Dragonflies and Damselflies (Insecta: Odonata) of Aryanad Grama Panchayat, Kerala, India

: A year-long study to document the diversity and seasonality of odonates was conducted at Aryanad Grama Panchayat, Thiruvananthapuram district, Kerala, southern India. A total of 93 species (56 dragonflies and 37 damselflies) belonging to 12 families were recorded. Twenty-four species of odonates recorded are endemic to the Western Ghats, three to peninsular India and one to India. Small streams showed the highest species richness, hosting 69 species and ponds the lowest with 59 species. Species richness showed a peak during the southwest monsoon season and a dip in winter. The study highlights the importance of biodiversity documentation at regional level.


INTRODUCTION
Protected areas are the cornerstones of global biodiversity conservation efforts. India has established a network of protected areas covering approximately 4.8% of its geographical area, but it is impossible to bring the entire range of biodiversity under this network (Mathur & Sinha 2008). It is therefore, imperative that we take measures to document and conserve biodiversity outside protected areas. Under the Biological Diversity Act of 2002, the Grama Panchayats in India are mandated to form Biodiversity Management Committees (BMCs) for the documentation, conservation and sustainable use of bioresources. Kerala is the first state in India to form BMCs in all its local bodies (Kerala State Biodiversity Board 2021). However, the documentation of insect biodiversity is incomplete in most of the People's Biodiversity Registers (PBRs) prepared by the BMCs.
Dragonflies and damselflies, which together form the insect Order Odonata are considered as important components of freshwater ecosystems as well as good indicators of ecosystem health because of their amphibious life history, relatively short generation time, high trophic position and diversity (Corbet 1993;Clark & Samways 1996). Biodiversity of insects is threatened worldwide (Sánchez-Bayo & Wyckhuys 2019) and one in 10 species of dragonflies and damselflies is threatened with extinction (Clausnitzer et al. 2009). This global decline of insect populations is feared to cause a catastrophic collapse of earth's ecosystems (May 2010). The endemic species of odonates have a narrow distribution across the Western Ghats, occurring in only small patches of suitable habitats (Subramanian et al. 2011;Koparde et al. 2014). .224 0 E) is an agricultural village under the foothills of Agasthyamalai of southern Western Ghats in Thiruvananthapuram district, Kerala (Figure 1). The predominant crops grown here are coconut, rubber, banana, and vegetables (Government of Kerala 2021). Aryanad lies adjacent to the Peppara Wildlife Sanctuary and the Karamana River that originates in the Western Ghats flows through the village.

MATERIALS AND METHODS
Four ponds (with area less than 30 m 2 ), three small streams (with width approximately 0.5 m), five large streams (with width approximately 2 m) and the Karamana River having a width of approximately 6 m were selected in Aryanad Grama Panchayat for sampling odonates (Image 1). Each habitat was visited once every month from 1 December 2019 to 30 November 2020. Visual encounter surveys (VES) were done to document the odonates, where the observer walked along the edge of each waterbody for 20 minutes and recorded all the odonate species encountered. All the field visits were made between 0900 h and 1100 h. The odonates were photographed using a Nikon Z6 mirror-less camera and Nikon 105 mm macro lens. The individual odonates were identified to the species level referring to taxonomic monographs (Fraser 1933(Fraser , 1934(Fraser , 1936 and field guides (Subramanian 2005(Subramanian , 2009Kiran & Raju 2013). A checklist was prepared using systematic arrangement and taxonomy according to Kalkman et al. 2020. The study period was divided into four seasons for data analysis-winter (December-February), summer (March-May), south-west monsoon (June-August), and north-east monsoon (September-November).

RESULTS AND DISCUSSION
A total of 93 species of odonates (56 dragonflies and 37 damselflies) from 12 families were recorded from Aryanad Grama Panchayat (Table 1, Images 2-6). This accounts for more than half (53%) of the odonate species recorded from the state of Kerala till date (Society for Odonate Studies 2021). In comparable studies, only 82 species of odonates were recorded from Thattekkad Bird Sanctuary (Varghese et al. 2014) and 48 from Chinnar Wildlife Sanctuary (Adarsh et al. 2015). The high odonate diversity documented from Aryanad Grama Panchayat is probably due to the diverse habitats it sustains and its proximity to forests including those of Peppara Wildlife Sanctuary. Out of the 93 species recorded from Aryanad, 24 are endemic to the Western Ghats, three to Peninsular India and one to India. Small streams had the highest species count and ponds the least ( Figure 2). The species richness showed a peak during the south-west monsoon when 90 species were recorded and a dip in winter, when only 30 species could be seen ( Figure 3).
The records of the following species are significant considering their endemicity, rarity and threat status (Subramanian et al. 2018;IUCN 2021):

Protosticta sanguinostigma Fraser, 1922
This species, easily identified by the reddish brown equatorial band in its eyes and the peculiar shape of anal appendages is categorized as 'Vulnerable' by the International Union for Conservation of Nature and Natural Resources (IUCN) in its Red List of Threatened Species. It was recorded only from the lotic habitats of Aryanad and was unrecorded during winter. (Fraser, 1924) This small damselfly brightly coloured with sky blue, black and vermilion is the only extant species of the genus. It is endemic to the southern Western Ghats and has so far been recorded only from a few locations in Kerala and Karnataka. It was recorded from all three lotic habitat types of Aryanad Grama Panchayat and was sighted in all the seasons. An extensive search of literature and websites failed to produce even a single photograph of the female of this species. Hence, this is most probably the first photographic record of the female from the wild (Image 7). It remains a 'Data Deficient' species in the IUCN Red List.

Calocypha laidlawi
Elattoneura souteri (Fraser, 1924) This damselfly coloured brightly with red and black is a 'Data Deficient' species in the IUCN Red List and has so far been recorded only from a few locations in Kerala and Karnataka. It was recorded from all three lotic habitat types of Aryanad and could not be seen in winter.

Esme longistyla Fraser, 1931
This species was identified referring to characters like complete anal bridge vein, blue annules on abdomen, blue stripes on legs and structure of anal appendages. Even though it is classified as a 'Least Concern' species in the IUCN Red List, only very scarce reports of this species exist from Kerala and Karnataka. In Aryanad, it was recorded from both small and large streams. It could not be seen in winter.

Melanoneura bilineata Fraser, 1922
This rare and relatively large damselfly species is the sole representative of the genus and has so far been recorded only from a few locations in Kerala and Karnataka. It is coloured blue and black and can be distinguished by the absence of the anal bridge vein in its wings. This species, classified as 'Near Threatened' in the IUCN Red List was recorded from Aryanad in all four seasons. It could be seen only in the small streams and hence appears to show high habitat specificity.

Burmagomphus laidlawi Fraser, 1924
This medium-sized clubtail dragonfly has till now been recorded only from montane forest streams of Kerala, Karnataka and Tamil Nadu. It can be easily separated from other clubtail species by the structure of its anal appendages. It was recorded only during the southwest monsoon season and could be seen only in large streams. Hence, this species is highly seasonal and has specific habitat requirements. It remains a 'Data Nychogomphus striatus (Fraser, 1924) This medium-sized clubtail dragonfly has very few previous records from Kerala and Tamil Nadu. The record from Nepal requires validation. It has peculiar claw-shaped anal appendages that help to distinguish it easily from other clubtail species. It is a 'Data Deficient' species in the IUCN Red List and was recorded from all four habitat types sampled in Aryanad. It could be seen in both southwest monsoon and northeast monsoon seasons.

Epophthalmia frontalis Selys, 1871
Fraser (1924) described Macromia binocellata based on a single male specimen collected by C.M. Inglis from Palni hills, Western Ghats. Subsequently, more specimens were obtained from Tamaracherry, Calicut and Walayar in the Western Ghats after which he treated it as Epophthalmia frontalis malabarensis (Fraser 1935) and later, as Epophthalmia frontalis binocellata (Fraser 1936). According to the last source, within Indian limits, E. frontalis frontalis occurs in Assam and E. frontalis binocellata is confined to the Western Ghats. The taxon in the Western Ghats is described as a much darker insect compared to its congenerics. Its abdominal segments 4 to 6 have paired isolated sub-basal spots instead of rings. Also, its inferior anal appendage is distinctly longer and curves up between the apices of superiors. According to Lieftinck (1931) and Fraser (1936) E. frontalis and E. vittata can be separated from each other based on their facial markings, but Asahina (1987) disagrees and states that these markings vary depending on maturity and individuals. A large Macromiid was seen in the large streams and Karamana River in Aryanad, but its markings seem to match more with E. frontalis frontalis as described by Fraser (1936) and Asahina (1987). Its terminal abdominal segments, including the anal appendages were predominantly yellow. The inferior anal appendage was longer than the superiors whose apices it covered by curving in. A comparative analysis using the available resources and photographs lets us place the taxon encountered as Epophthalmia frontalis (Image 8), but taxonomic resolution beyond this level was impossible without examining specimens. Tiple & Payra (2020) (Fraser, 1924 Epophthalmia species, particularly E. frontalis and E. vittata. Another large Macromiid with its superior and inferior anal appendages of almost the same length was identified as E. vittata. Its last segments including the anal appendages were reddish brown with restricted yellow markings (Image 9). species richness during the southwest monsoon season was expected because most odonate species in India are known to emerge and breed during the monsoon (Subramanian 2005). Odonate diversity dips in winter coinciding with a fall in water level in their habitats and picks up in summer with the pre-monsoon showers. The small streams support the highest number of species probably because they have different microhabitats in the form of pools, marshes and slow flowing stretches. Aryanad village, with its plantations, home gardens and forests at the fringes probably functions as an ecotone, hosting rich biodiversity. Ecotones are ecological