricolor being a predator in the tree hole community, may play a significant role in structuring the community composition of tree hole breeding insects.Studies on L. cleis at Sulawesi (Kitching, 1986); L. tricolor and L. elegantissima at Taiwan (Lien & Matsuki 1979) suggest that they act as top level predators within treehole food web (Kitching 1986).Similarly, L. cleis larvae were observed in Bornean rain forest tree hole aquatic habitat (Orr 1994).The breeding habitat of L. tricolor is very different from the other species of the Western Ghats.The larvae live in extreme conditions where the pH is as low as 3.6 and with high levels of total dissolved solids, phosphates, sulphates and nitrates (Paradise 1997).High levels of nutrients and low pH is also reported from other tree hole aquatic medium such as in North America (Paradise & Kuhn 1999), Panama (Yanoviak 1999) and Germany (Schmidl et al. 2008).This is due to degradation of litter and and woody debris.Studies have shown that tree hole inhabiting larval species, especially the Odonata have a broad range of chemical tolerance (Fincke 1999;Yanoviak 1999).
This indicates the specialization of larvae to survive in extreme water quality conditions.The low pH also might influence the growth of certain key inhabitants and impact community interactions by affecting the processing chain commensalisms that occur in tree hole aquatic habitats.Therefore, the usability of tree hole habitats can be considered as a bio-indicator of forest ecosystem towards acidic deposition (Paradise & Dunson 1997).The limited availability of suitable tree holes with the right microhabitat and climatic conditions may significantly influence the distribution of L. tricolor within the Western Ghats.The discovery of a tree hole breeding dragonfly highlights the importance of tropical forests in conserving Odonata fauna of the Western Ghats and also emphasises the need to consider the larval habitats in conservation action plans.
16. Palpal lobes of larvashade medially; postclypeus bright yellow with median oval dark brown mark and dark brown edges; anterior surface of frons bright yellow, upper surface of frons and vesicle metallic green; occiput shining black; clypeus and frons with black hairs.Eyes: Reddish-brown above, bright yellow below and on sides.Prothorax: Yellow with pale brownish shade at the middle lobe.Thorax: dorsum with broad brownish shade; humeral suture with a broad black stripe; two short, oval antehumeral yellow spots as in male; laterally yellow with a thin brown stripe on mesepimeron and a similar stripe on posterolateral suture; tergum yellow; underneath thorax bright yellow with a brownish-black transverse stripe at the middle.Legs: black; all coxae yellow; trochanters yellowish brown.Wings: transparent, extreme base (anal field),

Table 5 . Physicochemical properties of tree hole water
Legend: ORP -Oxidation reduction potential; CON -Electrical Conductivity; TDS -Total dissolved solids; n/a -data not available