Worcestershire Record No. 23 November 2007 pp. 38-41

Harry Green

It started on the 8th August 2007. My daughter Rachel and grandson Ruben took me to look at a small rough grassland on Chapel Farm, Netherton, near Elmley Castle, where they thought we might find some interesting insects. We wandered slowly through the field and I caught a few hoverflies. Rachel called “What’s this green grasshopper?” Another Meadow Grasshopper I thought but when I went to look, there, perched on her hand, I saw, much to my astonishment, a Long-winged Conehead Conocephalus discolor. No more were seen that evening but a plan was laid to visit next day. I went home and rummaged around to find my electronic orthoptera detector, a modified Mini-3 Bat Detector by Ultra Sound Advice bought several years previously. I also listened to the excellent CD (Ragge & Reynolds 1998) of orthopteran sounds to remind myself of cricket and grasshopper songs. Because I can’t hear most of them (ageing ears) this involved pointing the detector at the loudspeaker of the CD player! Next day we set off to walk to the meadow. On the way I switched on the detector. There were crickets all over the place! It dawned on me they were Roesel’s Bush-crickets Metrioptera roeselii. They were calling at regular intervals along a fence line with rough grass verges and also in the meadow. In all we estimated at least 100 individual singing males. No Long-winged Coneheads were found. The next lesson was that it is extremely difficult to see these animals even when pointing a vibrating detector straight at where they should have be! And if a sweep net is passed through the grass where they are calling they simply drop to the ground! However, we did catch a big female Roesel’s with very long wings (macropterous form). The significance of this did not strike me at the time: female Roesel’s are normally flightless.

Over the next couple of weeks I found both species in rough grassland at the north end of Tiddesley Wood near Pershore, at Rough Hill Orchard near the south end of Tiddesley Wood, and in rough grassland adjacent to the Worcestershire Wildlife Trust headquarters at Lower Smite Farm, near Worcester. It was about this time I started to get excited! As it happened there was a visit planned to Kemerton Lake and environs looking for late summer bees. Naturally I took the detector and soon found coneheads in the rushy margins of the lake. This seemed the wrong habitat for Long-winged Coneheads so my beginner’s confidence level dropped and I wondered if I was hearing Short-winged Coneheads Conocephalus dorsalis. After a few sweeps with the net I caught a female conehead and it had short wings! Eureka moment! I knew we only had records from two other Worcestershire sites of Short-winged Coneheads. I took it home in a large jar and left it on one side for the night. By morning it had moulted … … and turned into a Long-winged Conehead! Later I found a perfect picture of a last instar nymph of Long-winged Conehead which explained my error (Evan & Edmondson 2007). By this time my naturalist friends were being bombarded with emails suggesting they got out more and looked for these crickets. Worcestershire Orthoptera Recorder Gary Farmer unfortunately had little time to look (he had to go to work, unlike us idle retired folk!) but he did find them near Solihull where he worked and we arranged for him to visit Kemerton Lake in early September. Fortunately he confirmed there were no Short-winged Coneheads at that site but we found lots of Long-winged.

By the time Gary visited Kemerton on 9th September I had been rampaging round the county searching for crickets and my level of expertise had risen greatly. By then I had found one or both species at 83 sites in Worcestershire. Most of these were fairly open roadside verges with tall coarse un-cut grasses and this turned out to be a favoured habitat. Once my eye was in for the habitat I was able to drive around the county with the detector pointing out of the window and every so often the gadget buzzed to confirm another record! It is best to have a passenger to help with this technique! Grandson Ruben was a great asset, mainly because he could hear the crickets himself without the detector – eleven-year-old-ears are remarkably sensitive! Driving along he would simply chant “Roesel’s” … … Long-winged … … dark bush cricket … … Roesel’s! A never-ending stream of records.

Meanwhile several other naturalist friends had found their dusty old bat detectors. John Tilt found both species round Grafton Wood and at Croome Park and in Herefordshire! Tony Simpson found both on road verges near Stoulton. Gary Farmer found them near Inkberrow. I set out to try and discover how much of Worcestershire had been invaded. On warm days I took advantage of any journey round the county to look for them and made several extensive loops along little-frequented country lanes on the hunt. In suitable habitat I found them throughout SE Worcestershire and over the county boundary into nearby Warwickshire; right across south Worcestershire to the Malvern Hills; and throughout the countryside north of Pershore. Records petered out in central Worcestershire though I found both near Tardebigge. Numbers also seemed smaller west of the Severn, especially north of the River Teme. Brett Westwood and I found a solitary Long-winged in a small patch of rushes near the Severn at Shrawley (actually the 100th site for the season for the species!) and by a nearby pool. The A449 from Worcester to Crossway Green had good-looking verges but was disappointing and forays to either side produced only occasional records. None were found near Stourport, Kidderminster and in Wyre Forest. Northern parts of the county were not searched properly – no time. Both species may continue singing into the autumn if the weather remains warm although the males become very thin and weak and the speed of stridulating drops considerably as the temperature drops.

By 30th September I had records for one or both species on 150 occasions, most at different sites. Ruben found the 151st site near Kemerton on 6th October. In all I recorded Long-winged Coneheads at 123 sites, Roesel’s Bush-crickets at 62 sites and both were recorded together on 34 sites. I became ill on 3rd October which brought the 2007 great cricketing season to a sudden end for me!

The plan is to produce a distribution map of all the 2007 records for Worcestershire Record in April 2008. By then all records should be on the Worcestershire BRC database. I am aware of several records that are not on my own list. Gary Farmer tells me of a Roesel’s Bush-cricket found in a garden in Evesham – maybe the first garden record! He has several records himself including nymphs of both species found at Wick Grange Farm on the Recording Field Day 9th June 2007. At the time of this last I did not see the nymphs myself and the significance of the records completely passed me by!

Ragge (1965) states that Long-winged Coneheads are known only from Dorset, parts of Hampshire, Sussex and Kent, and the Isle of Wight, bur he does not even present a distribution map, and writes that the species is mainly coastal. According to Marshall & Haes (1988) Long-winged Coneheads probably settled in England sometime early in the 20th century. They report two population explosions following hot summers, one in the 1940s, another in the early 1980’s. Nevertheless the species remained restricted to a few southern counties in southern England and a distribution map in their book is similar to Ragge’s description. In the 1990s the range again expanded and a map accessed via the NBN Gateway shows a very considerable inland invasion and also to SW English counties. It is apparent that few records have been added to the NBN site since 2000. Peter Sutton, in a series of reports in British Wildlife, has drawn attention to a continuing expansion of range. The most modern distribution map I have seen in Evans & Edmondson (2007) which shows the species throughout southern England roughly south of a line running from south Wales to central Norfolk with extensions north into Leicestershire and Gloucestershire. Widgery (2007) in a report on Gloucestershire Orthoptera 2006 reports many records and suggests that Long-winged Coneheads occur throughout the county. He (in lit 2007) reported a continuing expansion in 2007 and indeed I found the species in many places on the verges by the A38 between Tewkesbury and Twigworth in 2007.

Modified from Haes & Marshall 1988. Distribution of Long-winged Conehead Conocephalus discolor in Britain prior to 1988.

Click on this link:
http://www.searchnbn.net/gridMap/gridMap.jsp?allDs=1&srchSpKey=NBNSYS0000006823
for Long-winged Conehead Conocephalus discolor distribution in Britain & Ireland according to the NBN Gateway. Records to around 2000.

The first record for Worcestershire was reported by John Meiklejohn from a road verge south of Upton-on-Severn 8th September 2003 (Worcestershire Record No 15 November 2003). Gary Farmer reported a small colony in Redditch in 2005 (Worcestershire Record No 19 November 2005) and reported that it was spreading in the NE of the county in 2006 (Worcestershire Record No.21 November 2006). 2007 has seen a further great extension in range although the species may have been present in larger numbers previously and unrecorded because many people cannot hear the high-pitched song and the species is good at eluding sweep nets.

Ragge (1965) gives the distribution of this species as coastal and mainly estuarine in Hampshire, the counties round London and near the Humber. Marshall & Haes (1988) consider the species to be a last post-glacial arrival and their distribution map reflects Ragge’s comments together with additional isolated colonies in southern Ireland and on the central Welsh coast. A distribution map accessed via the NBN Gateway shows a great expansion of range round London with more distant records on the central Welsh coast, Lancashire, Southern Ireland and an amazing dot in the northern Hebrides. These records, like those for Long-winged Coneheads, all appear to be before 2000. Peter Sutton has since added information on an increasing range in his British Wildlife reports. Evans & Edmondson (2007) show a further great extension of range covering the whole of SE England to the Midlands, and with records in West Wales. Widgery (2007) mentions a continuing spread in Gloucestershire and notes that both this species and Long-winged Coneheads may be found in similar habitats and that generally the latter arrive before the former.

Distribution of Roesel’s Bush Crickets Metrioptera roeselii in Britain & Ireland according to Ragge 1965 plotted by Vice county (Worcs VC 37).

Distribution of Roesel’s Bush-cricket Metrioptera roeselii in Britain & Ireland according to Marshall & Haes 1988

Click on this link:
http://www.searchnbn.net/gridMap/gridMap.jsp?allDs=1&srchSpKey=NBNSYS0000006822
  for Records of Roesel’s Bush-cricket Metrioptera roeselii according to the NBN. Records before about 2000.

The first records for Worcestershire were reported by Gary Farmer (Worcestershire Record No. 19 November 2005) and I quote “In 2005 during a ‘Recorders’ meeting I found a large colony in Arrow Valley Park in Redditch. This colony must have been overlooked for a year or two to have built up such numbers. A week later Roesel’s Bush-crickets were found in the south of the county on Bredon Hill (P. Taylor and J. Hardy). At the same time J. Day found this species in West Gloucestershire, so there must be more to find in Worcestershire”. Interestingly Roesel’s were next found during the 2007 Recorders meeting at Wick Grange farm near Pershore on 7th June as nymphs. This finding should perhaps have alerted us to the possibility of things to come later in the summer!

Both these species have a somewhat similar life history. Using large ovipositors the females insert eggs into grass stems and these over-winter and hatch the following May. By successive moults the nymphs pass through five (coneheads) or six (Roesel’s) instars. Adults start to appear in July and may survive to November in warm weather conditions. In years when good survival produces dense over-crowded populations larger numbers of free-flying macropterous forms occur. Female Long-winged Coneheads develop even longer wings than usual and normally flightless female Roesel’s Bush-crickets develop long wings. Following fertilization these free-flying females appear to disperse to new habitat so extending the range. One can speculate that warm winters lead to better over-winter survival of eggs. Over-crowding in the following summer induces the development of macropterous forms. Good summer survival and good weather perhaps increases the dispersion of females. New colonies also tend to produce more macropterous forms and Thomas et al (2001) suggest that dispersive forms which survive well may be more generalist in selection and use of habitat and more inclined to disperse in the future. This may explain the change of apparently coastal species becoming wide spread inland in drier more grassy habitats.

I regret that my Great Cricketing Summer did not start earlier! It was sheer chance that it started at all. I also regret that it did not continue into October although poorer weather conditions probably finished off most of the crickets quite early on in the month. A further regret is that there just was not enough time to explore central north Worcestershire, the Teme Valley, and over the Malvern Hills into Herefordshire. And how many crickets were there off-road? I hope readers will be encouraged to search for these crickets in summer 2008 and to send records into the WBRC and perhaps let me know if they find any and would like identity checked. It is not often we get the chance to document the invasion of our county by a new species!

Crickets and Grasshoppers do not of course start singing until later in the summer after they have passed through the nymphal stages. Detection of crickets is not easy. Most people over 40 cannot hear them and neither can quite a few younger ones. A bat detector or a keen naturalist aged about eleven years are both great assets! Simple bat detectors are quite adequate as the frequency of cricket sounds are nor far above the sensitivity of human hearing. Recognising the sounds is another matter but help can be found using the Ragge & Reynolds CD and book. There are also several web sites that are helpful. I wished to record the sounds I heard and John Tilt recommended a Samsung YH-925 MP3 Player with a line-in input socket which could be connected directly to the detector. This MP3 player is somewhat elderly in modern gadgetry terms but again my daughter found one on eBay at a very reasonable price! Using this and free software AUDACITY downloadable via the internet enables you to look at simple oscillograms which can usefully compared with the diagrams in Ragge & Reynolds (1998).

In writing this article I almost have a feeling of guilt towards Gary Farmer, our very able Orthoptera Recorder for Worcestershire. During the excitement of finding the crickets his advice and comments were very helpful and I am sorry that restraints of family and work prevented him from getting out more! Similarly my friends Brett Westwood and John Tilt took the sudden outbreak of orthopteran madness in their stride and joined in as far as they could. Brett’s influence led to an interesting Radio 4 broadcast on Shared Earth (you can probably find it somewhere on the Radio 4 website) with Dylan Winter when he accepted the challenge that “he wouldn’t be able to find one”, got down on his knees and did so! Robert Homan kindly sent me information from The Gloucestershire Naturalist and John Widgery also sent information from that county. And Ruben got his picture of Roesel’s Bush-cricket on the Radio4 web site as well as helping find innumerable crickets. Truly a Great Summer Cricketing!

References to Worcestershire Record in text.