Odonata larvae of Keibul Lamjao National Park , Manipur , northeastern India

Acknowledgements: The authors are thankful to the Head, Dept. of Ecology & Environmental Science, Assam University, Silchar, Assam for providing laboratory facilities. The first author is also thankful to University Grants Commission, New Delhi, India for financial support. The Keibul Lamjao National Park (KLNP) situated in the state of Manipur, northeastern India, is the only floating park in the world and noted as the last refuge of the Sangai Rucervus eldii eldii. It is an integral part of Loktak Lake formed by phumdis with an area of 40km2. Phumdis, are a heterogeneous mass of soil, vegetation and organic matter at various stages of decomposition floating on lake water. Odonata larvae have exploited a wide range of permanent and temporary aquatic habitats including brackish pools and estuarine habitats. In recent years all known Odonata species from the Japanese Archipelago were published by Okudaira et al. (2005). In Malaysia, Indonesia, Singapore and Brunei ca. 700 species occur in the region of which ca. 500 are endemic (Orr 2004). Fraser (1933–1936) published three volumes on Odonata in the ‘Fauna of British India’ including 536 species and Abstract: Odonata larvae were collected from Keibul Lamjao National Park, Manipur, northeastern India during 2009–2011. The study recorded 15 species of Odonata larvae belonging to the anisopteran families Aeshnidae, Libellulidae and zygopteran families Calopterigidae, Lestidae and Coenagrionidae. The study revealed that there is a need for a detailed study of Odonata fauna of the national park as thorough knowledge of the important species of a conservation area is very essential for proper management.

The Keibul Lamjao National Park (KLNP) situated in the state of Manipur, northeastern India, is the only floating park in the world and noted as the last refuge of the Sangai Rucervus eldii eldii.It is an integral part of Loktak Lake formed by phumdis with an area of 40km 2 .Phumdis, are a heterogeneous mass of soil, vegetation and organic matter at various stages of decomposition floating on lake water.
Odonata larvae have exploited a wide range of permanent and temporary aquatic habitats including brackish pools and estuarine habitats.In recent years all known Odonata species from the Japanese Archipelago were published by Okudaira et al. (2005).In Malaysia, Indonesia, Singapore and Brunei ca.700 species occur in the region of which ca. 500 are endemic (Orr 2004). Fraser (1933-1936) published three volumes on Odonata in the 'Fauna of British India' including 536 species and subspecies of Odonata from India with many species from Bangladesh, Bhutan, Myanmar, Nepal, Pakistan and Sri Lanka.According to Subramanian (2009), in India there are 463 species/subspecies belonging to 140 genera.Some taxonomic studies on larvae have been done in India, such as Needhams (1911).Prasad & Varshney (1995) published a checklist of the Indian odonates, including updated data on larval studies of all known species.This paper presents a list of different species of Odonata larvae collected from Keibul Lamjao National Park.

MATERIALS AND METHODS
The Odonata larvae were collected from water with a dip net (mesh size -60µm) from various places of Keibul Lamjao National Park using the 'kick sampling' method and by dragging the net around the vegetation for three minutes (Macan & Maudsley 1968;Brittain 1974;Subramanian & Sivaramakrishnan 2007).
To ensure a representative sample of the odonate fauna, a monthly collection was undertaken from 2009 until 2011.Collected Odonata larvae were immediately sorted and preserved in 70% ethyl alcohol.They were later identified using a Dewinter advance stereozoom microscope with the help of standard keys (Kumar 1973a, b;Westfall & Tennessen 1996;Srivastava & Sinha 5859 2004).

RESULTS AND DISCUSSION
A total of 15 species of Odonata larvae belonging to 15 genera, five families and two suborders were recorded (Table 1).The Odonata larvae recorded from the park are shown with their systematic position in the Table 1 and Image 1. 1) Crocothemis servilia servilia (Drury): Absence of mid dorsal abdominal spines.Premental setae 14+14.Palpal setae 10 &10 2) Sympetrum sp.: Presence of mid-dorsal abdominal spines.Superior abdominal appendage much shorter than inferiors.Lateral spines of abdomen short, not reaching tips of anal appendages.
3) Rhodothemis sp.: Mid-dorsal abdominal spines are absent.Lateral spine on abdominal segment 9 only.Lateral spine short, length less than half the mid-dorsal length of segment 9. Premental setae 12+12; palpal setae 8+8.dorsal abdominal spines.Eyes tend to point upwards; eye tending to round.Lateral spines on abdominal segments 8-9, spines on segment 9 small, not longer than middorsal length, spines on segment 8 small, at least shorter than middorsal length.7) Urothemis sp.: Eyes extended to posterior corners of head, pointed.Lateral spines on abdominal segments 8-9, spines on segment 9 substantial as long as the middorsal length, spines on segment 8 at least shorter than middorsal length.
8) Leucorrhinia sp.: The eyes generally make up about half the length of the head.Superior abdominal appendage about as long as the inferiors.Length of the lateral spine of segment 9 less than the mid-dorsal length of segment 9. 9) Anax sp.: Abdomen with lateral spines on segments 7 to 9. Superior anal appendage but slightly shorter than inferiors.Inferiors about one and one-half times as long as mid-dorsal length of segments 9 and 10. 10) Aeshna juncea (Mongolica): Abdomen with lateral spines on segments 6 to 9. Lateral anal appendages greater than one-half the length of the inferiors.Palpal lobes >1.50x as wide as the movable hook at its basal articulation, the distal margin squarely truncate and the outer distal angle a little rounded.
11) Neurobasis chinensis chinensis (Linnaeus): Large caudal lamellae, epiproct and paraproct in the form of large, elongated lamellae.Major premental and palpal setae absent.Prementum widely bifurcated in the middle.Laterally the distal ends project into long thin processes.One small spiniform setae present at about the middle of each of these processes.