DMG Newsletter 2011 Issue 3 June Email Version
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PleasePlease reply reply to: to:The The Secretary/Treasurer Secretary/Treasurer RoyRoy McCormick McCormick 36 Paradise36 Paradise Road Road TEIGNMOUTHTEIGNMOUTH DevonDevon TQ14 TQ14 8NR 8NR Telephone:Telephone: 01626 01626 779543 779543 [email protected] NEWSLETTER 2011 ISSUE 3 (JUNE) What a difference a month makes! After the hottest April on record we were plunged into a drab and dreary May, with about average temperatures but little sunshine by day and lots of clear cold nights – the worst combination for moth enthusiasts. In spite of all this, there are some very exciting sightings to report in this issue of the newsletter. We, along with the whole coastline of southern and south-eastern England, recently received an astonishing influx of Itame brunneata Rannoch Looper. This is a rare migrant everywhere in Britain apart from central Scotland, where it is resident. There was a ‘massive’ arrival of Rannoch Loopers in 2009 (detailed in Atropos 40) and another such immigration took place at the beginning of June this year. Huge numbers of moths must have been involved as simultaneous captures took place from Suffolk to Cornwall on the night of 3rd June, with one lucky recorder on the Essex coast catching 10!!! Astonishing, when you consider that fewer than 50 migrant Rannoch Loopers had ever been caught in Britain prior to 2009. Devon records that we know of to date include two in Barry Henwood’s garden trap Rannoch Looper (Roy McCormick) in Abbotskerswell on 3rd June, one caught by John Walters near Buckfastleigh on 5th June and one by a new member Bill Hudson in Newton Abbot also on 5th June (shown in image). These are the first ever Devon records of Rannoch Looper. Also worthy of mention are Paul Butter’s records of Orthosia populeti Lead-coloured Drab. Four were caught in his garden near Okehampton on 25th March, two on 27th March and two on 1st April. This is a scarce moth in Devon with no records of it at all in 2010, and only occasional sightings in other recent years. However, the pick of the crop must be Zygaena lonicerae Narrow-bordered Five-spot Burnet, discovered in Devon for the first time in a century, which is reported in detail below. So plenty to read about and plenty of reasons to record moths. At the end of the newsletter, you’ll also find details of forthcoming field events, some of which are newly organised. Why not come along and enjoy a night out? Happy mothing! Richard Fox Devon Moth News I am pleased to report exciting news, that is the discovery of Zygaena lonicerae , Narrow-bordered Five-spot Burnet in Devon. In July 2010 I received an e-mail from Pete Bowers asking for help in identification of burnet moths with five spots on each forewing that he had seen near Sampford Peverell. They had to be either Z. trifolii , Five- Members of Council: Richard Fox, Chairman; Roy McCormick, FRES, Secretary/Treasurer; Rob Wolton, Conservation; Nicola Bacciu, Membership & Distribution; Barry Henwood, Ordinary Member. spot burnet or Z. lonicerae , Narrow-bordered Five-spot Burnet. I shall from now on refer to them by the specific names as the common names are so long winded. There are hitherto no authenticated records of lonicerae in Narrow-bordered Five-spot Burnet Devon. However, trifolii does occur. Nationally, it has two Z. lonicerae in Devon (Pete Bowers) subspecies trifolii decreta found in marshy habitat where the larvae feed on Greater Bird’s-foot Trefoil and trifolii palustrella found on chalk downland where the larvae feed on Common Bird’s-foot Trefoil. It is subspecies trifolii decreta that occurs in Devon – the Culm Grasslands, for example, have good populations. Although Pete had told me there was no Greater Bird’s-foot Trefoil where he found the moths, I replied saying that his moths must be Z. trifolii decreta as the other possibilities did not occur in Devon. However, I did say that I looked forward to hearing what the larvae did in the spring. As adults, trifolii and lonicerae are very difficult to tell apart. I shall not go into the differences here (you can see the new Guide to Selected Difficult Species published by Butterfly Conservation for a recent review). The textbooks are helpful, but the two species are difficult to identify and the genitalia do not help. They are most easily distinguished as larvae, and of course the habitat and foodplant help. The larva of lonicerae has much longer hairs than that of trifolii (see images below). Towards the end of April 2011, Pete e-mailed me a photo of a larva which was instantly recognisable as that of lonicerae . It was feeding on Meadow Vetchling, one of that species’ main foodplants. On 4th May I visited the site with Pete. Larvae were abundant on Meadow Vetchling and we also found one feeding on Red Clover, the other main foodplant of lonicerae . I have now had the identification further confirmed by Dr Gerry Tremewan (a world authority on burnet moths) who was most interested in the discovery. Z. lonicerae larva (left) from the newly discovered Devon population, showing long hairs, and Z. trifolii (right) with short hairs (Barry Henwood) There are two main sites with the moth, both on the embankments of the North Devon Link Road near Sampford Peverell, about 1km apart and each about 300-400m long. The moths are well established as Pete counted 392 adults on a transect walk on one of the sites on 20th June 2010. He estimates the total population on that site must have been in the thousands. Gerry Tremewan told me that lonicerae is an opportunist species, readily colonising habitat that becomes available and that it is known to spread along major roads. The embankments were created in the mid 1980s as part of the North Devon Link Road construction. Pete first discovered the moths in 2003, which was the first year he monitored the site. Roy McCormick’s book The Moths of Devon gives a few records of lonicerae from over 100 years ago and then a record from Halwell in 1962, which was reported as a flourishing colony with confluent spots on the wings. Roy 2 points out in his book that the mention of confluent spots suggests that it was a misidentification of trifolii . I agree with Roy’s view as lonicerae is not subject to much variation at all in the appearance of the adults. So it would appear that the recent sightings are the first in the county for over a century. Other sightings can’t really compete with this discovery but are noteworthy nevertheless. The warm spring weather has resulted in early emergence of various species of moths. For example I recorded Laothoe populi , Poplar Hawk- moth and Smerinthus ocellata , Eyed Hawk-moth in April. I cannot recall having seen them before May in any previous year. During April I noticed a tiny micro-moth Heliozela sericiella flying in sunshine in and around the edge of a Dartmoor wood. They were so abundant, I must have seen hundreds of them. The larva is not easy to find as if mines the twig, then petiole, then midrib of an oak leaf and only at the end of the larval stage does the mine extend into the blade of the leaf, from which the larva cuts out a case and drops to the ground. Many of you will have observed the disfigurement of Horse Chestnut trees by the larvae of Cameraria ohridella mining the leaves. This is a recent colonist which has spread rapidly and built up huge numbers. On 21st April I was looking at some trees in Torquay while waiting for my car to be repaired. The adults were amazingly abundant, sitting on the tree trunks. On one tree, within the circular area created by opposing my thumb and index finger I counted 14 moths – that is an area of just 20cm 2. It is worth mentioning some records from 2010 from Peter Vernon at Colyford that didn’t make it into the DMG Annual Report for the year. These are Earias clorana , Cream-bordered Green Pea on 2nd, 10th and 24th July, the Pyralid Donocaula forficella on 14th July (presumably wandered from Axe Estuary reedbeds) and the Plume moth Platyptilia pallidactyla on 20th July. Cream-bordered green pea was first recorded in Devon in 1989, but Colyford represents a new site. I certainly never caught it at Colyton where I ran a garden trap in my teenage years in the 1970s. A word of caution for those of you looking out for it is that it must be distinguished from the Tortricid moth, Tortrix viridana . While walking on the coast in Cornwall recently I found several larvae of Lasiocampa trifolii , Grass Eggar. They are conspicuous on the ground and a good way to record this species. If you are walking on the coast do look out for them, they will probably be fully fed about mid-June. Barry Henwood Dingy Mocha still at Hollow Moor The Dingy Mocha Cyclophora pendularia is a rare moth with its stronghold in Dorset and south-west Hampshire. It is a priority UK Biodiversity Action Plan species because it has been lost from many sites in recent decades. The only current known site for the moth in Devon is at Hollow Moor, a very large Culm grassland site in West Devon, where it was discovered in 2006 after a single male, presumed to be a wanderer, was trapped on a very small Culm grassland site not far away in 2005. After catching adults on Hollow Moor in actinic light traps, larvae were found later that summer by beating willow, the foodplant.