Hemiptera) of Cornwall & the Isles of Scilly

THE LAND AND FRESHWATER BUGS (HEMIPTERA) OF CORNWALL & THE ISLES OF SCILLY by Keith N.A. Alexander COVER PHOTOGRAPHS Cape Cornwall Corizus hyocyami Dicranocephalus agilis © Roger Key Enoplops scapha Piezodorus lituratus Dannonchapel Calocoris roseomaculatus Trapezonotus ullrichi on oxeye daisy at Mullion © Dr Bernard Nau THE LAND AND FRESHWATER BUGS (HEMIPTERA) OF CORNWALL & THE ISLES OF SCILLY Keith N.A. Alexander CISFBR & ERCCIS OCCASIONAL PUBLICATION No. 2 2008 & ERCCIS OCCASIONAL PUBLICATION No. 2 2008 Design and typesetting by Wheal Seton Press, Dr Colin French, 12 Seton Gardens, Weeth Road, Camborne, Cornwall TR14 7JS, U.K. All rights reserved. No part of this publication may be reproduced, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission of the copyright owners. Copyright © KNA Alexander & CISFBR. ISBN: 0 9534613 2 7 Contents 1 INTRODUCTION..................................................................................................1 2 SPECIAL.FEATURES.OF.THE.CORNISH.FAUNA........................................1 3 CHANGING.DISTRIBUTIONS...........................................................................3 4 SPECIES.TOTALS................................................................................................3 5 EQUIPMENT.FOR.FIELDWORK......................................................................4 6 RETENTION.OF.VOUCHER.SPECIES.............................................................4 7 USEFUL.LITERATURE.......................................................................................4 8 NATIONAL..RECORDING.SCHEMES..............................................................6 9 RECORDING.IN.CORNWALL............................................................................6 10 THE.CATALOGUE.OF.LAND.AND.FRESHWATER. BUGS.OF.CORNWALL.&.THE.ISLES.OF.SCILLY.....................................6 10.1 Sources of Records ................................................................................................. 6 10.2 Area of Study .......................................................................................................... 8 10.3 Nomenclature .......................................................................................................... 8 10.4 Status ....................................................................................................................... 8 10.5 Organisation of 10km Square Records................................................................. 8 10.6 Abbreviations used for main recorders ................................................................ 8 10.7 Details of species ecology and local records in current taxonomic order ........ 11 Acknowledgements.....................................................................................................145 Bibliography...............................................................................................................145 Index...........................................................................................................................151 1 ��INTRODUCTION The bugs are a diverse group of insects, including such well-known animals as shield bugs, pond skaters, water boatmen, greenfly, and whitefly. Those species which have been found within Cornwall and the Isles of Scilly are listed in the following section and information is provided on their national and local status, their habitat associations, and all known records are listed by 10km square. This format has been pioneered by Duff (1993) as a way of making records more accessible to people who are not familiar with a particular county and at the same time providing a picture of the known distribution of each species in the county. Thus a species that has been recorded many times from a small area is readily seen to be of restricted distribution, whereas the number of records from the range of localities within that area might otherwise give a false impression of a widespread distribution. 2 ��SPECIAL FEATURES OF THE CORNISH FAUNA The Cornish terrestrial Heteroptera fauna is of especial interest to British entomologists because it includes a relatively species-rich assemblage of Mediterranean and Atlantic (west European) species which is unique in Britain. Good examples of the Mediterranean species are the seed bug Henestaris laticeps and the shield bug Geotomus punctulatus; of the Atlantic species, the plant bug Capsodes sulcatus, the shore crevice bug Aepophilus bonnairei and the microphysid Myrmedobia inconspicua. The plant bug Pachylops bicolor is also of especial note as - although widespread on common gorse Ulex europaeus in southern England - it only occurs elsewhere in western France. The shore crevice bug Aepophilus bonnairei is a speciality of the rocky coasts of SW Britain and Ireland, west and south-west France and the Atlantic coasts of Spain and Morocco. Cornwall and the Isles of Scilly are the sole GB area for the following species: the shield bug Geotomus punctulatus, the seed bug Pterotmetus staphyliniformis, the beetbug Piesma quadratum spergulariae (endemic to the Isles of Scilly), thyme lace bug Lasiacantha capucina, and the plant bug Halticus macrocephalus. The greatest variety of local specialities is associated with the freely draining dry soils of the sea cliffs and the wind-blown sand habitats. The sole GB locality for Geotomus punctulatus is the loose sand of Sennen Cove but the population appears robust and not under any particular threat. The seed bug Emblethis griseus is the other Sennen Cove speciality, and also occurs in the Isles of Scilly and, formerly, at Sandwich Bay (Kent) but nowhere else in Britain. The shield bugs Odontoscelis fuliginosa and Legnotus picipes have only been found at Perranporth. Other sand dune specialities are more widespread – especially along the north coast - and include another shield bug Odontoscelis dorsalis. Sea cliff specialities include the seed bug Pterotmetus staphyliniformis - confined to the heathy cliffs of West Penwith - and thyme lacebug Lasiacantha capucina which is more widespread on the western cliffs, as well as the seed bug Trapezonotus ullrichi which is more widespread again, on ox-eye daisy flowering in the maritime grasslands. Although national rarities these are all readily to be found and appear to be under no threat. There is also a wide range of other species, more widespread nationally, but of restricted occurrence nonetheless, e.g. the seed bugs Heterogaster artemisiae and Tropistethus holosericeus. The Lizard peninsula has a few of its own specialities, particularly species more typical of calcareous grasslands such as the seed bugs Drymus pilicornis, Taphropeltus hamulatus and Catoplatus fabricii, as well as the leafhoppers Ulopa trivia and Agallia brachyptera. Some of these may prove to be more threatened than the south-western specialities – searches for T. hamulatus have failed to find it in recent years, for example, while the Drymus has not been reported since 1970 and Catoplatus since 1965. The majority of these species are well represented in the currently designated Sites of Special Scientific Interest but the unique fauna of the loose sand areas of Sennen Cove appears to have slipped through between the neighbouring rocky coast SSSIs and appears unprotected. The entire British population of the shieldbug Geotomus punctulatus occurs here together with a remarkably rich variety of other Nationally Scarce and British Red Data Book bug species. The omission of this extraordinary area from the SSSI series is remarkable. 1 Wetlands feature strongly amongst the fauna too, and land drainage for agriculture will have had serious consequences for these species. A number have not been found in the county for decades and are assumed to have become extinct: Eysarcoris aeneus – recorded in a rushy meadow in 1975, Nabis brevis and Tytthus pygmaeus both noted at Marazion in 1965, Lamproplax picea last seen in 1963, Dictyla convergens noted at Loe Pool in 1919, and Acompus rufipes – not seen for nearly 100 years. Another suite of species which will have been decimated by the increasingly intensive agriculture of the past fifty years is the fauna of species-rich arable land. Two Nationally Scarce seed bugs are currently only known in the county from the arable fields of West Pentire: Aphanus rolandri and Scolopostethus pictus (Alexander, 2005). Changing woodland management has also had consequences for the bug fauna. The ungrazed woods have largely been left unmanaged in recent decades and species which were formerly favoured by active coppice cutting have now largely died out, e.g. both Sehirus biguttatus and Dicranocephalus medius appear to be extinct in the county. A wide range of bugs associated with trees, shrubs and dwarf shrubs appear to be of restricted occurrence locally. The deadwood species Xylocoris cursitans and Aradus depressus are known from very few sites, all in the east of the county and X. cursitans appears confined to the cluster of old growth sites of Boconnoc, Ethy and Lanhydrock Parks along the lower Fowey valley. The orchard speciality Physatocheila smreczynskii is another Boconnoc speciality but may be expected in other areas with old apple orchards. One facet that became apparent during the compilation of this list is the surprising rarity of birch bugs in the county. The birch shieldbugs Elasmucha grisea and Elasmostethus interstinctus, the seed bug Kleidocerys resedae

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