GEHAN'S PHOTO GUIDE

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Matjaž Bedjaniè, Karen Conniff, Gehan de Silva Wijeyeratne

Jetwing

A Conservation Project

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A Photographic Guide to the Dragonflies of Sri Lanka

Matjaž BedjaničKaren Conniff

Gehan de Silva Wijeyeratne

Gehan’s Photo GuidesGehan’s Photo Guide series is published by Jetwing Eco Holidays, a standard setting wildlife travel company. Jetwing Eco Holidays would like to thank its Jetwing associates, industry counterparts, service suppliers and clients for their support to make it a force for conservation.

Wildlife populariser Gehan de Silva Wijeyeratne has enlisted the support of many individuals on a crusade to create a million, knowledgeable wildlife enthusiasts, by the year 2025. One of the primary objectives of the Photo Guide series is to enable a broad spectrum of people from school children to safari jeep drivers to other interested adults to be able to know a plant or animal by its name. This is an important and key step for creating awareness and hence support for conservation.

Everyone can contribute to conservation by something as simple as setting aside a few square feet in a back garden to run wild. This will create a habitat for native plants and animals. The Photo Guide Series will help people to put a name to what they see and appreciate the diversity of life.

First Edition: October 2007

First Print: October 2007

Published by: Jetwing Eco Holidays.

Citation: Bedjanič, M., Conniff, K., de Silva Wijeyeratne, G. (2007). Gehan’s Photo Guide. A Photographic Guide to the Dragonflies of Sri Lanka. Jetwing Eco Holidays: Colombo. ISBN 978-955-1079-15-4

© The intellectual rights of the authors and photographers are asserted.

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Contents

Foreword ..................................................... 4

Introduction to Dragonflies ................................ 6

Life Cycle & Ecology ........................................ 7

Dragonfly Conservation ...................................10

Morphology ..................................................11

Sri Lanka Odonate Checklist .............................15

Simple key to suborders and families

of adult dragonflies of Sri Lanka ......................19

Species Accounts ...........................................23

Dragonfly Glossary ....................................... 232

Dragonfly literature for Sri Lanka ..................... 234

Natural History Organisations .......................... 238

Useful Natural History books ........................... 240

The Authors & Photographers .......................... 243

Acknowledgements ...................................... 245

Notes ....................................................... 247

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Dragonflies are very interesting and diverse insects. They instantly attract attention with their amazing flight skills and beautiful colours. Dragonflies mostly occur in the vicinity of different fresh water habitats like rivers, streams, marshes, lakes and even small pools and rice fields. Most species are seen as solitary individuals or in pairs during mating, although a few species occasionally occur in swarms. Observing them might be difficult at first, but after some practice it becomes easier. Understanding the behavior of different dragonfly and damselfly species helps with finding and observing them; this comes with timing and practice. Be patient.

Dragonflies are aggressive predators in the larval form as well as the winged adult. Their habit of sallying out from a favourite perch to catch prey provides good opportunities for patient observation. Providing a few upright sticks in the garden or a small nicely vegetated pool is an easy way of attracting dragonflies. A slow approach with a pair of close focusing binoculars will offer excellent views. Photographing dragonflies in the early morning is best when they are bit sluggish. However, the sunniest and hottest part of the day is even better, since dragonflies are true sun fans. Note how individuals perch along the axis of a stem, offering the best angle for photography. The Anisopterans usually hold their wings horizontal, but as the sun warms them they will hold their wings up or turned forward, to reduce the effects of heating. And of course, despite their size, bright colours and strong

Foreword

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flight, these beautiful insects are completely harmless to humans – they don’t bite, sting and are not harmful in any way.

It is hoped that the photographic plates in this guide will help newcomers to natural history place a name on the dragonflies they see around them. This book is intended to be a layman’s guide to field identification. However, it does not cover all species of dragonflies recorded in Sri Lanka. Several species have not been seen in more than sixty years, some may even be extinct and lost forever, and several are in the process of being reclassified while others have not yet been photographed. Nevertheless, it is an important step forward. It is the first photographic guide book to the dragonflies of Sri Lanka in any language. Since many of the species in this guide are also found in India it is hoped that this book will have a wider application beyond Sri Lanka.

Present knowledge concerning biology, ecology and distribution of many less common species is still fragmentary. The information presented in this book is based on field work experience of the authors as well as on all published and unpublished information on dragonfly species occurring in Sri Lanka. Nevertheless, the status of some species is probably open to considerable revision.

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Introduction to Dragonflies

Dragonflies and DamselfliesWhat are loosely referred to as Dragonflies are in fact three suborders with two suborders present in Sri Lanka. Dragonflies are in the suborder (Anisoptera) and Damselflies are in the suborder (Zygoptera), both belonging to Odonata. The Odonata are one of the smaller orders of insects numbering around 6,000 species world-wide. This is an ancient order with fossil records dating back to the Permian era 230 – 280 million years ago.

Sri Lanka’s Dragonfly faunaSri Lanka has 117 species of dragonflies and damselflies of which an astonishing 53 are endemic. The high occurrence of endemics makes them an important group in the study of Sri Lankan biodiversity. This guide provides photos of 91 species of which 34 are endemic. This collection of photos is a major step forward in understanding dragonflies, their habitat and brings awareness to the fragile conditions necessary for their survival.

Little is known of this faunal group in Sri Lanka including basic data on life cycles and larvae. Some very interesting species found in recent years still await description and it is quite likely that many additional ones are yet to be recorded and described. The excitement of describing a new species is only dampened by the realization that the island may have lost species before science could catch up with them.

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Life Cycle & Ecology

Incomplete metamorphosis – the life cycle consisting of egg and several larval instars followed directly by the adult phase – is characteristic of dragonflies. Beautifully coloured adult winged insects, which can be met along rivers, streams, paddy fields, marshes, pools and lakes almost year round, represent only the shorter phase of their life cycle. They spend most of their lives hidden from human eyes as larvae in the water.

Larvae develop from eggs, which, depending on species, were laid by females in plant tissue or dropped freely into the water. The first larval instar is very small, but after several moults the larvae become proportionally larger. Larvae appear as rough bodied clumsy looking creatures with spidery legs and have very little in common with the beautiful winged adults. Both adults and larvae are voracious eaters and very successful predators. All dragonfly larvae have a modified lower lip, which is innocently folded beneath the head at rest but can grasp prey with lightning speed. They feed on smaller water insects, including mosquito larvae and occasionally even small fishes. Swollen wing pads of fully grown larva clearly declare that it is ready to emerge. It climbs out of the water and emerges from an unbearably tight larval casing; remarkably the teneral adult quickly expands its soft wings and flies away before even developing brighter colours. Initially, newly emerged, adults indulge in feeding and

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their attractive colouration develops only after several days. During the pre-reproductive period and while feeding, the adults are often encountered far from their breeding places.

Male dragonflies are usually found on or near water environments; besides feeding, their main occupation seems to be an active search for a mate. Females live away from water and are mostly seen on the water when they mate or lay eggs, otherwise, they dwell and feed at forest edges and clearings to avoid contact with the males.

FIGURE 1: The life cycle of a dragonfly: (1) mating, (2) egg-laying, (3-6) larval development, (7) last moulting – emergence, (8) adult insect. (Drawing: M. Bedjanič)

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Mating in dragonflies is something special and is definitely one of the most interesting acts in nature. It is interesting that male’s and female’s primary sexual organs, which are situated at the end of abdomen, are not in direct contact during mating. Underneath the second and third abdominal segment, the male has so called secondary genital organs where sperm is transferred from the abdomen tip. The female, still securely held by the male’s anal appendages, bends her abdomen and genitalia to the secondary genitalia of the male and the partners are joined. This beautiful heart-shaped figure is called a “wheel” or “copula”.

For additional relevant information regarding dragonfly biology and ecology the reader is referred to more comprehensive dragonfly publications such as CORBET (1999), de Fonseka (2000) and ORR (2003).

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Dragonflies are often addressed as “guardians of the watershed”. In nature they appear at two levels – they are the subjects of conservation concerns as endangered species and as indicators of wetland habitat quality. In different stages of their lives, dragonflies occur both in terrestrial and freshwater habitats and are sensitive to disturbances in both. While habitat selection of adult insects strongly depends on vegetation structure, their larvae develop in water and are critical in regard to water quality and aquatic habitat structure. Therefore, along with birds and amphibians, dragonflies can serve as one of the key bio-indicator groups, whose high species diversity clearly mirrors favourable conservation of the wider wetland ecosystems.

Although dragonflies are generally considered to have little economic significance, both larvae and adults are predators near the top of food chains in their ecosystems. Some species feed chiefly on mosquitoes and their larvae. Thus, in some regions, their potential for pest control in paddy fields is substantial.

In Sri Lanka, case studies of dragonflies are urgently required for additional baseline data on biology and ecology of selected species in order to facilitate even wider applied research, conservation measures and long-term monitoring schemes.

Dragonfly Conservation

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Morphology

Knowledge of dragonfly morphology, including many minute details, is absolutely essential to determine individual species. In this book an attempt has been made to reduce the technical side to an acceptable level. But first it will help to answer some basic questions about what type of dragonfly you might see; “Does it belong to Zygoptera or Anisoptera?”, “Is it a male or a female?”, “Is it an adult, a juvenile or teneral?” With this sorted out, the next step is a family ranking lottery. Try to remember main characteristics found in the “Key to the suborders and families” chapter. After some experience, a quick look will be all that is needed to successfully determine the family. The choice of photos in the book will become narrower and the final answer much easier.

Damselfly or dragonfly?As pointed out earlier, the dragonflies of Sri Lanka can be divided into two suborders – damselflies (Lat. Zygoptera) and dragonflies (Lat. Anisoptera). The broadly applied term “dragonflies” applies to both suborders.

Damselflies (Zygoptera) are generally small and delicate insects with hammer-shaped head on which the compound eyes are well separated, match-like slender abdomen and essentially equally shaped narrow wings (Fig. 2), which at rest are folded over abdomen or are slightly spread.

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Dragonflies (Anisoptera) are generally larger and more robustly built insects, in which large compound eyes cover almost the entire head. Their hindwings are always expanded at the base (Fig. 3), the venation of fore and hindwings differs substantially and at rest, the wings are broadly opened.

Apart from abdomen and wing length measurements given in the book, which can vary considerably and are only approximate, colour and markings can also vary depending on sex and age of the individual.

FIGURE 2: Wing morphology of a damselfly (Zygoptera, family Coenagrionidae).

FIGURE 3. Wing morphology of a dragonfly (Anisoptera, family Corduliidae).

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This is one of the reasons that scientific work and species determination is often based on stable minute structural characters, such as the shape of a female’s prothorax or the shape of anal appendages in males. For the purpose of this book and field observation guidance for the general naturalist this would be too complicated and a sound compromise is needed.

Male or a female?In dragonflies, mature males and females often look very different, the males regularly being more conspicuous and brightly coloured. However, freshly emerged and young males often resemble paler females in colouration. Wing venation and often patterns on the thorax are not sex dependant.

Since males are more common near water, the majority of individuals observed are likely to be males. Generally quite similar individuals will vary slightly in colouration; this may be age dependant and does not necessarily mean that there are two species in front of you.

But returning to the above question: males can be recognised by the secondary genitalia, which are distinctly protruding under the abdomen like a pinhead, best visible from the side (Fig.4). They also have differently shaped anal appendages at the abdomen tip which are used to hold a female’s head or neck during mating.

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Females’ abdomens in Zygoptera have thicker terminal ends due to distinct ovipositors; an organ below the abdomen tip, used to lay eggs in plant tissue. In Anisopteran families, because females lay eggs directly into the water they have reduced simple straight shaped ovipositors. Here, presence of two simple straight appendages at the abdomen tip might be useful in confirming their sex.

FIGURE 4. General morphology of an adult dragonfly (Anisoptera, family Gomphidae).

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Sri Lanka Odonate Checklist

Suborder Zygoptera - Damselflies Family Calopterygidae - JewelwingsOriental Green-wing (Neurobasis chinensis chinensis) Pg. 28Black-tipped Flashwing (Vestalis apicalis nigrescens) E Pg. 30

Family Chlorocyphidae - JewelsAdam’s Gem (Libellago adami) E Pg. 34Ultima Gem (Libellago finalis) E Pg. 36Green’s Gem (Libellago greeni) E Pg. 38Indian Yellow-lined Gem (Libellago lineata indica)

Family Euphaeidae - GossamerwingsShining Gossamerwing (Euphaea splendens) E Pg. 42

Family Lestidae - SpreadwingsScalloped Spreadwing (Lestes praemorsus decipiens) Pg. 46White-tipped Spreadwing (Lestes elatus) Pg. 48Malabar Spreadwing (Lestes malabaricus) Emerald Sri Lanka Spreadwing (Sinhalestes orientalis) E Metallic-backed Reedling (Indolestes divisus) E Mountain Reedling (Indolestes gracilis gracilis) E Pg. 50

Family Coenagrionidae - BluetsWhite-backed Wisp (Agriocnemis femina) Pg. 54Wandering Wisp (Agriocnemis pygmaea pygmaea) Pg. 56Sri Lanka Midget (Mortonagrion ceylonicum) E Pg. 58Marsh Dancer (Onychargia atrocyana) Pg. 60Malay Lilysquatter (Paracercion malayanum) Pg. 62Little Blue (Enallagma parvum) Asian Slim (Aciagrion occidentale) Dawn Bluetail (Ischnura aurora aurora) Pg. 64Common Bluetail (Ischnura senegalensis) Pg. 66Painted Waxtail (Ceriagrion cerinorubellum) Pg. 68Yellow Waxtail (Ceriagrion coromandelianum) Pg. 70Malabar Sprite (Pseudagrion malabaricum) Pg. 72

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Blue Sprite (Pseudagrion microcephalum) Pg. 74Azure Sprite (Pseudagrion decorum) Pg. 76Sri Lanka Orange-faced Sprite (Pseudagrion rubriceps ceylonicum) E Pg. 78

Family Platycnemididae - FeatherlegsYellow Featherleg (Copera marginipes) Pg. 82

Family Platystictidae - ForestdamselsAdam’s Shadowdamsel (Drepanosticta adami) E Austin’s Shadowdamsel (Drepanosticta austeni) E Brinck’s Shadowdamsel (Drepanosticta brincki) E Pg. 86Nobel Shadowdamsel (Drepanosticta digna) E Fraser’s Shadowdamsel (Drepanosticta fraseri) E Merry Shadowdamsel (Drepanosticta hilaris) E Drooping Shadowdamsel (Drepanosticta lankanensis) E Pg. 88Dark Knob-tipped Shadowdamsel (Drepanosticta montana) E Pg. 90Nietner’s Shadowdamsel (Drepanosticta nietneri) E Pg. 92Sinhalese Shadowdamsel (Drepanosticta sinhalensis) E Pg. 94Starmühlner’s Shadowdamsel (Drepanosticta starmuehlneri) E Bordered Knob-tipped Shadowdamsel (Drepanosticta submontana) E Blue-shouldered Cornuted Shadowdamsel (Drepanosticta subtropica) E Dark-shouldered Cornuted Shadowdamsel (Drepanosticta tropica) E Pg. 96Wall’s Shadowdamsel (Drepanosticta walli) E Dark Forestdamsel (Platysticta apicalis) E Pg. 98Blurry Forestdamsel (Platysticta maculata) E Pg. 100

Family Protoneuridae - ThreadtailsRamajana Bambootail (Disparoneura ramajana) E Two-spotted Threadtail (Elattoneura bigemmata) E Pg. 104Jungle Threadtail (Elattoneura caesia) E Pg. 106Dark-glittering Threadtail (Elattoneura centralis) E Pg. 108Smoky-winged Threadtail (Elattoneura leucostigma) E Red-striped Threadtail (Elattoneura tenax) E Pg. 110Stripe-headed Threadtail (Prodasineura sita) E Pg. 112

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Suborder Anisoptera - DragonfliesFamily Gomphidae - ClubtailsSolitaire Clubtail (Anisogomphus solitaris) E Sinuate Clubtail (Burmagomphus pyramidalis sinuatus) E Pg. 116Transvestite Clubtail (Cyclogomphus gynostylus) E Pg. 118Sri Lanka Sabretail (Megalogomphus ceylonicus) E Pg. 120Brook Hooktail (Paragomphus henryi) E Pg. 122Sri Lanka Grappletail (Heliogomphus ceylonicus) E Lyrate Grappletail (Heliogomphus lyratus) E Nietner’s Grappletail (Heliogomphus nietneri) E Wall’s Grappletail (Heliogomphus walli) E Pg. 124Keiser’s Forktail (Macrogomphus annulatus keiseri) E Sri Lanka Forktail (Macrogomphus lankanensis) E Pg. 126Wijaya’s Scissortail (Microgomphus wijaya) E Pg. 128Rivulet Tiger (Gomphidia pearsoni) E Pg. 130Rapacious Flangetail (Ictinogomphus rapax) Pg. 132

Family Aeshnidae - HawkersPale-spotted Emperor (Anax guttatus) Fiery Emperor (Anax immaculifrons) Pg. 136Elephant Emperor (Anax indicus) Pg. 138Vagrant Emperor (Anax ephippiger) Pg. 140Indian Duskhawker (Gynacantha dravida) Pg. 142Dark Hawker (Anaciaeschna donaldi) Pg. 144

Family Corduliidae - EmeraldsBlue-eyed Pondcruiser (Epophthalmia vittata cyanocephala) E Pg. 148Flint’s Cruiser (Macromia flinti) E Sri Lanka Cruiser (Macromia zeylanica) E Pg. 150

Family Libellulidae - ChasersFruhstorfer’s Junglewatcher (Hylaeothemis fruhstorferi fruhstorferi) E Pg. 154Yerbury’s Elf (Tetrathemis yerburyii) E Pg. 156Sombre Lieutenant (Brachydiplax sobrina) Pg. 158Pale-faced Forestskimmer (Cratilla lineata calverti) Pg. 160Pruinosed Bloodtail (Lathrecista asiatica asiatica) Pg. 162Spine-tufted Skimmer (Orthetrum chrysis) Pg. 164Asian Skimmer (Orthetrum glaucum) Pg. 166Marsh Skimmer (Orthetrum luzonicum) Pg. 168

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Pink Skimmer (Orthetrum pruinosum neglectum) Pg. 170Green Skimmer (Orthetrum sabina sabina) Pg. 172Triangle Skimmer (Orthetrum triangulare triangulare) Pg. 174Blue Pursuer (Potamarcha congener) Pg. 176Asian Pintail (Acisoma panorpoides panorpoides) Pg. 178Asian Groundling (Brachythemis contaminata) Pg. 180Indian Rockdweller (Bradinopyga geminata) Pg. 182Oriental Scarlet (Crocothemis servilia servilia) Pg. 184Black-tipped Percher (Diplacodes nebulosa) Pg. 186Blue Percher (Diplacodes trivialis) Pg. 188Light-tipped Demon (Indothemis carnatica) Pg. 190Restless Demon (Indothemis limbata sita) Pg. 192Paddyfield Parasol (Neurothemis intermedia intermedia) Pg. 194Pied Parasol (Neurothemis tullia tullia) Pg. 196Spine-legged Redbolt (Rhodothemis rufa) Pg. 198Red-veined Darter (Sympetrum fonscolombii) Pg. 200Crimson Dropwing (Trithemis aurora) Pg. 202Indigo Dropwing (Trithemis festiva) Pg. 204Dancing Dropwing (Trithemis pallidinervis) Pg. 206Aggressive Riverhawk (Onychothemis tonkinensis ceylanica) Pg. 208Asian Widow (Palpopleura sexmaculata sexmaculata) Pg. 210Sapphire Flutterer (Rhyothemis triangularis) Pg. 212Variegated Flutterer (Rhyothemis variegata variegata) Pg. 214Amber-winged Glider (Hydrobasileus croceus) Wandering Glider (Pantala flavescens) Pg. 216Burmeister’s Glider (Tramea basilaris burmeisteri) Pg. 218Sociable Glider (Tramea limbata) Pg. 220Foggy-winged Twister (Tholymis tillarga) Pg. 222Dingy Duskflyer (Zyxomma petiolatum) Pg. 224Elusive Adjutant (Aethriamanta brevipennis brevipennis) Pg. 226Coastal Pennant (Macrodiplax cora) Scarlet Basker (Urothemis signata signata) Pg. 228Sri Lanka Cascader (Zygonyx iris ceylonicum) E Pg. 230

Shaded lines indicate species that have not been included in this guide.E beside the species name indicates endemic species.

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Simple key to suborders and families of adult dragonflies of Sri Lanka

Key to SubordersSlender insects with eyes well separated by a space greater than their own diameter. Forewings and hindwings are essentially similar in shape and venation, narrow at base.

Robust insects with eyes usually touching broadly along the mid line, or if separated, never by a space greater than their own diameter. Hindwing expanded at base. Venation of forewing and hindwing very different.

Key to Families of Zygoptera1a Numerous antenodal crossveins

in the costal space of both wings. Wings often coloured, sometimes iridescent.

1b Only two antenodal crossveins in the costal space. Wings hyaline.

2a Very small stout species with abdomen shorter than hindwings. Front of head produced to form a projecting rostrum or “nose”; hindwings 15-30 mm.

2b Larger species, abdomen clearly longer than hindwings.

Zygoptera

Anisoptera

2

4

Chlorocyphidae(pp. 32)

3

20

3a Larger species with long-legs. Head, thorax and abdomen mostly bright metallic green. Hindwings 32-38mm.

3b Robust species with short legs and forewings longer than hindwings. Head, thorax and abdomen never metallic green. Hindwings 30-35mm.

4a Numerous supplementary veins inserted between the main veins from the distal wing margin to the level of pterostigma. Pterostigma large, narrow, distinctly longer than broad.

4b Supplementary veins absent from the wing tip, or if present, only to the depth of 1-2 cells only. Pterostigma only slightly longer than broad or diamond shaped.

5a Anal vein absent or very poorly developed, never extending beyond distal end of quadrilateral.

5b Anal vein well developed, extending

at least two cells beyond distal end of quadrilateral.

Calopterygidae(pp. 26)

Euphaeidae(pp. 40)

Lestidae(pp. 44)

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6

7

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6a Tip of wings not evenly rounded, slightly angulated. Brown or black coloured damselflies with azure blue markings on abdomen.

6b Tip of wings evenly rounded. Totally or partly black with orange, yellowish or whitish markings, never with azure blue markings on abdomen.

7a Head narrow, striped, length to width ratio more than 1:4. Femora and tibiae with many spines. Never with blue or green markings.

7b Head broad, length to width ratio approximately 1:3. Often with blue or green markings.

Key to Families of Anisoptera1a Eyes clearly separated. Makes

flights from a perch, without flying continuously for long periods.

1b Eyes broadly contiguous or at least

touching.

Platystictidae(pp. 84)

Protoneuridae(pp. 102)

Platycnemididae(pp. 80)

Coenagrionidae(pp. 52)

Gomphidae(pp. 114)

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2a Triangles similarly oriented in both wings, with sharp angles pointing to the wing tips. Females with well-developed ovipositor. Never metallic, often at least partly blue or green coloured. Large species, constant fliers.

2b Triangles differently oriented, with sharp angles pointing to the abdomen tip in the forewing and to the wingtips in hindwing. Females lacking ovipositor.

3a Posterior eye margin with prominent bulge. Thorax and abdomen often dark metallic green with yellowish markings, never predominantly yellowish, brown, red or blue. Constant tireless fliers.

3b Posterior eye margin without prominent bulge. Thorax and abdomen only very rarely metallic. Predominantly yellowish, brown, red or blue coloured, abdomen often priunosed in males. Makes flights from a perch without flying continuously for long periods.

Aeshnidae(pp. 134)

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Corduliidae(pp. 146)

Libellulidae(pp. 152)

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Species Accounts

All species accounts are similarly structured and explained in the following paragraphs.

Name Common names in English, Sinhala and Tamil langauges are used for convenience but common names may not be the same between Sri Lanka and India or other locations in Asia. To avoid possible confusion the scientific name is also used. The scientific name can help overcome the variation in common names.

Male Usually more obvious due to position on or near water and due to colouration. A brief field description is given to help confirm the sighting of certain species. Some specific identification features will be included in an insert to clarify further.

Female Can be similar to the male or quite different depending on the species and age of the female. Because females are encountered less often and are more difficult to photograph they are not always included on the following pages. A brief description will be given for most females unless the female is still not described or has yet to be found.

Measure line The line shown is only a rough indication of the approximate natural length of the species in the photographs.