ORTHOPTEROID INSECTS

E.C.M. Haes and M. Lee

These insects comprise four major Orders with British representatives. Orthoptera (Bush-crickets, Crickets, Ground-hoppers and Grasshoppers); Dictyoptera (Cockroaches); Dermaptera (Earwigs) and Phasmida (Stick-insects). The Orthoptera, particularly, may seem to be very significant in the insect fauna of Cornwall. This is created by the swarms of grasshoppers around the cliff top and duneland footpaths and to the evening chorus of the impressively large Great Green Bush-cricket Tettigonia viridissima, which is numerous around most of the main coastal resorts and adult when most likely to be noticed - during the summer holiday season. However, although a good place to study the group, post-1983 records for Cornwall show only a total of 22 native and 10 established resident orthopteroid species, out of a total of 35 native and 15 established residents for mainland Britain as a whole, i.e. excluding the Channel Islands and the Isle of Man (a further four migrants and one casual have been recorded in Cornwall post-1983). Tantalising evidence of a possible RDB1 further native species came in 2004 with two records of the Giant or Tawny Earwig Labidura riparia. Were these to be confirmed, they would be of national importance, as the first UK record for over 70 years. To set the native species in their national context, Cornwall has eight of the 10 bush-crickets, none of the four crickets/mole crickets, all three ground-hoppers, six of the 10 grasshoppers, two of the three cockroaches and three, possibly four, of the five earwigs. Only one native Red Data Book species, the RDB1 Mole-cricket Gryllotalpa gryllotalpa, is certainly known to have been resident in Cornwall, but, not having been recorded here since 1962, is undoubtedly extinct. There are several Nationally Scarce native species with strong populations in Cornwall. The Woodland Grasshopper Omocestus rufipes Zetterstedt, deserves a mention, as its strong populations are found in coastal heathland (especially around The Lizard), a habitat unknown elsewhere in Britain. None of the post-1983 species are subject to a Biodiversity Action Plan (BAP), although this would have applied to the extinct Mole Cricket. There are two early Victorian records from W. P. Cocks for the BAP and RDB2 Wart-biter Decticus verrucivorus, but these have never been confirmed. Cornwall holds the greater part of the UK’s naturalised stick-insects, which have been a component of the county fauna since the early part of the twentieth century. The very localised colonies of the Unarmed Stick-insect Acanthoxyla inermis Salmon are widely distributed throughout the county, yet outside of Cornwall there is just a single Devon colony in Plymouth, and it is present in a single garden in West Sussex which originated from Cornish insects collected in 1999. Nymphs were found outdoors in Poole during 2006, but were not seen in 2007, and a colony in a Somerset nursery has not been seen for many years. Outside of Cornwall, the Prickly Stick-insect Acanthoxyla geisovii (Kaup) has only been recorded in Devon, principally around Torbay. Two migrants are worth noting, Large Cone-head Ruspolia nitidula and Sickle-bearing Bush-cricket Phaneroptera falcata, where the Cornish records for both species were the first natural UK records (albeit the latter was in 1881, with no other UK records until 2006). Whilst neither led to subsequent colonisation here, both species have become tentatively established on the south coast of England in the last few years, and further expansion may be expected. They could both turn up here again. Two species have been deleted from those in the 1997 Cornwall Red Data Book, due to increased number of national records: Long-winged Cone-head Conocephalus discolor and Short-winged Cone-head C. dorsalis. Since the Long-winged Cone-head arrived here from France c. 1989, colonies are now widely distributed over the southern part of the Duchy, some of which around the Fal Estuary and Loggans Moor NR are large and spreading. It has yet to be found north of an approximate line from Newquay to Saltash. There are extensive populations on the Isles of Scilly. The Short-winged Cone-head has been recorded on the Gannel, Fowey and Tamar/Lynher salt marshes. Unrecorded from the Fal, and the Camel is unsuitable. Present on several of the islands in the Isles of Scilly. The main threats to both common and rare orthopteroids in Cornwall is excessive passage of feet and wheels over dunes and cliff paths; the mechanical shaving of Cornish hedges, and the continuing coniferous afforestation of valleys and heathy uplands. Significantly one of the best sites for Orthoptera in Cornwall is on land owned by the Ministry of Defence and closed to the public. Information for these accounts is taken from Marshall & Haes (1988), Haes and Harding (1997), Haes (2004 and 2005) and Lee, M. (2006 and 2007). Orthopteroid Post-1983 Conservation Status Summary –

RDB1 0 (+ 1 possible, + 1 extinct)

RDB2 3 (+ 1 unconfirmed)

RDB3 0

RDB Total 3 (+ 1 possible, + 1 extinct, + 1 unconfirmed)

BAP 0 (+ 1 extinct, + 1 unconfirmed)

Na 1

Nb 8 (+ 2 extinct)

NS Total 9 (+ 2 extinct)

LS 3

1. Grasshoppers and crickets

Platycleis albopunctata Grey Bush-cricket

Metrioptera brachyptera Bog Bush-cricket

Ruspolia nitidula Large Cone-head

Phaneroptera falcata Sickle-bearing Bush-cricket

Acheta domesticus House-cricket

Gryllotalpa gryllotalpa Mole-cricket

Stenobothrus lineatus Stripe-winged Grasshopper

Omocestus rufipes Woodland Grasshopper

Gomphocerippus rufus Rufous Grasshopper

2. Cockroaches

Ectobius lapponicus Dusky Cockroach

Ectobius pallidus Tawny Cockroach

Tetrix ceperoi Cepero’s Ground-hopper

Ectobius panzeri Lesser Cockroach

3. Earwigs

Labia minor Lesser Earwig

Forficula lesnei Lesne’s Earwig

Labidura riparia Giant or Tawny Earwig

4. Stick-insects

Acanthoxyla geisovii Prickly Stick-insect

Acanthoxyla prasina

Acanthoxyla inermis Unarmed Stick-insect

Clitarchus hookeri Smooth Stick-insect

Bacillus rossius Mediterranean Stick-insect