Dragonflies and damselflies are extremely beautiful insects which capture the very essence of summer as they perform their intricate aerobatics around the gleaming backdrop of rivers and pools on warm and sunny days. As such they are highly visible, and important indicators of the health of our wetlands.
The 39 species of Odonata resident in Britain are divided into two sub-orders, the Zygoptera (damselflies) with 10 breeding species present in Cornwall, and the Anisoptera (dragonflies) of which there are 12 breeding species occurring in Cornwall. Over the last fifty years two species have probably become extinct within Cornwall, the Southern Damselfly - Coenagrion mercuriale, and the Orange-spotted Emerald - Oxygastra curtsii. Since 1995 C. mercuriale has been discovered at three north Dartmoor sites leading to renewed optimism that the species will be found in similar habitat on Bodmin Moor.
Populations of resident species are frequently reinforced by migrants from Europe, sometimes reaching our shores with spectacular non-resident species such as the Scarlet Darter - Crocothemis erythraea, the Yellow Winged Darter - Sympetrum flaveolum, and the Vagrant Emperor - Anax ephippiger. The most unexpected arrival to these shores must surely have been the Green Darner - Anax junius which arrived on the tail of Hurricane Earl in September 1998. In recent years only two migrant species have been recorded on a regular basis on the Cornish peninsula, the Red-veined Darter - Sympetrum fonscolombei now reasonably well established on the Lizard as a semi regular breeder, and the Lesser Emperor - Anax parthenope which has gone from being unknown in Britain to become a regular sighting since 1996, particularly in east Cornwall.
Without doubt the legacies of Cornwall’s once extensive mining industry have been a major source of prime dragonfly habitat. With very few exceptions, the sites which sustain the greatest diversity of species have been shaped by the search for tin or china clay, including areas such as the Red River Valley near Camborne, the Carnon Valley near Bissoe & Devoran and the St. Austell China Clay area/mid-Cornwall moors. The nationally scarce Scarce Blue-tailed Damselfly - Ischnura pumilio has benefited enormously from the slow rate at which natural vegetation recolonizes such sites. Another nationally scarce insect the Small Red Damselfly - Ceriagrion tenellum also flourishes at these sites where boggy pools have developed. One of Cornwall’s more elusive dragonflies, the Black-tailed Skimmer - Orthetrum cancellatum is another species which relies heavily on old mining sites such as the shallow serpentine quarries of the Lizard peninsula and the china clay workings of the St. Austell area.
To the east of the county the bogs and pools of Bodmin Moor are Cornwall’s most important areas of ‘natural’ wetland habitat for dragonflies and support the majority of sites for the Black Darter - Sympetrum danae, an insect completely absent from west Cornwall. The White-legged Damselfly - Platycnemis pennipes and the Banded Demoiselle - Calopteryx splendens are both uncommon in Cornwall and seem to be restricted to the River Tamar and its tributaries.
Recording in Cornwall
During the period 1988 to 1992 the national Odonata Recording Scheme organised a ‘Key Sites Project’. The aims of the project were to survey known and potential key breeding localities for dragonflies, establishing a national database for future monitoring of these important sites. In Cornwall a ‘key site’ is one which supports a breeding population of one or more of the following: Ischnura pumilio, Ceriagrion tenellum, and the Ruddy Darter - Sympetrum sanguineum (the presence of the Keeled Skimmer - Orthetrum coerulescens may also help to substantiate a site’s status). The Cornwall Dragonfly Group, a focus for local British Dragonfly Society members, was successful in surveying and confirming 63 such sites within Cornwall (Jones 1993). The presence of a population of Platycnemis pennipes along a water course indicated which of the county’s rivers could be considered Key Sites.
From 1992 to 2000 the recording scheme continued to be well supported in Cornwall with over 2650 records being submitted from the 1998 season alone, a success which reflects a policy of gladly taking records from everywhere and anywhere in the county regardless of the species involved. However, the main emphasis of recording within the county was to build up a reliable database of site-based information. This included a detailed site description and habitat map for as many localities as possible which when added to the ongoing species records (with the emphasis on evidence of breeding), stored on our Darter software (Biobase for Dragonflies), formed a very useful conservation document.
From 2000 to 2007 dragonfly recording in Cornwall broadly declined, however in the Spring of 2008 the Dragonflies in Focus Project, and recording for the National Dragonfly Atlas was launched by the British Dragonfly Society at the Natural History Museum in London. The aim of the project is to update the known distribution of British dragonfly and damselfly species over the next 5 years, culminating in the publication of a new national atlas in 2013. All records submitted to the county recorder in Cornwall will be fed into this project. The last national atlas was published back in 1996, and given the huge changes in climate & the environment that have taken place over the last decade or so, a new one is urgently required. This is a very important and worthwhile initative and your support will be very much welcomed.
With a little care and effort most species are readily identifiable in their adult form. However, these highly manoeuvrable insects can be difficult to approach so close focusing binoculars and/or a net are sometimes needed to obtain critical views.
Dragonfly watching need not be confined to fine weather, the study of larvae and exuviae (the cast skins of larvae emerging as adults), provide conclusive proof of which species are breeding at a site, and can be searched for in virtually any weather conditions. Although some larvae/exuviae are extremely difficult to identify, others are surprisingly easy with the aid of a x10 hand lens, or even the naked eye. Collecting the abandoned exuviae can give a good indication of the size of a population at a site, and may give the only clue to the presence of a species.
Submitting Records
The Cornish recording scheme is in effect the local arm of the national scheme so all accepted records will find their way into the Dragonfly Recording Network and the Migrant Dragonfly Project databases run by the British Dragonfly Society.
A printable version of the RA831 recording card and instructions on how to fill them in are available on the BDS website at http://www.dragonflysoc.org.uk/dragonfliesinfocus.html
However, all records are welcome, in whatever form they are submitted. The minimum amount of information required to provide a useful record is a six-figure grid reference, the name of the site, the date, and the species seen. Additional information such as any evidence of breeding, altitude, and habitat detail would greatly enhance the value of the record. Records from sites supporting the county’s key species would be particularly appreciated.
Cornish records for any species that is not currently known from the county (as well as the rarer ones that are), should be accompanied by conclusive proof of identification. Such proof can take the form of a specimen, a clear photograph, and/or a detailed description. Recorders should take note that some records, particularly of immigrant species will need to go before the national Odonata Records Committee if they are to be accepted.
Collecting voucher specimens has been a controversial subject in the recent past as entomologists are joined in their chosen interest by enthusiasts from other disciplines. The British Dragonfly Society has produced a code of conduct for collecting with conservation being very much the driving force, but one which also recognises the essential role which voucher specimens have in some circumstances. Given that exuviae are merely cast skins, not living beings, they do not fall within the remit of such codes of conduct.
Further Reading
For many years Hammond (1983) was the standard work for the identification of both adults and larvae. However, the publication by Brooks (1997) set a new standard for the illustration of adults, including recent additions to the British list. This, combined with its compact size make it the best choice in the field. A good general introduction to dragonflies can be found in Miller (1987), while Merritt et al. (1996) is an invaluable reference work with 10-km square distribution maps and analyses for all British species. There is now an excellent photographic guide to identifying dragonfly larvae/exuviae by Cham (2007). This very accessible publication allows all British species to be reliably identified with a little care. For those seeking a highly detailed account of the behaviour and ecology of Odonata, Corbet (1999) contains an incredible amount of information which is thoroughly cross referenced for ease of use. Other useful references are Askew (1988), Corbet (1962; reprinted 1983), and Corbet, Longfield & Moore (1960).
Checklist of Odonata found in Cornwall
British status Cornish status
Calopteryx virgo – Beautiful Demoiselle Common in the west Common
Calopteryx splendens – Banded Demoiselle Common in the south Locally Common/Scarce
Lestes sponsa – Emerald Damselfly Widespread/Local Locally Common
Plactynemis pennipes – White-legged Damselfly Nationally Scarce Locally Common/Scarce
Pyrrhosoma nymphula – Large Red Damselfly Common Common
Ischnura elegans – Blue-tailed Damselfly Common Common
Ischnura pumilio – Scarce Blue-tailed Damselfly Scarce Scarce
Enallagma cyathigerum – Common Blue Damselfly Common Common
Coenagrion mercuriale – Southern Damselfly Rare Extinct?
Coenagrion puella – Azure Damselfly Common Common
Ceriagrion tenellum – Small Red Damselfly Scarce Local
Aeshna juncea – Common Hawker Widespread/local in the north & west Widespread/local
Aeshna cyanea – Southern Hawker Common in the south Common
Aeshna mixta – Migrant Hawker Common in the southeast Local/expanding
Anax imperator – Emperor Dragonfly Widespread in the south Widespread
Anax junius – Common Green Darner Very rare immigrant Very rare immigrant
Anax parthenope – Lesser Emperor Scarce immigrant Immigrant/Scarce resident?
Anax ephippiger – Vagrant Emperor Scarce immigrant Rare immigrant
Cordulegaster boltonii – Golden-ringed Dragonfly Widespread in the west Common
Oxygastra curtisii – Orange-spotted Emerald Extinct Extinct
Libellula depressa – Broad-bodied Chaser Widespread in the south Widespread
Libellula quadrimaculata - Four-spotted Chaser Widespread Widespread/local
Orthetrum coerulescens - Keeled Skimmer Scarce Locally Common
Orthetrum cancellatum – Black-tailed Skimmer Widespread in the south Local/expanding
Crocothemis erythraea – Scarlet Dragonfly Rare immigrant Rare immigrant
Sympetrum striolatum – Common Darter Common Very Common
Sympetrum fonscolombei – Red-veined Darter Immigrant Immigrant/Scarce resident
Sympetrum flaveolum – Yellow-winged Darter Scarce immigrant Scarce immigrant
Sympetrum sanguineum - Ruddy Darter Scarce/Local Rare
Sympetrum danae – Black Darter Widespread/local Locally Common
Old records for the Red-eyed Damselfly - Erythromma najas, the Variable Damselfly - Coenagrion pulchellum and the Scarce Chaser - Libellula fulva have not stood up to close scrutiny. In view of this these species are not considered to have been substantiated as ever having occurred in Cornwall. This is reflected in their absence from the distribution maps in Merritt et al. (1996).
Cornwall Dragonfly Group
The Cornwall Dragonfly Group was set up in 1989 to provide a forum for local recorders to share information and to promote a high level of recording in the county. The CDG newsletter has contained a wealth of information over the years including tetrad maps for every species found in the county, earning a reputation as one of the best of its kind in the country. Indeed the data generated by the group has provided conservation organisations with a valuable resource. The group’s field meetings have also provided a relaxed and friendly atmosphere for recorders of all abilities to learn more about these fascinating insects. Sadly however the group has been dormant since 2004, and perhaps just needs some fresh blood at the helm!
Useful addresses
County Recorder for Dragonflies/Local contact for the Dragonfly Recording Network/Cornwall Dragonfly Group: Mr S. P. Jones, Herland Bungalow, Godolphin Cross, Helston, Cornwall, TR13 9RL.
Odonata Records Committee/ Migrant Dragonfly Project: Mr A. J. Parr, 10 Orchard Way, Barrow, Bury St. Edmunds, Suffolk, IP29 5BX.
British Dragonfly Society: Henry Curry, British Dragonfly Society Secretary, 23, Bowker Way, Whittlesey, Peterborough, PE7 1PY This e-mail address is being protected from spambots. You need JavaScript enabled to view it
References
Askew, R.R. 1988. The dragonflies of Europe. Colchester: Harley Books.
Brooks, S. 1997. Field guide to the dragonflies and damselflies of Great Britain and Ireland. Hook: British Wildlife Publishing.
Cham, S. 2007 Field guide to the larvae and exuviae of British Dragonflies Volume 1: Dragonflies (Anisoptera). British Dragonfly Society.
Corbet, P.S. 1962. A biology of dragonflies. London: Witherby (Reprinted 1983, Faringdon: Classey).
Corbet, P.S. 1999. The behaviour and ecology of Odonata. Colchester: Harley Books.
Corbet, P.S., Longfield, C. & Moore, N.W. 1960. Dragonflies. London: Collins, New Naturalist Series no. 41 (Reprinted 1985).
Hammond, C.O. 1983. The dragonflies of Great Britain and Ireland. Colchester: Harley Books.
Jones, S.P. 1993. Cornwall Dragonfly Group Newsletter, No. 3.
McGeeney, A. 1986. A complete guide to British Dragonflies. London: Jonathan Cape.
Merritt, R., Moore, N.W. & Eversham, B.C. 1996. Atlas of the dragonflies of Britain and Ireland. Huntingdon: JNCC/ITE.
Miller, P.L. 1987. Dragonflies. Cambridge: Cambridge University Press, Naturalists’ Handbooks No.7.
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