nature-shetland.co.uk

An independent, non-commercial site to collect and disseminate information on the natural history of Shetland

contact us

About these pages

Nature in Shetland

winner of a Shetland Environment Award 2004

Home
Up

Shetland Entomological Group

 

 

Overview of Moths in Shetland

Moths are the members of the order Lepidoptera. they are close relatives of butterflies - indeed there is not really any scientific distinction between the two. In Shetland almost 300 species of Lepidoptera have been recorded so far. Species are being added to this list at regular intervals thanks to the activities of the Shetland Entomological Group. This page gives a brief overview of moths in the islands.

Below are the names of the major groupings of moths.

  • Swifts ... including the endemic Shetland Ghost Moth

  • miscellaneous Microlepidoptera ... some of the smaller and more inconspicuous moths

  • Tortrids ... another group of Microlepidoptera

  • Pyralids ... more of the smaller moths, including the grass moths

  • Geometers ... Carpets, Pugs and allies

  • Hawkmoths ... some of the largest and most spectacular of the moths

  • Tigers and Lymantrids ... a small but colourful group

  • Noctuids ... the largest group of moths, including most of the larger species

Photo above: Beautiful Golden Y Autographa pulchrina

Swifts Hepialidae

Only two species from this group are found in Shetland. They are both common species - the Map-winged Swift Hepialus fusconebulosa and the Ghost Moth Hepialus humuli. The Ghost Moth gets it's name from the white appearance of the male - however, in Shetland the male is yellow like the female, presumably because white males would be too obvious in the light Shetland nights. Because of their appearance Shetland Ghost Moths are separated as a subspecies - H. h. thulensis. The caterpillars of the swifts feed on roots and they probably take two years to become adults. Like several moths, the adults do not feed.

 

 

photos: left, Map-winged Swift Hepialus fusconebulosus and right, a male Shetland Ghost Moth Hepialus humuli thulensis

 

miscellaneous Microlepidoptera

The microlepidoptera form more than half of the moths found in Britain and they also include the next two groups, the Tortrids and the Pyralids. These latter groups are comparatively well-studied, however, whereas most of the rest of the micros are very much the realm of the specialist. Many species are hard to find as adults and few are more than 15mm long. Some have larvae which feed inside leaves or stems, hence they are known as leaf-miners.

Some of the more obvious members of this group are the Housemoths, present in most houses throughout Shetland. The smaller White-shouldered Housemoth Endrosis sarcitrella is the commoner of the two. The other species is the Brown Housemoth Hofmannophila pseudospretella, originally a colonist from South America.

The commonest of the resident species is the tiny Nettle-tap Anthophila fabriciana. The caterpillars of this species feed on nettle and the adults can be seen flying around clumps of the foodplant anywhere in the islands from mid July into August.

Not many of the smaller moths are migrants, but the Diamondback Moth Plutella xylostella is one of the most famous of all migrant moths. It occurs in Shetland every year, but in variable numbers. Occasionally, there are huge influxes of thousands of moths, as in early July 1994. The moth is unpopular as it is a pest of Brassica crops such as cabbage. In Shetland the garden plant Sweet Rocket Hesperis is also frequently used as a foodplant.

photo: Nettle-tap Anthophila fabriciana on it's foodplant, nettle

Tortrids

This is another group of small moths, rarely longer than 15mm. Almost 40 species have been recorded in Shetland, almost all of which are resident.

Many species are active by day, but they are easily overlooked because of their small size. Eana osseana is one of the commonest moths in Shetland. Along with one of the Pyralid moths it is the small moth kicked up from grassy areas throughout the islands, although it flies later and is commoner in August.

Some of the other common day-flying totrids include Syndemis musculana , found on moorland in June, Olethreutes lacunana which is another moorland species commonest in July, Bactra lancealana found in any damp, rushy areas in the summer. Eupoecilia angustana and Cydia succedana are both common around Birdsfoot Trefoil on Unst, but appear to scarcer elsewhere.

Other Tortrids are active by night, including the relatively large, grey Eana penziana and several species of Acleris, the commonest of which is the orange-brown Acleris aspersana.

Pyralids

These are the largest of the micromoths, some with wingspans of several centimetres. About 20 species have been recorded in Shetland, eight of which are migrants.

The commonest Pyralid, and probably the commonest moth in Shetland, is the grassmoth Agriphila straminella which can be extremely abundant in grassy areas in July. Another common and obvious species is Udea lutealis, a cream-coloured, Concorde-shaped species which is common in August. Eudonia angustea , a slender species, can be quite common at lighted windows in August.

Two other resident species are upland species in the rest of Britain. Eudonia alpina is found to sea-level in Shetland but is very scarce at low-level elsewhere in Britain. The distinctive orange-brown Catoptria furcatellus is very scarce anywhere in Britain and is only found in Shetland on the highest hill, Ronas Hill.

The commonest migrant is Rush Veneer Nomophila noctuella, recorded almost annually in variable numbers. The noted migrant Rusty-dot Pearl Udea ferrugalis has also turned up in the last couple of years. Other migrants are all very rare, including the only Scottish record of Thistle Ermine Myelois cribrella on Fair Isle in 1991, and one of a handful of Scottish records of Numonia advenella.

Geometers

This is a large group of moths, most of which rest with their wings either out flat or held together vertically over their back, rather like a butterfly. Several species are active by day. The larvae are also active by day and so are easily found. The caterpillars move with in characteristic fashion, as though they are measuring, leading to the popular name of "inchworm".

 The two commonest geometers in Shetland are both represented by distinct Shetland subspecies - the Red Carpet Xanthorhoe munitata hethlandica (illustrated on the Shetland Entomological Group home page) and the Silver-ground Carpet Xanthorhoe montanata shetlandica (illustrated above). The Red Carpet is very common in South Mainland but the Silver-ground Carpet appears to be commoner in the Northern Isles. It can often be found by day, often on moorland.

Another very common species is the Winter Moth Operophtera brumata . It is the only species to fly in mid-winter in Shetland, and it can be very common on mild December nights. The female of this species is flightless but caterpillars have been known to spread by "ballooning" - getting carried on air currents on silk spinnings in the same way as spiders. The green larvae are common on trees and heather in summer, and they can be a significant pest. Another pest of trees, usually willows, is the July Highflier Hydriomena furcata. It flies in August in Shetland, incidentally!

 There are several other common resident species. On the hills and moorland the Chevron Eulithis testata and the Northern Spinach Eulithis populata are both common, as is the tiny Satyr Pug Eupithecia satyrata . The Netted Pug Eupithecia venosata is common around suitable beaches. Around crofting land the Garden Carpet Xanthorhoe fluctuata , the Grass Rivulet Perizoma albulata and the Twin-spot Carpet Perizoma didymata are all common. Many of these species occur in local forms (not always comprising the entire population. This is probably because Geometers are not famous migrants so the isolated populations in Shetland have developed their own characters.

One or two Geometers do migrate and have turned up in Shetland. these include the Gem Orthanoma obstipata , a well-known long distance migrant, and species such as Bordered White Bupalus piniaria and the Magpie Moth Abraxas grossulariata which have probably just wandered from the established populations on the British Mainland.

photos: left to right - Magpie Moth Abraxas grossulariata, Chevron Eulithis testata (top right) and Garden Carpet Xanthorhoe fluctuata

Hawkmoths

These are some of the largest moths in Britain and many species are strong flyers and long distance migrants. In Shetland the commonest species is the Convolvulus Hawkmoth Agrius convolvuli which is recorded annually in small numbers. The Bedstraw Hawkmoth Hyles gallii , the Hummingbird Hawkmoth Macroglossum stellaturum and the Death's Head Hawkmoth Acherontia atropos have all been recorded in the islands, each on fewer than 20 occasions. The Privet Hawkmoth Sphinx ligustri and the Striped Hawkmoth Hyles lineata have only been recorded once each.

photo: Hummingbird Hawkmoth Macroglossum stellaturum

Tigers and Lymantrids

Only one species in this group is resident in the islands - the inaccurately named Wood Tiger Parasemia plantaginis is reasonably widespread on moorland on Mainland and Foula. The Garden Tiger Arctia caja has occurred once as a vagrant and singles records of the Lymantrids White Satin Moth Leucoma salicis and the Vapourer Orygia antiqua presumably also refer to wandering or vagrant individuals.

Noctuids

The Noctuids are a huge group of moths which includes some very common resident species as well as some prominent migrants.

The commonest noctuid moths in Shetland are the Hebrew Character Orthosia gothica which flies in April, the Shears Hada plebeja which flies in May to June, the Clouded-bordered Brindle Apamea crenata which flies in June to July, the Dark Arches Apamea monoglypha which flies in July to August and the Antler Cerapteryx graminis which flies a little later in the same months.  

Some nationally rare moths are resident in Shetland. The Exile Apamea zeta marmorata was originally described as a new species to science, but is now placed with the Scandinavian subspecies of a widespread sub-polar species. The Northern Dart and the Broad-bordered White Underwing Anarta melanopa were both apparently common last century, but are rare now.

In the autumn there are several fairly common moths including the Autumnal Rustic Paradiarsia glareosa, the Square-spot Rustic Xestia xanthographa and the Brindled Ochre Dasypolia templi. Other common moths in autumn, such as the Brick Agrochola circellaris, the Satellite Eupsilia transversa and the Angle Shades Phlogophora meticulosa are probably short-distance migrants from Britain or the near Continent.

Several long-distance migrants are common in Shetland, most obviously the Silver Y Autographa gamma, which turned up in tens, if not hundreds of of millions in August 1996.

The Dark Sword Grass Agrotis ipsilon, is another annual long-distance migrant but Shetland is also a very good place for rarer migrants from Scandinavia. There is no better place in Britain to see migrant Great Brocades Eurois occulta, from Scandinavia.

Even rarer moths also turn up with national rarities such as the Clifden Non-pareil Catocala fraxini or the Scarce Bordered Straw Heliothis armigera. In 1996 two extreme rarities were recorded - Dewick's Plusia Macdunnoughia confusa with fewer than 30 British records and the seventh and eight British records of Scarce Brindle Apamea lateritia.

 

 

photos: top to bottom - Silver Y Autographa gamma, Square Spot Rustic Xestia xanthographa, Satellite Eupsilia transversa, and Dark Arches Apamea monoglypha

 

This site is not directly connected to any of the organisations mentioned, so comments  may not necessarily reflect the views of the organisations, clubs or societies  involved. The pages on this website remain the intellectual property of the authors. They may be freely downloaded, quoted or used for any purpose, providing acknowledgement is given to the website and/or the author/s. No liability is accepted for the accuracy of this information.