New distributional records of fireflies (Coleoptera, Lampyridae, Luciolinae) from two Eastern States of India with notes on their biology and an updated Indian checklist

Abstract Background The subfamily Luciolinae Lacordaire, 1857, a group of flashing fireflies, is composed of approximately 400 described species in the world. Though the taxonomy of this group has been fairly well established in Southeast (SE) Asia and the Australopacific Region, there is scope of gathering further information regarding taxonomic knowledge on this group from India. Until now, 32 Luciolinae species from nine genera have been reported from India, which is only about 8% (32 out of 400) of the world Luciolinae fauna. With this in mind, several faunistic surveys were conducted in Odisha and West Bengal States of India to explore the firefly fauna of the two States. New information The faunistic surveys conducted in the Odisha and West Bengal States of India have revealed six new distributional records of Luciolinae firefly species belonging to the genera Abscondita Ballantyne, Lambkin & Fu 2013, Asymmetricata Ballantyne 2009, Pteroptyx Olivier 1902 and Sclerotia Ballantyne 2016 in the two States, earlier which were recorded from other States of India. Of the already recorded species, Abs.perplexa is recorded for the first time from both the States, whereas Abs.chinensis, Asy.ovalis and Scl.aquatilis present new records for Odisha State and Pt.malaccae and Scl.substriata for West Bengal State. The newly-recorded taxa are presented with their examined materials, diagnoses and brief biological notes. Some more distinguishing characters were added for the male genitalia of Abs.perplexa and Asy.ovalis. Further, a checklist of Luciolinae firefly species already recorded from India is also presented.

It is with this background that several faunistic surveys for Luciolinae fireflies have been conducted in two eastern States of India (Odisha and West Bengal) during February 2017 to March 2020.The survey results also confirmed the further occurrence of the abovementioned species in India and in these two States.Additionally, Abs.perplexa is recorded for the first time from both States, whereas Abs.chinensis, Asy. ovalis (Gorham 1880, Ballantyne et al. 2013, Ballantyne et al. 2016, Ballantyne et al. 2019).
Moreover, an Indian checklist (Table 1) of Luciolinae fireflies is also compiled mostly on the basis of Ballantyne et al. (2019) and all other available literature including the publications (Das and Dev Roy 1989, Sengupta and Mukhopadhyay 1990, Kacker 1993, Agarwal and Ghose 1995a, Agarwal and Ghose 1995b, Agarwal and Ghose 1995c, Majumder and Dey 2005, Mitra 2005, Roy and Nandi 2012) of the Zoological Survey of India (ZSI) and the records (Kapur 1955) of the Indian Museum.

Study sites
The surveys were carried out in selected study sites of the two eastern States of India (Fig. 1), representing contrasting characteristics with respect to habitat, ecological attributes and anthropogenic interaction types and levels.The study sites are: Tropical moist deciduous forest of Kuldiha Wildlife Sanctuary and its associated areas.Located in the Balasore District of Odisha State, the site is spread over an area of around 272.75 km and exhibits a typical mixture of semi-evergreen riparian forests, peninsular (coastal) Sal Forest (Shorea robusta) and tropical moist deciduous forest.
Coastal zone of Chandipore.Situated along the Bay of Bengal in the northern part of the east coast of India in the Balasore District of Odisha State, the site represents typical marshy tidal flat with sandy alluvial soil type.

Mixed dry deciduous vegetation patch of Keonjhar.
The site exhibits tropical mixed dry deciduous vegetation with underneath granite rocks and its metamorphs consisting of significant mineral assets like iron ore, manganese and chromites.
Himalayan foothills of Darjeeling.The site has a characterised substratum with sandstone and conglomerate formations, horizontal layers of unconsolidated sand, silt, pebbles and gravel, covered with tropical deciduous vegetation prominently represented by Sal trees.

Southern Gangetic plains.
The site has deltaic alluvial soil characterised by evergreen vegetation and prevalent humid climate.
Mangrove forests of Sundarban Biosphere Reserve.The site represents various islands having typical mangrove patches and areas with reclaimed land forms.

Gurguripal Eco Forest.
The site is a forest-based rural area with highly eroded red lateritic soil with tropical evergreen and mixed deciduous Sal Forest.
Coastal alluvial plain of Egra.Situated in the lower part of the coastal tract in West Bengal, the area is covered by alluvial plains with scarcely distributed halophytic vegetation.

Material deposition
The specimens are deposited in the entomological collections of the Ecology Laboratory of the Department of Zoology, Vidyasagar University (VUEC), Midnapore (West), West Bengal, India.

Diagnosis
Length 8-10 mm; Width 2.8-3.2mm; Abs.chinensis is one of the three species of Abscondita (Abs.chinensis, Abs.perplexa and Abs.terminalis) present in India, which is characterised by the pale dorsum with dark brown to black elytral apices (Fig. 2).PN, MS, ventral thorax and elytra pale brown with the elytral apices black and occupying approximately 1/6 of its total length, MN pale yellow, antennae and palpi dark brown, terminal abdominal tergites dark brown, ventral abdomen brownish-yellow, white LO on V6 and V7, legs brownish-yellow with the tips of tibae and tarsi dark brown.The species can be distinguished from other Abscondita species known from India by the following set of male characters: completely dark brown V5 (in Abs.perplexa and Abs.terminalis, the V5 is partly dark along the posterior margin only).Male genitalia (Fig. 3): Aedeagal sheath sternite terminated into two apically acute divergent lobes (in Abs.perplexa and Abs.terminalis, aedeagal sheath sternite is terminated into two apically rounded lobes); ML shorter than LL, gradually narrowed towards the apex, with the tips of LL blunt and extended beyond the tip of ML (in Abs.perplexa, both LL are longer than ML and the tip of ML is projecting beyond the tips of LL).

Biology
Adults of Abs.chinensis generally prefer open forested and grassland areas.These fireflies emit a luminescent flashing pattern, particularly during their mating season in early monsoon.During flight, males generally achieve an average height of 2 to 3 metres in forest and grassland habitat.Females answer to male courtship flashes from the substratum level or from the perching sites on ground vegetation.Bioluminescent larvae, which are terrestrial and inhabit places near aquatic bodies, show a carnivorous diet pattern and sometimes also cannibalism particularly when there is a scarcity of food (Ballantyne et al. 2013).

Diagnosis
Length 7-10 mm; Width 2.5-3.5 mm; Abs.perplexa is one of the three species of Abscondita (Abs.chinensis, Abs.perplexa and Abs.terminalis) present in India which is characterised by a pale dorsum with dark brown to black elytral apices (Fig. 4).PN, MN, MS and semi-transparent elytra pale brown, with the elytral apices black and occupying approximately 1/6 of its total length, head between eyes, labrum, antennae, palpi, apical part of tibiae and all tarsi dark brown, ventrites yellowish-orange, V6 and V7 occupying white LO.The species can be distinguished from other Abscondita species known from India by the following set of male characters: terminal abdominal tergites pale yellow (in Abs.chinensis and Abs.terminalis, abdominal tergites are dark brown), V5 bearing a medially notched and laterally broad dark patch along the posterior margin (in Abs.chinensis, the V5 is entirely dark).Male genitalia (Fig. 5): Aedeagus twice as long as wide (L:W = 0.5:0.25);ML longer than LL, gradually narrowing towards the apex, with the tip of ML projecting beyond the tips of LL (in Abs.chinensis and Abs.terminalis, both LL are longer than ML and the tip of ML is not projecting beyond the tips of LL), ML broader at base than LL; BP sclerotised, concave at its inner margin; LL subparallel-sided and fused with ML along most of the dorsal length, except in the separated apical 1/5 part; aedeagal sheath sternite terminated into two apically rounded lobes (in Abs.chinensis, the sheath sternite is terminated into two apically acute divergent lobes).

Biology
Adults of Abs.perplexa generally prefer open grassland area, but are also found on vegetation patches, near aquatic sites.Their oviposition sites include leaf litter or dry leaf beds.Larvae are nocturnal, glow weakly and were observed on plant debris and leaf litter in terrestrial habitats (Ballantyne et al. 2013).

Notes
This is a tentative identification, based solely on morphology.

Diagnosis
Length 9-9.5 mm; Width 3.2-3.5 mm.Ventral thorax yellow, V3-V5 dark brown, LO white, legs yellow with the apical part of tibiae and all tarsi dark brown (Fig. 6).Asy.ovalis can be distinguished from other species of the genus by the following set of male characters: elytra dark brown to black with the sutural and lateral margins pale yellow (Asy.bicoloripes is with pale yellowish-brown dorsum, elytra pale brown bearing dark brown basal and apical parts in Asy.humeralis); PN brownish-orange (in Asy.humeralis, there are paired median dark spots on pronotum); V6 and V7 having white LO with the LO in V7 bipartite (whereas LO is entire in Asy.circumdata); base of PN bisinuate; ASD < ASW; apex of MPP narrowly rounded.Male genitalia (Fig. 7): Aedeagus longer than wide (L/W =1.8); LL are of equal length and slightly shorter than ML (length of LL/length of ML = 0.6), asymmetrical, inner lateral margin of LL diverging from ML for about 4/5 of their length, outer lateral margin sinuate, apex of right LL outturned, LL apex width greater than ML apex width, ML pointed and little produced beyond LL, BP hooded with its margin facing ML and LL, concave and covering the basal parts of ML and LL; aedeagal sheath L/W= 3.75, posteriorly symmetrical and subparallel-sided, posterior margin of sheath sternite broad and slightly asymmetrically emarginated, anterior part of sternite apically rounded; lateral arms of sheath tergite extended narrowly to the anterior sides of sheath sternite.

Biology
Adult males of Asy.ovalis were found flying at a height of around 5 metres, often reaching the mid-to upper canopy level in forest habitat.Some of these were collected when they came down by sweep net and identified in the laboratory.Females and larvae are terrestrial (Ballantyne andLambkin 2009, Ballantyne et al. 2019).

Diagnosis
Length 5-6.5 mm; Width 1.5-1.8mm; PN, MN and MS brownish-yellow, thorax ventrally yellowish-orange, elytra bright brownish-yellow with its apices black, head between eyes, antennae and palpi dark brown, legs brownish-yellow with the tibae and tarsi brown, terminal abdominal tergites yellow, ventrites brownish-yellow, tip of PLP brown, V6 and V7 having white LO with the LO in V7 bipartite (Fig. 8).Pt. malaccae can be distinguished from other species of the genus by the following set of male characters: apex of FS1 strongly produced laterally; elytra almost parallel-sided with its apices deflexed and lacking depressions (Pt.gelasina possesses depressions at the elytral apices); elytral apices twice as long as wide (Pt.truncata, in contrast, bears comparatively shortened elytral apices); hind-tibae expanded; posterior margin of T8 without lobes; V7 with a broad and deep semicircular emargination along its posterior margin separating the MPP and PLP, with the PLP slenderly produced (PLP is comparatively narrower in Pt. gelasina and, in Pt. maipo, Pt. sulawesiensis and Pt.valida, the PLP of V7 are scarcely produced and broadly rounded).Male genitalia (Fig. 9): Aedeagus slender, elongated, symmetrical, aedeagus b/a 0.9, LL are of equal length, slightly shorter than ML, separated by half of their dorsal length, lack lateral hairy appendages and slender leaf-like projections along their outer ventral margins and inner margins respectively, ML symmetrical, narrow and tube-like, not bearing paired lateral teeth and without ventral inclination, BP bluntly pointed, lightly sclerotised; aedeagal sheath symmetrical, apically rounded, aedeagal sheath sternite relatively narrower at the anterior half, widest at the middle and tapers almost symmetrically towards an entire narrow apex, paraprocts bulbous, L/W = 3/1.

a b
Figure 8.

Diagnosis
Length 9-11 mm; Width 3.5-4 mm; PN, MN and MS pale brownish-yellow, elytra dark brown with the sutural and lateral margins bright yellow, ventrites pale brown, legs pale brown with the apical parts of tibae and entire tarsi dark brown (Fig. 10).Scl.aquatilis can be distinguished from Scl. substriata (the other known species of the genus from India) by the following set of male characters: V4 and V5 having dark brown patches along the posterior margin with the dark patch of V5 occupying approximately 2/3 of the part posteriorly (in case of Scl.substriata, whole part of V4 and V5 dark brown in colour); LO occupies the entire V6 and V7, except for a small median emargination at the anterior part of V7 (in case of Scl.substriata, the anterior median emargination of the LO in V7 is of comparatively greater depth).Male genitalia (Fig. 11): Aedeagus L/W 2.1, aedeagal sheath sternite having an oblique bar and a small median posterior emargination, anteromedian margin of sheath tergite emarginated (in case of Scl.substriata, the transverse oblique ridge in posterior half of sheath sternite is not present, elongate pointed projection of the right side of the posterior margin of the sheath sternite is not found and there is rounded prolongation of the median anterior margin of the aedeagal sheath tergite); Sclerites (Fig. 11a, b) -distal end of triangular-shaped ventral sclerite is rounded in shape, its margin is not sclerotised, anterolateral corners acute; right sclerite possesses three projections to the right, of those, the posterior one apically acute, median one is dorsolaterally inclined with the apical end slender and rounded, the third one is the longest, arises in an emargination between the other two, ventrolaterally inclined with rounded hollow apex; left sclerite also possesses three arms, all of which are apically rounded with the anterior one expanded.

Biology
Males of Scl.aquatilis were found perching on macrophyte surfaces at the onset of darkness.Their average flight height ranged between 2 to 5 metres.Females are macropterous.Metapneustic larvae are exclusively aquatic in nature and the later instars lack gills, while in initial instars, lateral bristles function as gills (Fu and Ballantyne 2009).The 1 -2 instar larvae obtain dissolved oxygen through tracheal gills, whereas the 3 -6 instar back-swimmer larvae, without tracheal gills, swim just below the water surface and expose their abdominal segments to air to breath by their terminal spiracles (Fu et al. 2005, Zheng et al. 2008)

Diagnosis
Length 8.4 mm; Width 3.8 mm; PN, MN and MS yellowish-orange, elytra light greyishbrown with its apices black tipped and lateral and sutural margins bright yellow, legs yellow with the apical parts of tibae and entire tarsi brownish-black (Fig. 12).Scl.substriata can be distinguished from Scl. aquatilis (the other known species of the genus from India) by the following set of male characters: V3, V4, V5 brownish-black (in case of Scl.aquatilis, V4 and V5 having dark brown patches along the posterior margin with the dark patch of V5 occupying approximately 2/3 of the part posteriorly), LO occupies the entire V6 and V7, with the V7 having a moderately deep (approximately 1/3 of V7 length) median emargination at its anterior margin (in case of Scl.aquatilis, a small median emargination at the anterior part of V7).Male genitalia (Fig. 13): Aedeagus L/W 2.1, aedeagal sheath sternite bears no oblique median ridge at posterior part and anteromedian margin of sheath tergite with rounded prolongation (in case of Scl.aquatilis, aedeagal sheath sternite having an oblique bar and a small median posterior emargination, anteromedian margin of sheath tergite emarginated); Sclerites (Fig. 13a New distributional records of fireflies (Coleoptera, Lampyridae, Luciolinae) ... projection which is hollow and apically rounded; at its side, there lies a curved anteriorly pointed projection, minute lateral projections become fused and lie behind and beneath both of ventral and right sclerites as a broad piece with irregular lateral margins; left sclerite has three lateral slender and pointed projections, the inner arm of median and posterior projections are curved and apically pointed.

Biology
Males of Scl.substriata were found in flight up to canopy heights of 6 to 7 metres and over macrophyte surfaces during nocturnal hours.On shining of a bright light, the individuals stop flying and drop.Females are macropterous.Metapneustic larvae are exclusively aquatic in nature and the later instars lack tracheal gills, while in initial instars, lateral bristles function as gills (Fu and Ballantyne 2009).The 1 -2 instar larvae obtain dissolved oxygen through tracheal gills, whereas the 3 -6 instar backswimmer larvae, without tracheal gills, swim just below the water surface and expose their abdominal segments to air to breath by their terminal spiracles (Fu et al. 2005, Zheng et al. 2008).Adult individuals were found near aquatic sites.

Discussion
The present faunistic report, based on the occurrence and distribution of fireflies in the two eastern States of India, reflects that a number of firefly species, having wider distribution throughout SE Asia, also inhabit diverse habitat types (grassland, forest, marshy area, roadside vegetation patches etc., as mentioned in the description of the study sites), which include Abs.chinensis, Abs.terminalis, Pt. malaccae and Asy.ovalis.These species were reported earlier from a number of countries in this geographical subregion of South Eastern and Southern Asia.On the contrary, species like Abs. perplexa (Cambodia, India, Sri Lanka), Asy.humeralis (India, Indonesia, Sri Lanka), Scl.aquatilis (India, Laos, Thailand, Vietnam) and Scl.substriata (India, Myanmar, Sri Lanka)   3 Abscondita terminalis (Olivier, 1883) West Bengal; Odisha (Ghosh et al. 2021).
In the present study, the recorded firefly species show diversified habitat preferences.Of all the study sites, mangroves of Sundarban Biosphere Reserve support the highest diversity of Luciolinae species, providing necessary environmental resources like wetland association, vegetation compositions and shelter for larvae and adults.During our field study, we found that dependence on display plants and association with wetlands are prominent factors influencing abundance and distribution of firefly species.

Figure 1 .
Figure 1.Map of the study area indicating collection points of newly-recorded species (India in inset highlighting the two eastern States).
, b) -ventral sclerite almost circular with asymmetrically thickened ventral surface, a curved band lying in the middle; right sclerite bears anterior ventral st nd rd th
and Scl.aquatilis present new records for Odisha State and Pt.malaccae and Scl.substriata for West Bengal State.Until now, Abs.perplexa had records from Assam and Madhya Pradesh States, Abs.chinensis from Assam, Bihar, Maharashtra and West Bengal States, Asy.ovalis from Goa and West Bengal States, Pt. malaccae from Tamilnadu State, Scl.aquatilis from Maharashtra and West Bengal States and Scl.substriata from Assam and Maharashtra States
Lanka (Wijekoon et al. 2021ailand;Rahman 2021)genusLuciolaand he had(McDermott , Wattanachaiyingcharoen et al. 2016, Wijekoon et al. 2016, Seri and Rahman 2021)ott's arrangement, species identification and taxonomy of Luciola was imprecise and leading to many erroneous grouping and taxonomic instability(Ballantyne et al. 2019, Jusoh et al. 2021).To provide an appropriate taxonomic framework for the Luciola fauna of the SE Asia and the Australopacific Region and also to define what Luciola s. str.could contain,Ballantyne et al. (2019)andJusoh et al. (2021)addressed and defined Luciola s. str.including 17 species previously listed under the subgenusLuciola in McDermott (1966).This definition allowed the erection of many new genera involving transfers of species from Luciola( Luciola)sensuMcDermott (1966).In their work,Ballantyne et al. (2019)recommended for transfer of seven species (including L. costata Pic) to the genus Curtos, assigned 33 species (including two synonyms) to Luciola s. lato and treated 35 species as species incertae sedis.Most recently, the status of the genus Luciola s. str.has been updated with erection of a new genus Nipponoluciola Ballantyne, Kawashima, Jusoh & Suzuki(Ballantyne et al. 2022).The new genus has been erected for two species of Japanese fireflies Nipponoluciola cruciata (Motschulsky) and Nipponoluciola owadai (Satô & Kimura) possessing aquatic larvae.They have also suggested for placements of many of remaining species listed under Luciola inBallantyne et al. (2019)and mentioned the problems in proper taxonomic arrangement of a few of these species, like misidentification of specimens, loss of holotypes, mislabelling, inadequacy of original descriptions, degradation of specimens in museums as an effect of longer course of preservation, larger cost of obtaining support from European museums, where most of the types are located and the difficulties imposed during Covid situation at global level from 2020(Ballantyne et al. 2022).The Indian checklist (Table1) presented in this work, reflecting only about 8% (33 out of 400) of the World Luciolinae firefly fauna, clearly shows the need for more taxonomic studies on this group to be carried out in the country.The listed species of the country exhibit about 33% endemism (11 out of 33 species endemic to India).The highest number of species was recorded from the State of West Bengal(11), followed by Tamilnadu (seven), Odisha (five), Karnataka and Maharashtra (four each), Assam (three) and Andaman and Nicobar Islands, Goa and Kerala (two each).Unfortunately, only a single species has been reported from Bihar, Madhya Pradesh, Meghalaya, Pondicherry and Sikkim.Out of the total species recorded in India, Abs.chinensis (from five States), Abs.perplexa (from four States), Asy.humeralis and Asy.ovalis (each from three States), Scl.aquatilis and Scl.substriata (each from three States), Abs.terminalis and Pt.malaccae (each from two States) could be considered as the prevalent firefly species of India.On the contrary, Py. insularis has been reported exclusively from Andaman and Nicobar Islands and Asy.circumdata from the Meghalaya State indicating a localised distribution.The distribution pattern of Indian species indicates that Abs.chinensis, Abs.perplexa, Abs.terminalis, Asy.humeralis, Asy.ovalis and Scl.aquatilis are the better studied and widely distributed species in India.However, for the rest of the species, either they are reported from only one/two States or their precise distribution in India is not known.Fu 2014, Ballantyne et al. 2019).Cambodia; Myanmar -Rangoon, Tharawaddy(Gorham 1895).Sri Lanka;Thailand; Vietnam  (McDermott 1966, Ballantyne et al. 2016, Wattanachaiyingcharoen et al. 2016, Wijekoon et al. 2016, Seri and Rahman 2021).Ballantyne et al. 2019).Cambodia(Ballantyne  et al. 2016, Seri andRahman 2021).SriLanka (Wijekoon et al. 2021).