Atropos migrant insect review – end September/early October 2011

The weather for the majority of September was very unsettled as a result of the tail-end of Hurricane Katia which brought strong westerly winds to our shores. However, the last week of the month and the first few days of October saw a southerly airstream resulting from anticyclonic conditions over mainland Europe. The warm conditions (with temperatures peaking at 29 degrees in the south) produced the largest arrival of immigrant moths since 2006 and some interesting butterfly and dragonfly sightings too.

The highlight on the Odonata front has been another influx of Vagrant Emperor Anax ephippiger although on a smaller scale than the spring arrival. Singles were attracted to light at Rospannel Farm, Cornwall, on 2 October (B. Hocking) and at Clone, Co. Wexford, on 1 October (M. O’Donnell). The Wexford dragonfly was only the second Irish record and first since 1913! A further singleton was discovered inside a house well to the north at Annan, Dumfries & Galloway, on 2 October (R. Slee).

A possible Green Darner Anax junius seen on the west coast of Ireland at Achill Island, Co. Mayo, on 22 September was frustratingly never seen perched, so the identification could not be clinched (J. Jones). Three Yellow-winged Darter Sympetrum flaveolum were noted on Alderney, Channel Islands with a small arrival of Red-veined Darter Sympetrum fonscolombii including reports from the Isles of Scilly (St. Mary’s and Tresco on 2nd and 3rd October) and Badminston GP, Hampshire, on 28 September. Willow Emerald Damselflies Lestes viridis continued to be reported from Norfolk and from Suffolk - where several were located around a small farm pond at Boyton Marshes by observers watching Britain’s fourth Sandhill Crane Grus canadensis on 2 October.

A single Monarch butterfly Danaus plexippus was noted at Ringstead, Dorset, on 28 September and is perhaps surprisingly, given the predominant westerlies, the only report we have heard of this autumn. On the same day and in the same county a Long-tailed Blue Lampides boeticus was noted at Easton, Portland (G. Walbridge).

There was an increase in sightings of Clouded Yellow Colius croceus from widespread localities including a decent count of 20+ on the Lizard, Cornwall, on 29 September. Red Admiral Vanessa atalanta migration was witnessed on the Suffolk and Essex coasts on 18 September with southbound passage noted at Portland, Dorset, on 28 September. Sightings of Red Admirals were not confined to migrating insects though, as there were many sightings of gatherings of butterflies feeding on Ivy and reports from light-traps.

It has been an incredibly exciting period for moth enthusiasts with the southerly winds bringing some very rare immigrants. The highlights have been the first British record of Mediterranean Corn Borer Sesamia nonagrioides from St. Agnes, Isles of Scilly, on 2 October (M. Hicks) and a stunning Oleander Hawk-moth Daphnis nerii caught at actinic light in West Bexington, Dorset, on 21 September (R. Eden). A Passenger Dysgonia algira at Woodford Green, Essex on 9 September (R. Barfoot); Scar Bank Gem Ctenoplusia limbirena on St. Mary’s, Isles of Scilly, on 23 September (M. Scott), Tunbridge Wells Gem Chrysodeixis acuta at Tramore, Co. Waterford, on 30 September (A. Bryant) and a Slender Burnished Brass Thysanoplusia orichalcea at Nanquidno, Cornwall, on 28 September (Colin Moore) were other very exciting captures. Not as pleasing on the eye, but still very rare, were the Dark Mottled Willow Spodoptera cilium trapped in Cornwall at Sennen on 28 September (M. Elliott) and Lizard on 2 October (M. Tunmore); on St. Mary’s, Isles of Scilly, on 30 September (M. Hicks) and in Taunton, Somerset, on 4 October (J. McGill).

A sprinkling of maybe twenty intricately marked Crimson Speckled Utethesia pulchella were reported from the Isles of Scilly and Cornwall (with three light-trapped at Lizard on 4th, M. Tunmore) and from Somerset, East Sussex, Kent, London and Gywnedd in the first few days of October. At least six exquisite Purple Marbled Eublemma ostrina were recorded on the Isles of Scilly and Cornwall during this period with many reports of Small Marbled Eublemma parva – certainly some of the darker individuals relate to progeny of the earlier summer influx.

An excellent supporting cast of geometers included quite a number of Blair’s Mocha Cyclophora puppillaria (although some of these probably relate to recently established resident populations); a small influx of Portland Ribbon Wave Idaea degeneraria (Cornwall, Dorset and Isle of Wight) and a Many-lined Costaconvexa polygrammata at West Bexington, Dorset, on 29 September (D. Foot).

Death’s Head Hawk-moth Acherontia atropos records came from Alderney, Channel Islands, on 23 September (D. Wedd); Rospannel Farm, Cornwall, on 1 October (B. Hocking) and one found by day at Arne, Dorset, on 4 October.

Rare plusias included widespread reports of Ni Moth Trichoplusia ni, Dewick’s Plusia MacDunnoughia confusa recorded in Essex, Surrey, East Sussex, Dorset, Hampshire and Somerset and a Golden Twin-spot Chrysodeixis chalcites at Portland, Dorset on 3 October.

Pale-lemon Sallow Xanthia ocellaris has had a very good year with records from Isles of Scilly (the first record for the islands) Dorset, West Sussex and Suffolk almost certainly relating to immigrants. It has been a very good autumn for Clifden Nonpareil Catocala fraxini and Flame Brocade Trigonophora flammea sightings from Dorset through to Sussex and these two species must surely be temporarily established in certain areas now.

Rare immigrant pyrales associated with the late September/early October influx included records of Spoladea recurvalis, Hellula undalis, Diasemiopsis ramburialis, Uresiphita gilvata, Euchromius ocellea, Etiella zinckenella, Antigastra catalaunalis and Palpita vitrealis mostly from southern coasts. However, four recurvalis reached Co. Wexford on 1 October representing the first Irish record with five on the Isle of Man the same night. A catalaunalis was trapped well inland in Worcestershire the following night.

For the first time since 2006 decent numbers of Gem Orthonama obstipata, Vestal Rhodometra sacraria, Delicate Mythimna vitellina, Scarce Bordered Straw Helicoverpa armigera and Convolvulus Hawk-moth Agrius convolvuli were widely reported; with smaller numbers of Small Mottled Willow Spodoptera exigua, Bordered Straw Heliothis peltigera and Cosmopolitan Mythimna loreyi also light-trapped.

Other orders included sightings of Southern Oak Bush-cricket Meconema meridionale on Portland, Dorset on 5 October – the second island record. There were many reports of Western Conifer Seed Bug Leptoglossus occidentalis along the south coast (particulary Dorset) although 17 at Orfordness, Suffolk, on 1 October was the first site record.

Atropos would like to thank you for your contributions to the Flight Arrivals webpage. Hopefully there is still some excitement left in the remainder of October and we look forward to hearing about your sightings.