Glasgow & SW Scotland Butterflies

Glasgow & SW Scotland Branch Website

February 7, 2010

Narrow-bordered Bee Hawk-moth Surveys in Argyll 2010

Filed under: Moths — Tags: , — Andrew Masterman @ 3:29 pm

Narrow-bordered Bee Hawk-moth  (Hemaris tityus) has 50 Argyll records relating to 24 sites mostly in north Argyll but there is one much further south for the southern tip of Bute in 1960.  It is also found in some other parts of Scotland including the Cairngorms, Moray, Easter Ross and Wester Ross. The map below shows all the records of Narrow-bordered Bee Hawk-moth (NBBHM) in Vice County 98 relating to the northern part of the Glasgow and SW Scotland branch of Butterfly Conservation area.

Distribution of NBBHM in VC98

Distribution of NBBHM in VC98

NBBHM is an amazing day-flying moth with a body length of about 2 cm and a total wing span of about 4-4.5 cm - so a large and spectacular moth!  It is on the wing from mid-May to early July in the same areas as the beautiful Marsh Fritillary. This is no co-incidence as they both have the same foodplant, Devil’s Bit Scabious and the same flight period so it is possible to see both these rare species of Lepidoptera at the same site on the same day!

Narrow-bordered Bee Hawk-moth   Credit: Phil Holt

Narrow-bordered Bee Hawk-moth Credit: Phil Holt

NBBHM is not the easiest of moths to identify in the field for two reasons.

  1. NBBHM does not look like a moth -  NBBHM has transparent wings and therefore looks like a large bumble bee (it is a very convincing bumble-bee mimic) but you can distinguish it from bumble bees because it does not fly like a bumble bee and it doesn’t buzz. Bumble-bees have an erratic zig-zag flight and are noisy too! NBBH tend to fly in straight lines and they have a large buff-coloured backside which is conspicuous and diagnostic. There are also insects known as bee-flies (Bombylius spp) but these are smaller than NBBHM and not as spectacular.
  2. NBBHM flies fast - this characteristic means you may only get a fleeting glimpse of an insect which looks like a bee but there is something un-bee-like about it. But this leaves you uncertain about whether or not you have indeed seen a NBBHM. As this is a UK BAP species, it is important that you are confident of your identication before you submit a record to the VC moth recorder. But NBBHM does like to nectar and this behaviour enables you to get a much better look at it to be sure of an identification. It nectars while hovering unlike bees which land to feed but in cooler cloudier conditions, you might see it at rest on nectaring plants.

The preferred nectaring plants of NBBHM are louseworts, bugle, viper’s bugloss, common bird’s foot trefoil, rhodedendron and red valerian. Apparently, you can lure it to a sprig of lilac which you could take with you into the field!

NBBHM only flies in warm sunshine so you do need good weather to see it. The habitat of NBBHM and Marsh Fritillary is low lying flat  damp grassland, sometimes a more heathy type habitat,  with abundant Devil’s Bit Scabious but the bottom of slopes which also tend to be damp may also provide good habitat. A couple of examples are shown below:

Grazed damp grassland

Grazed damp grassland

 

Marshy Heathy type habitat

Marshy Heathy type habitat

 

There are several areas in North Argyll where there are a number of historical records of NBBHM and branch members are encouraged to visit these areas to see this spectacular UK BAP moth, to recognise its habitat and to look for it in other nearby sites or other sites in Argyll.

One such area is Taynuilt where an open area known as the common grazings has patches of marshy habitat with abundant Devil’s Bit Scabious where NBBHM may be found and Marsh Fritillary can also be seen in low numbers. The red spot in the south-west of the map below (NM986307) which is just before the road goes into an area with houses (Balindore)  is a great spot to see NBBHM and Marsh Fitillary in a marshy area just to the east of the road (the red spot is on the wrong side of the road!).

NBBH Sites around Taynuilt

NBBH Sites around Taynuilt

 

Around Glen Creran is another good area with many NBBHM records with the Appin Peninsular being a hot spot and there may well be other sites to be discovered in the Appin peninsular.

NBBHM sites around Loch Creran

NBBHM sites around Loch Creran

 

There are also a number of NBBHM records for the Isle of Lismore just to the west of the Appin Peninsular. There is a passenger ferry from Port Appin which takes just 10 minutes enabling you to bring a bicycle if you wish and a car ferry from Oban taking 1 hour. See Lismore Ferry for more details.

NBBHM sites on Lismore

NBBHM sites on Lismore

 

There are a few scattered NBBHM records around Oban which suggests that it is under-recorded here so searching in the area between Oban and Loch Feochan may well result in the discovery of some new sites. There is also one record on the Isle of Kerrera  just to the west of Oban which is a short passenger ferry trip from south of Oban.

NBBHM sites around Oban

NBBHM sites around Oban

 

Any NBHHM records in Argyll VC 98 should be sent to andrewmasterman@hotmail.com. Records from other vice-counties should be sent to the appropriate recorder whose contact details can be found on the Mothscount website.

The above maps and the grid-references of the historical records can be found in this word document which you can print out.

There is a Butterfly Conservation leaflet on NBBHM (PDF 540 kb) available which provides more information on the lifectcycle of this amazing moth.

Andrew Masterman
VC98 Moth Recorder

Moth Records for VC98 Argyll Main

Filed under: Moths — Tags: , , — Andrew Masterman @ 11:04 am

Vice County 98 covers Argyll south of Loch Leven and north of the Crinan Canal near Lochgilphead, the Cowal peninsular and Glencoe, most of Rannoch Moor and the islands of Lismore and Kerrera.

As of February 2010, there are 22958 Macro-moth records in the VC98 database relating to 331 species. Eighty-six per cent of these records relate to the Glencoe Rothamsted trap at the National Trust for Scotland visitor centre. The Rothamsted Light Trap at Glencoe is part of a UK wide network of 80 traps run by the Rothamsted Insect Survey since 1968.  The Glencoe trap has been in operation since 1996 and the addition of the data from this trap added many new species to the VC98 database. There were 62 new species which are classified as common species. There were a further 28 species which have much more local distributions and are interesting records.

As of February 2010, there are 191 Micro-moth records in the VC98 database relating to 62 species.

Six UK BAP Macro-moth species are present in the VC98 database.

Barred Tooth-striped  (Trichopteryx polycommata) has 27 records relating to five sites in north Argyll. This moth has very localised scattered distributions in Scotland and England with the majority of Scottish records in Argyll.  It flies early in the year in March April and comes to light traps. The larvae feed on Ash or Privet and it overwinters as a pupa. In Argyll, it has been recorded at Creagan Wood and Glasdrum NNR on the north side of Loch Creran, on the south side of Loch Creran at Barcaldine and also at Glen Nant NNR. There is also one record at the Glencoe RIS trap. These are all deciduous woodland sites but in southern England, it is associated with open scrub on chalk downs and with some limestone sites south of Cumbria.

Barred Toothed-striped

Barred Toothed-striped

Argent and Sable  (Rheumaptera hastata) has 16 records relating to 12 sites in north and central Argyll. This is a day-flying moth on the wing in May and June and the caterpillars feed on bog myrtle and birch and it overwinters as a pupa. There are three sub-species in the UK with hastata hastata occurring in England and southern Scotland as far north as southern Argyll, a smaller and darker form,  f. nigrescens found in the Hebrides and the far NW of Scotland and a third sub-spp hastata f. laxata which occurs in Argyll and other parts of the southern Highlands.

 

Argent & Sable   Credit: John Knowler

Argent & Sable Credit: John Knowler

Square-spotted Clay  (Xestia rhomboidea) is an ex-UK BAP species and has 15 records relating to 4 sites in north and west Argyll. This is a rare species in Scotland with most records from Argyll although it is much more common in southern England. If flies in late July and August and comes to light. There is some uncertainty about which plants the caterpillars feed on but birch and bramble are likely examples of a range of plants which can be used. It overwinters as a small caterpillar. The habitat is deciduous woodland and in Argyll, it has been recorded at Glasdrum Wood and Glasdrum NNR, Glen Nant NNR and Taynish NNR all of which have mature decidious woodland and also around the Loch Melfort area.

Square-spotted Clay

Square-spotted Clay

 

Forester (Adscita statices) has 22 records relating to 8 sites on the west coast of Argyll. It is a day-flying moth which is a joy to see with its bright emerald shiny wings. Its caterpillars feed on Common Sorrel and Sheep’s Sorrel and its habitat in Scotland is sunny sheltered  areas with some bracken in coastal parts of Argyll.

Forester

Forester

 

Narrow-bordered Bee Hawk-moth  (Hemaris tityus) has 50 records relating to 24 sites mostly in north Argyll but there is one for the southern tip of Bute in the south of Argyll. This is an amazing day-flying moth found during late May and June in the same areas as Marsh Fritillary. This is no co-incidence as they both have the same foodplant, Devil’s Bit Scabious and the same flight period so it is possible to see both these rare species of Lepidoptera at the same site on the same day! The habitat of both these species is low lying flat  damp grassland, sometimes a more heathy type habitat,  with abundant Devil’s Bit Scabious but the bottom of slopes which also tend to be damp may also provide good habitat.

Narrow-bordered Bee Hawk-moth     Credit: Phil Holt

Narrow-bordered Bee Hawk-moth Credit: Phil Holt

 

Transparent Burnet (Zygaena purpuralis) has 25 records relating to six sites near Oban. The strongholds of this amazing moth are the Hebridean islands of Mull, Skye, Ulva, Eigg, Canna, and Rhum and the only records on the mainland are around Oban and also in parts of Kintyre. It was seen on the islands of Kerrera and Lismore in 1960 but there are no recent records. The adults are day-flying in warm sunshine from early June to July and the caterpillars feed on wild thyme. It overwinters as a caterpillar. Its habitat is steep, heathy and grassy south and south-west facing slopes and under-cliffs near the coast.

 

Transparent Burnet    Credit:  Neil Gregory

Transparent Burnet Credit: Neil Gregory

Andrew Masterman
VC98 Moth Recorder

January 5, 2009

Conservation of the Dingy Skipper butterfly in South West Scotland

The Dingy Skipper (Erynnis tages) is currently the rarest of the 34 butterfly species found in South West Scotland. The adults are small and well camouflaged with grey and brown wings and can easily be mistaken for a moth. (See Dingy Skipper species information page for more details). In the last few decades it has suffered a severe decline throughout the UK and is now classed as a national BAP priority species.  The reasons for this decline are not entirely clear as the food plant Bird’s-foot trefoil (lotus corniculatus) is pretty widespread, however it appears that female dingy skippers are very selective in where they lay their eggs!

Dingy Skipper on bird's-foot trefoil. Keith Warmington

Dingy Skipper on Birds foot trefoil by Keith Warmington

 

 

 

 

 

Changes in land use, such as agricultural intensification, the cessation of coppicing in woodlands, habitat succession, and the recent policy of developing brownfield sites appear to be major factors in the loss of this species. Adults also tend to be quite sedentary and are unlikely to move to new suitable habitat unless it is very close by. Larger colonies are more likely to produce exploratory individuals that could initiate a new colony.

Ideal habitat conditions occur where bird’s-foot trefoil (or occasionally greater bird’s-foot trefoil) is found in warm sheltered sites with sparse sward/grass covering and plenty of bare patches for basking in the sun. Patches of taller vegetation or light scrub may be used by the adults as roosting sites. In south west Scotland the Dingy Skipper has been recorded at a few sites along the south coast of Dumfries and Galloway; in small numbers on the Ayrshire coast south of Girvin and also at a few inland sites such as the Butterfly conservation reserve at Mabie forest. A colony at the SWT Feoch meadows reserve was only discovered in 2008, and so other potential sites may be awaiting discovery.

It is hoped that further local colonies can be identified and protected before it is too late. In order to conserve the species we first need to know its current distribution and the size of existing colonies. At some sites only one to two individuals have been seen, so it is important to confirm that theses sites contain breeding colonies rather than just vagrants passing through. For detailed conservation planning and action to take place it is important to identify where on these sites the dingy skipper is breeding. Once this is known, the breeding areas can be preserved and hopefully enhanced by appropriate management or habitat creation.

I believe that most of the recent sightings in south west Scotland have been of individuals or small numbers of adults. Does anyone know of large colonies? Are these individuals part of small fragmented colonies, or perhaps vagrants from larger colonies existing undetected nearby? The low number of sighting haven’t been helped by the poor weather conditions we have had during 2007 and 2008 combined with the relatively small number of people who would know what they were looking at if they did see one!

To confirm breeding at a site where adults have been seen it is possible to search for dingy skipper eggs on bird’s-foot trefoil. This is best done after the peak flight period of the adults, and importantly can even be done on overcast days when adults wouldn’t normally be seen. In south west Scotland the peak adult flight period is normally around the first week of June, so eggs will be visible during the following 2 weeks before they hatch. The female lays her eggs singly on the upper surface of leaves on fresh shoots, normally within a 2.5 cm of the shoot tip. Occasionally more than one egg will be found. The eggs are round and greenish-white when first laid and can be quite difficult to see, but later (after about 5 days) turn a bright orange which should be easier to see (unless like me you are red-green colour blind!). The female generally chooses shoots growing away from the main plant especially those spreading over bare ground or rocks. Rocks and bare ground will absorb and hold more warmth than surrounding vegetation, which may enhance development of the egg and larvae. Plants in sheltered hollows will be chosen over exposed plants.

Dingy skipper egg. Keith Warmington

Dingy skipper egg. Keith Warmington

When searching for eggs, look for areas of the site with bird’s-foot trefoil. Walk in rows about 1m apart back and forth, stopping if you find a plant with tendrils growing over bare ground or path. Shoots growing over dry dead fescue grasses (small fine bladed grasses) may also be used, especially if in a dip or hollow. Its only worth searching hollows were the food plant is sheltered, but not shaded by surrounding vegetation. It’s no use searching areas where the vegetation is higher than 15cm. If you find a likely spot, bend forward so your head is parallel with the plant and you will hopefully be able to see an egg. Once you’ve seen one, you should be able to spot others more rapidly. If you find eggs on a plant in a hollow or bare patch, search others nearby as other females may also have taken a fancy that location. The caterpillar is green with a dark green stripe down its back and a dark head. They tend to be more difficult to see as they form a tent of leaves and silk to hide in.

Any records of adults, eggs and the rather shy green larvae would be very welcome (butterfly records page). If you can get a photograph of the site and particularly the location where eggs were seen, or even just a description, this could proved very valuable information for the protection of the site and the conservation of this endangered species. It would be useful to know if any adults were seen at the site, if multiple eggs were found on the same plant, the colour of the eggs (indicating how recently they had been laid), the height of surrounding vegetation, were there any signs that the site was grazed (cow pats? Tufts of wool? Rampaging bulls?) or maintained by mowing?.

Much of the egg hunting advice above was taken from a fantastic article by Mike Slater in the February 2008 edition of the Warwickshire butterfly conservation newsletter.

I hope this is useful information for anyone who’d like to get out and search for this charming and often overlooked little butterfly. Please feel free to leave a comment below, or information on any of your sightings and locations.

Written by Scott Shanks.

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