The Dragonflies of Sri Lanka The Dragonflies of Sri Lanka By Terence de Fonseka ^jSfe^ WHT THE DRAGONFLIES OF SRI LANKA By Terence de Fonseka © 2000 Terence de Fonseka Published by WHT Publications (Private) Limited, 95 Cotta Road, Colombo 8, Sri Lanka. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the written permission of the publisher. Set hi Palatino. Cover design suggested by Joanna Elizabeth Cover pictures by Matjaz Bedjanic Colour separation and typeset by Ms Colour Graphics Limited, Colombo, Sri Lanka. Printed by Gunaratne Offset Limited, Colombo, Sri Lanka. ISBN 955-9114-19-0 Front cover: Trithemis aurora Back cover top: Pantala. flavescens; bottom: Diplacodes trivialis. CONTENTS Foreword 7 Systematic list of Sri Lankan species 11 Notes 15 General 17 Figure series A (Al-24) 27 Key to Sri Lankan species 31 Zygoptera— Calopterygidae 32 Euphaeidae 35 Chlorocyphidae 38 Lestoidea and Coenagrionoidea 45 Lestidae 46 Platycnemididae 53 PlatystLctidae 55 Protoneuridae 71 Coenagrionidae 79 Anisoptera— Gomphidae 103 Aeshnidae 125 Corduliidae 133 Libellulidae 140 Figure series B (Bl-129) 202 Key to larvae 220 Figure series C (Cl-69) 260 Rearing larvae 281 Making and keeping a collection 282 List of species in the Colombo Museum collection 283 Glossary 285 Literature cited ' 289 Postscript 296 Index 297 FOREWORD I have had two main aims in writing this account of the dragonflies of Sri Lanka. The first and I now consider this to be of lesser importance, was to bring together what little is known about them and so provide a reference book or guide for those who may choose to be interested in this moderately attractive Order of insects. But then it became clear to me that making such information available would not of itself lead to an interest in the group. There are two reasons for this. The first, and a trivial one at that, is that the dragonflies, and more so the damselflies, are not for the most part spectacular in their appearance and though fairly common, they are not seen and noticed unless they are being looked for. The second and what I considered a more important reason when I started on this work was that there did not then appear to be any compelling interest in Sri Lanka in the practical study of natural history; leaving aside the smaller, less conspicuous animals, not even in the butterflies, the birds and other vertebrates. There has been a demand for the publications on these groups, but I suspect this has been more for their rarity value in terms of money than for their scientific content. I believe the situation has changed, considerably I hope, since the re- publication of many of the earlier books on Sri Lankan natural history and the new publications on such subjects sponsored by WHT Publications. Hence, what has assumed the greater importance in what I am putting together. I am doing this primarily for the younger people in the country. This emphasis in direction has been brought about by what I have seen while living in Britain for the last several years. There is a great interest in science among the young. A considerable part of that interest is in natural history. This is created in the schools to a great degree by visits to the museums and by the projects which the-children are required to study up and write. Additionally, there are some excellent television programmes on natural history that serve to evoke and nurture an interest in that area. I myself started to work on the Sri Lankan dragonflies a few years before I left the country. It was only after I came to Britain that I realised the handicaps under which I had been trying to work There is practically no recent literature, and what there is, is in the Museum library. I had easy access to that library and I expect so will others who want to use it. Problems of time and travel do however exist for those who want to take up the study of this group while in school or in full time employment: access to the library will be more difficult for those outside Colombo. I hope this work will make matters easier for all. I have relied on the works of the many authors included in the list of references. I have tried to verify the descriptions and to include a few figures of my own where it has been possible to do so. I have written, I hope, with scientific accuracy at a modest technical level. It is my aim to acquaint readers with this interesting group of insects and to show them that there is much to intrigue them in the study of the group both in the adult and in the larval stages and in their life histories; to make them aware of the group, many members of which can be seen in their own gardens, even in urban areas; a few even entering their homes in the late evenings, either attracted to the lights or following other insects that are so attracted. In urban areas there still may be patches of water where the adults can be observed and if necessary captured for study and identification. These same stretches of water will be the homes of the larvae, many of which can be found in very shallow water, and collected with a home made "dredge" and reared, generally with very little difficulty, until the imago emerges, providing a means of identifying each larva with its final adult. Such identification is not yet available for many of the Sri Lankan species. And here is the encouraging possibility for the enthusiastic worker to write a paper that will almost certainly be accepted for publication by one or another of the scientific journals dealing with this Order in particular or with insects in general. There will be no attempt to avoid technical terms, which will be used as the need arises; either they will be explained fully at the first time of use or be listed in the glossary. It is necessary to point out that this document deals with the identification and distribution within Sri Lanka of the species found here. Attention is drawn to the need to know more about the life histories and larval stages of these species, which together with behaviour and physiology get greater emphasis today than does systematics, and even in systematics the importance of cytology is growing. Some of these aspects are properly for the academic zoologist or entomologist, but life history, larvae and behaviour are well within the scope of the amateur naturalist. There is a British Dragonfly Society in Britain. Its members, mostly amateur naturalists, are engaged in the study of British dragonflies in then- native environment and contribute to the regularly published journal of the Society. Many similar societies exist in other countries and there is one in India. I hope this work will lead to the formation of one in Sri Lanka. I must emphasise that there is very little original work here, but I hope that bringing together the available information on the Sri Lankan dragonflies will prove useful. I must acknowledge my indebtedness to the several authors listed, though some of their work has not been directly available to me. I must mention specially Fraser on whose work I have drawn extensively, Kirby, Lieftinck and Laidlaw: these authors have worked and written much on Sri Lankan dragonflies; Fraser's three volumes on the Odonata have been the major source of information and I must thank Taylor & Francis, the original publishers and the Today & Tomorrow Publishers of New Delhi, who have republished the three volumes recently, for their agreement that I could draw extensively from this work. I am indebted to Arun Kumar's work on the larvae of Indian dragonflies that has provided me with much of the information and many of the figures for the section on larvae. I have also to acknowledge the assistance given by the Director of the Colombo Museum, Dr (Mrs) Thelma Goonewardene since retired, the Museum's Curator in Entomology, Lakshman Weeratunge, Dr. Priyantha Wijesinghe of New York who encouraged, criticised and provided most of the information on the early study of dragonflies in Sri Lanka and Matjaz Bedjanig of Slovenia whose criticism of my drafts has corrected many errors. Any remaining errors are mine. Dr Matti Hamalainen of Finland has helped to identify the specimens on some of the colour photocopies. I have also to record my indebtedness to those who provided me with the colour slides from which the colour plates in the Guide have been made. They are C. A. and P.M. Allen, Matzaz Bedjanic, Harms-Dieter Mitzka and Marion Monig, and Lakshman Weeratunga. They are named in the List of Plates. I must make special mention of Rohan Pethiyagoda of WHT Publications of Sri Lanka whose insistence on revisions has made a book out of my draft. Finally, it is necessary to draw attention to the danger to the Island's fauna (and flora) caused by the clearing of large extents of jungle and the filling up of lowlands for development. Some larger forests are protected now, but many smaller areas are disappearing or their supplies of water are diverted and no longer available. There is an environmental protection agency and I hope it will extend its protection to the smaller areas also. Additionally, the Island appears to be having an influx of collectors, posing as bona fide tourists, collecting and taking away with them, insects and other small animals for sale abroad.