Glyn-Coch Studios Logo. A Norfolk Horn Ewe over text Glyn-Coch Studios

Glyn-Coch Studios

Glyn-Coch wildlife monitoring

Picture taken at Glyn-Coch Farm


Glyn-Coch Farm looks like a good ecological site with contrast in soil, height, drainage, woodland, grassland, ponds, ditches, and with the main railway line from London to the Irish ferry ports etc. on the border. It is surrounded by farms where mainly permanent pasture is surrounded by traditional hedges in a landscape with many small woods and is about 2 miles from wet fields at the head of the Taf Estuary

Ecological monitoring

is carried out, which includes informal species lists, RSPB Farmer and volunteer survey, and we have entered several competions with ecology as an important factor, and we run a Rothamsted Insect Survey Light Trap. Data we collect also goes to the County Moth Recorder, Bat Conservation Trust, and the local branch of National Biological Network

Competition table

Note: While not always involving ecological monitoring themselves, these competitions provide an incentive to bring to gether the informal lists, check identifications etc. Not only is ecology interesteing to us, but is also interesting to the organisations that run, or sponsor these competitions.
The "Farming Link Survey" was about economics, not ecology, but an important factor in our success was our very small investment in machinery and farm inputs. The fact that many jobs are done by hand instead of machinery, allows widlife to escape in front of us as we work across a field or down a hedge or ditch, and we do not smooth out variations of slope etc with wide machines. Weed control by strict rotational grazing and topping also allows species that are not economically damaging to survive in our permanent pasture.

About Rothamsted Insect survey Farm Light Trap Network

The Rothamsted Insect Survey operates two national networks for monitoring insect populations in the UK. The light trap network, run with the help of volunteers at about 80 sites in the UK, is used to monitor the larger (macro) moths. Daily samples are taken throughout the year, and altogether over 430 sites have been sampled. The earliest moth records date back to 1933 from a trap on Rothamsted Farm and a national network was in full operation by 1968. Rothamsted

St Clears Trap summary

The table below shows the a-diversity index recorded for our trap in the years for which it has been running. (A-diversity index gives an indication of the number of species recorded in each year. The rank is from a table of the 20 most diverse traps (out of a total of between 80 and 100 traps) in each year. Note that having a higher diversity is no guarantee of being in the top 20 table, as other traps may do even better. In 2004 there was an unplanned change of identifier, meaning that our catch had to be added on to someone else's extremely heavy work load. By the time our catches were high enough up the queue to be identified they had deteriorated to such an extent that they were abandoned. In 2008 we did not make the "Top 20 diversity table", but the lowest trap that did had a score of 37.88.

Year a-index diversity Rank
2002 38.98 19
2003 37.864
2004 lost data
2005 38.57
2006 43.27 17
2007 40.814 18
2008 <37.88
2009 37.103 -
2010 38.571
2015 39.3 13

Rothamsted Insect Survey "Trap of the Month" June 2017

Glyn-Coch Studios light trapFig. 1: Trap 592. St ClearsGlyn-Coch Studios light trapFig. 2: St Clears trap location & surroundings.

Trap 592.St Clears (Fig. 1) came into operation in 2002 on the smallholding of former Rothamsted Insect Survey member Huw Jones. Glyn-Coch Farm is set in fairly typical Welsh lowland pastureland to the NW of St Clears, Carmarthenshire (Fig. 2). Bounded to the north by the railway which acts as a natural corridor, the farm has extensive plantings of native trees (plus some American black cherries) and is primarily farmed for sheep (the only Norfolk Horn flock in Wales) with a few chickens & geese. Despite the continuing conservation efforts made at the farm (It has received and been on the shortlist for a variety of conservation orientated awards over the years) the general population numbers are unremittingly down (Fig. 3), with two incredibly poor years in 2004 & 2014. Leaving those years aside it is still clear that numbers have dropped from ca. 7-8000 moths per year to 5-6,000. A creditable 354 species have been recorded (see attached species list) with a generous smattering of uncommon migrants augmenting the local species.
Glyn-Coch Studios light trap
Fig. 3: Total numbers of moths at St Clears 2002 to 2015.

The now traditional “two-up, two-down” graphs have been a struggle to assemble this month, it appears that at St Clears there are many losers to select from and few winners. This has, of course, been the general case across all the Trap of the Months so far but the situation appears more stark at St Clears which is clearly a concern given the general management of the site has been with a (award winning) conservation bent. A quick glance upwards will show that diversity remains high and (spoiler alert) St Clears has appeared in the top 20 traps in the network for alpha diversity in most years in spite of the general decline in total numbers. Two species that are doing well are the Ingrailed Clay (Diarsia mendica) and the Chestnut (Conistra vaccinia) (Fig. 4) in contrast two species that surprised me by the extent of their declines are the Hebrew character (Orthosia gothica) and the Beaded Chestnut (Agrochola lychnidis) (Fig. 5) the latter of which has dropped from three-figure catches in the early years of the trap to virtually zero in recent times.

Numbers of Ingrailed ClayNumbers of Chestnut Moths Fig. 4: Two increasing species at St Clears

Numbers of Hebrew CharacterNumbers of Chestnut Moths Fig. 5: Two declining species at St Clears

You can download more catch data about other species here

To see the full species list look here

More thoughts: -

After we were chosen as "Trap of the Month in 2017, I was asked if I had any idea about factors that may have cause the decline inspecies numbers. What follows are some of my anwers.

Blog (2013)

Four years ago I started a blog about the daily moth collections that I make as a volunteer with the Rothamsted Insect Survey. (Pictures are missing from this archived version, but I will start adding them if there is a demand.) Apart from a sense of excitement about what the next catch may bring, I hope that you will also get the message that, while being of international importance, a project that helps to drive Government policy throughout the world, it is actually a very poorly funded project depending on the voluntary efforts of a number of expert identifiers, who must devote many tens of hours a week to this project. (In spite of having spent 6 years identifying all the moths from 20 traps as a full time job (with two authors of respected moth identification books looking over my shoulder!), I would not consider myself anywhere near as skilfull as the wonderful people on whom we trap operators rely.)

24th June 2013: Moths

People tell me that moths are boring little brown things that spoil summer evenings by bumbling about the house, and they can't understand the fascination that some people have with them. Peach Blossom Moth Green Carpet Moth Peppered Moth

I hope that these pictures will at least prove that moths are not all brown and boring. The first picture is of Peach Blossom moths, the second is a Green Carpet and the third is a Peppered moth. These are just some of maybe 20 moths that we caught a couple of days ago and though not all were as colourful as these they were all interesting and important in their own way. The three species in the pictures are all fairly common, and you should not get too excited about the names they have. We do not grow peaches at Glyn-Coch, but we do have quite a lot of brambles, which is what Peach Blossom moths feed on, so Peach Blossom moths are quite common all over the UK. The name arises because their appearance reminded the first person to describe the species of Peach Blossom.

The colours of moths' wings either comes from microscopic ridges on the surface of the scales, which cloak the wings, and scatter the light so that you see different colours depending on the size (frequency) of the ridges, or alternatively the colour comes from pigments. We are very lucky to have caught a green Green Carpet moth, because the green is a pigment, and this fades very rapidly once the moth emerges from its pupa, so usually you have to identify a black and white moth from the pattern alone. Green Carpet moths feed on "bedstraws", of which the most common is "Goosegrass" also known as "cleavers", so if you are a gardner you may like to have a few Green Carpet moths around.

The Peppered moth is the species you may have learned about at school in which there are different colour forms, One is black (called melanic) and another form is the white (or normal) form which we have here. In Victorian times and up to the mid 20th century the melanic form was the common form in industrial areas, because the soot that covered everything meant that birds could easily find the white moths, while the black ones merged with the background. At Glyn-Coch the air is so clean that the white moths (helped no doubt by the black "pepper" spots) merge with the background, and the melanic moths are more easily caught by birds and other predators.

But we do not catch moths just for fun. We catch them in a special Light Trap as part of the Rothamsted Insect Suvey, which you can read about on their website. Rothamsted

While network data has been used to study statistical methods relating to population studies, and even by mathematicians investigating such things as "strings" and "chaos", the original purpose of the survey was to check methods used in pest forecasting schemes to helpe farmers move away from routine spraying to the use of sprays only when dangerous pest populations had actually built up. (This reduced the impact of pesticides on the environment while at the same time increasing quantity and quality of food in the shops, and reducing the price.) Since then the survey has been used to check the geographical distribution, and flight periods of moths and other insects, and in the course of this work it was discoverd that that global warming was really affecting real species of wildlife. Recently Scientists from Butterfly Conservation and The Centre for Hydrology and Ecology amongst others have been using Survey data in their studies on climate change, and the decline of insect species. In future, the survey will become increasingly important as a means to monitor the arrival of new pest species as they move to higher latitudes in response to climate change. This knowledge will help protect not only crops, but also endangered species of wildlife, which may have no defence against the novel pests.

The trap that the Survey uses is of a unique design and can be used for continuous monitoring of the local moth population in the same place over very long periods of time. (It has been show that Rothamsted traps can be placed 10 metres apart without reducing the spiecies diversity or abundance caught in each tap. Traps of this type were first used nearly 100 years ago.) Some traps in the Rothamsted Insect Survey have been running for over 50 years, so the team at Rothamsted can see exactly how populations are changing over time. The Glyn-Coch trap was installed in 2000, and we have caught over 230 species, and have been in the top 20 sites in the country in 3 years since then. The trees in our woodland were only planted 4 years before we started trapping moths and most of the trees were still only a couple of feet tall. Now some of those young trees are over 50 ft tall, so we hope to see how new woodland species have replaced the grassland species that were here before. As moths usually only feed on one or two species of plants, the presence of a particular moth species in a catch may prompt us to look for its food plant in the woodland.

27th June 2013:More Beautiful Moths

The moths pictured below were caught in our Rothamsted trap at Glyn-Coch. (See entry for 24th July for more information)

Blood Vein

The Blood Vein Moth (above) feeds on weeds, such as Docks, Common Orache, Common Sorrel, Knotgrass and probably their relatives. With such common food plants it is able to produce up to three generations a year, flying in May to early July, July to September and sometimes a third generation in September and October. As you can imagine deciding that moths flying later in July were of a different generation to those flying a few days earlier was quite difficult, and the continuous monitoring made possible by the Rothamsted traps was a considerable help in resolving this sort of problem. Why bother? You may well ask. Well moths like the Blood Vein may be thought of as beneficial insects as they help to control weeds, and understanding their habits helps us to devise weed control strategies that work while minimizing the damage we do to our allies like the beautiful Blood Vein moth.

Clouded Border moth

The Clouded Border moth (above) flies as early as May in the south of Britain, but mainly in June and July, with occasional individuals of a second generation flying in the Autumn. The Rothamsted Light Trap Network should be able to pick up the affects of global warming on this species, with perhaps the boundary of May flying moths moving northwards, and greater numbers of the autumn generation. However, we may also see the moth becoming scarce in the south as the climate becomes too hot or dry for it. Clouded border moths feed on trees such aspen, poplar, sallow, and willow. It is one of the species that should become more common at Glyn-Coch as these species of tree become established and mature.

2nd July 2013:Even More Beautiful Moths

One of the advantages of a late cold spring, if you are a moth-er is that you often get short periods, later, when all the species that have been delayed by the cold weather are trying catch up. Most species have only a short period, typically less then a month, as flying adult moths. When the seasons, as this year, are compressed then the adult moths are even more frantic to get their mating and dispersal over. The caterpillars of many species pupate on their food plants, and if those plants are shrubs or trees then once they emerge from their pupae the females tend to stay put and mate and lay their eggs on the same tree that they grew up on. The males are the ones who tend to fly away from the pupation site, and look for females in other areas to mate with. Most of the moths caught in light traps are males on the way to find new colonies. Normally, by the time they are caught they have spent some time exploring, and are quite battered, but in these frantic catch up periods quite new moths get caught. This is why I am getting so excited now. ScallopShell moth

The other day we caught two species that I do not recall having identified before, certainly not recently, and I think that you will agree that the Scallop Shell (above) is a beautiful creature in spite of its general brown colour. The adults fly in June and July and sometimes fly in daylight, which no doubt adds to the confusion between moths and butterflies! The larvae feed on Sallow, Aspen or Bilberry (or perhaps poplar here, given the proximity of poplars to the trap) in August and September before pupating and spending the winter in the soil. In a cold spring, perhaps it is an advantage to pupate underground, away from the cold!

Coronet Moth The above moth is, I think, a Coronet, though I must confess to complete ignorance of this species. It could just be a Poplar Grey from its markings, but its general body shape is wrong. But apart from my ignorance, there is another problem, and that is that this is one of those battered specimens I mentioned, and as the scales get knocked off, so the pattern is less distinct, and one is misled by the underlying veins in the wings. There are a few other species that have a likeness to this specimen as well, but I will stick my neck out and go for a Coronet. (Lets hope that Barry, with his very considerable expertise, who does the formal identification agrees with me!) The Coronet has a similar life cycle to the Scallop Shell, but the larvae feed on Ash, (Wild Privet), Alder and Hazel and then pupate in a strong cocoon under moss on a tree trunk.

4th July 2013: "Precious" Moths

As I have said, you don't need to take too much notice of the common names of moths, but when these three arrived in the same catch it was just too good to miss. Green Silver Lines

The Green Silver Lines moth

Feeds on Oak, Birch or Beech, but also Hazel, Chestnut, Aspen, and Elms. Overwinters as pupa under a leaf or in bark crevice.

Plain Golden Y

The Plain Golden Y moth

Feeds on Nettles, White and Red dead nettles, Hogweed, Honeysuckle, Hawthorn and Sallows. Overwinters as small caterpillar in leaf litter.

Light Emerald

The Light Emerald

The larvae (caterpillars) feed on a wide range of broadleaved trees and shrubs including oak, hawthorn, blackthorn, hazel, birches, elms sallows, chestnuts and beech. It overwinters on the food plant as a small caterpillar

In spite of their "precious" names, all these species are fairly common, and anyone watching moths in warm weather round an outside light in the vicinity of the food plants would be able to see these in most parts of the UK at this time of year.

9th July 2013: Common Emerald Moth

Common Emerald

As I said, you do not need to take too much notice of the common names of moths. Although this species is usually common, it has been late arriving this year, and has been, unusually, less common then the light emerald so far. The species is also notable for its darker colour then most of the other Emeralds that you are most likely to see. Its larvae feed on most wild and cultivated broadleaved trees, shrubs and "exotic woody plants", and it over winters as a small caterpillar

11th July 2013: Poplar Hawk Moth

Poplar Hawk moth

Poplar Hawk moths are one of the largest species of moth that we regularly catch. The mainly gray colour of their forewings provides good camouflage providing that they keep still, and this species can stay still for a very long time. One specimen stayed in exactly the same place on the outside of the glass of a trap I was operating for a fortnight. By that time I had got quite attached to it and was afraid that one day I would find it in the trap. But on the 14th day it had gone, and there was no sign of it in the trap, and no sign that a bird had taken it. My relief that it had apparently escaped to safety, was increased by this demonstration of the environmental sensitivity of the Rothamsted trap. Moths can escape from the trap even in these circumstances.

When a Poplar Hawk moth is disturbed it can suddenly reveal its orange/brown hind wings, and the sudden flash of colour will scare off most moth predators. Insects that are poisonous are often brightly coloured and a quick flash of a reddish colour like the poplar hawk hindwings will also "put doubt into the minds" of some predators Poplar Hawkmoth caterpillars feed on all species of Poplar tree, and also sallows and willows. They over winter as pupae underground.

Tipulid parasite

Sometimes when you open a moth trap you find something you did not expect. The above picture shows an ordinary tipulid (Cranefly or Daddy Longlegs) which has been (I think) attacked by a parasite. The red "raspberry" growing out of its head is colony of cells each containing a tiny parasitic wasp. (Or so it appeared under a hand lens). I have tried to find out more about this, but without success, so far.

13th July 2013: Cinnabar Moth

Cinnabar Moth

The caterpillars of this spectacular moth feed on Ragwort, the yellow flowered plant which is poisonous to horses. I remember a time, back in the 1960s when fields next to my school were full of ragwort, and in midsummer the air was full of cinnabar moths. Catching them was a huge temptation and for a week or so most of us had red hands due to the bright red scales which are shed when you handle the moths. The bright red is a signal to predators that these moths have extracted a poison from the ragwort plant, and if we had eaten the moths we would have suffered liver failure, just as the horses would do if they ate ragwort. I have seen advice that children should not be allowed to handle Cinnabar moths for this reason. Another case of "health and safety gone mad", unless, of course, your child is given to eating moths! (I am interested in them, but think I am being brave handling them. Eating them ughh! )

The drinker

This beautiful moth is called a Drinker. The name comes from the habbit of this species to gather around the edge of puddles.

Drinker showing antennae

This male Drinker is displaying his huge fan like antennae. Just imagine flying while pushing that aerodynamic monstrosity along. In nature nothing happens without a reason, and the function of the antennae is to detect the pheromone (scent) released by the female. Moth antennae are very sensitive, and it is said that they can detect a single molecule of pheromone. But a single molecule only tells the male that a female exists somewhere nearby. The male needs to know which direction to fly in to find her, and how far he has to fly. To get this information, the more molecules he can detect the better, hence the enormous antennae.

Burnished Brass

This very shiny moth is a Burnished Brass moth. The metallic finish is another illusion caused by surface characteristics of the scales. It feeds on nettles (including dead-nettles, and consequently occurrs almost everywhere. Picture BuffArches

Buff Arches Feeds on Brambles and related plants, overwinters underground.

14th July 2013: Long Distance Plague Moths

SIlver Y Moth

The Silver Y is one of those dirty little brown moths you expected to see on this page, but it is a very interesting species nevertheless. This specimen was caught in mid July so it is almost certain that it is only a few days old. Its mother was a rather special moth. Almost certainly she emerged from her pupa thousands of miles away in the Canary Isles. She then flew up into a forming thunder cloud and drifted in freezing conditions near the top of the cloud across the Atlantic until the cloud rose over our coast and the storm broke. She literally arrived here on a shower of rain in mid to late June. Having arrived the moths breed like mad and produce about three generations before early autumn when the press start reporting a plague of green caterpillars eating everything in site. As the air temperature falls this frantic activity slows, and it used to be thought that the moths died, although in some years a few were seen to fly south.

Although this plague is spectacular it happens too late in most years and is over too soon to do serious damage to most crops, though the anxiety it causes is real enough. One of the climate change predictions, though, is that moths like the Silver Y will be able to survive in warmer winters, breed all year, and then become a scarily damaging pest.
The southward migration of Silver Y moths remained a mystery until colleagues at Rothamsted Insect Survey started experimenting with upward looking radar. Back in the 90s I used to supply moths caught in light traps to Jason Chapman, (who you may have seen on Bill Turnbull's excellent BBC2 Horizon programme on the decline of Bees) so that he could calibrate the radar. Jason and his colleagues were able to show that in the Autumn the British Silver Y moths flew up to moderate heights that were too high for them to be caught in light traps and migrated southwards again, this time using winds that were blowing south, rather then hoping for an autumn thunder storm. Although this looks like a reverse migration it is thought unlikely that they ever get back to the Canaries. Most would have got to the south of France or Spain and survived the winter there.

The Silver Y is not the only moth to undertake long migrations, and some like Plutella Xylostella, the Diamond Back Moth, are true international travelers. The Diamond Back Moth is a pest of brassica (cabbage family) crops all over the world, and sometimes can occur in huge numbers, in one outbreak we were counting up to a thousand moths every day in individual Rothamsted traps. (There would have been hundreds of thousands in mercury vapour traps.) Like the Silver Y the Diamond Back uses a variety of strategies, including thunder storms, to get around. Even a moderate outbreak can devastate a crop of Brussels sprouts, and farmers spray at the first sign of a diamond back caterpillar. In the 1980s I helped grow sprouts for scientists investigating alternative control measures for this pest, but of course the moth never arrived, and for three years running we had more perfect sprouts then we could give away. I'm afraid that I don't have a picture of a diamond back moth. Even if I caught one I could not take a very good picture with my camera, as the diamond back moth, in spite of its superhuman power, is only a millimeter long.

Female Ghost Moth

This is a Ghost moth. Really. It does not look very spooky because it is a female. The males are white, and being quite large can be scary at night, especially when several dozen are carrying out their swaying flight in a lek, hoping to attract females.
Ghost moths belong to the very primitive family of moths called Swift moths, believe it or not because of their rapid flight. The adults have no functional mouth parts, and being unable to feed have to find mates and breed within a fortnight. Don't be too sorry for them, though, as they are quite long lived for moths, the caterpillars feeding for up to three years on plant roots.
The Ghost moth caterpillars feed on the roots of grasses and many other herbaceous plants including nettles, docks, burdock and wild strawberry.

15th July 2013: Rosy Footman

Rosy Footman Moth

This pretty little moth is a Rosy Footman Moth, and is a member of the Footman sub family of moths. They are called "Footman" moths because they always rest with their long narrow wings held over their backs, or wrapped tightly around them and this reminds some people of stiff weather proof coats worn by Victorian outdoor servants.
Rosy Footman Moths normally fly from mid June, so this year they are about a month late, probably due to the cold spring. However they feed on Lichens on oak trees, and this year most of the lichen that I have seen has been dead, or at least inactive, and this may have been due to a combination of last summer's very wet (and continuously wet ) weather, the cold winter, and late spring. Remember that much lichen grows in exposed places high up on the trunks and branches of trees, and must be sensitive to extreme weather. Lichens like damp conditions, but very heavy rain can damage the colonies. The moth over-winters as a caterpillar, which normally feeds in mild weather in winter. The combination of difficult weather conditions and relative lack of winter feeding opportunities, probably means that we are very lucky to see this moth. It is very likely that the weather that is harming this species of moths (and the lichens on which it feeds) is due to climate change, and is just another indication of how serious a problem climate change is. Next time that you are offered the chance to reduce your carbon footprint, please let this pretty little moth add weight to the argument!

17th July 2013: Moth-ers' problems and a Moth's scary solutions

Wainscot moths

Common Wainscot MatthewsWainscot Now my moth identification is rather rusty, but I think that you can see that the two moths above are vaguely related. The first looks to me like a Common Wainscot moth (Mythimna pallens), and it has a random pattern of faint black dots on the wings. The second looks like Mathew's Wainscot (Mythimna favicolor), with a much more regular pattern of dots. (There are of course other ways to distinguish between these species, but I photographed them before checking, and have sent them to Barry for formal identification.) However there is a problem with "random", and that is that there is no reason why a species of moths with a random pattern of dots should not have a pattern like the one that I have suggested is a Mathew's Wainscot. Of course the Mathew's Wainscot could not look like a Common Wainscot, because the Mathew's has a fixed, not a random pattern. So the dots don't really help to distinguish between these two individuals. Now the Common Wainscot really is common, and occurs almost everywhere that grass grows, and is quite common at Glyn-Coch, but the Matthew's is a salt marsh specialist, and there is no salt-marsh at Glyn-Coch. However about 2 miles away by road, and perhaps less if you follow the river system there is salt marsh, so I am fairly confident that Barry will confirm that the second moth is a Mathew's Wainscot.
{EDITORS NOTE: The identifier did not agree that there was a Matthews wainscot moth in this catch. This shows how important the continued involvement of expert identifiers in the survey is! ]

The use of features that are not part of the specimen in order to identify it, is known to ecologists as the "jizz" , and helps experts on insect identification to have more confidence in their work. Jizz includes many factors including local habitat feature, altitutude, latitude, aspect, and even the weather on the day. However learning the jizz is a slow process, and should not replace identification technique. Knowing the jizz of an area gives useful clues as to the species that may be present, and may help improve the confidence of identifications of species that are only glimpsed. This preliminary identification in turn gives clues as to how to trap the glimpsed insect and confirm the identification. As you can see, survey work is full of doubt and the need to check and re-check every identification, using evrything about the insect and the environment that may help confirm the identification! Those who "know a species" instantly are usually wrong. THose who "know" and are always right, are very rare. But if we are to provide accurate information to Governments etc. every identification must be 100% correct.

So much for moths innocently confusing us, but it is a dangerous world out there, especially if you are a nice juicy moth. So some moths use spectacular camouflage as the Garden Tiger (below) demonstrates. Garden Tiger

The Garden Tiger sometimes flies in daylight, and is often reported as an unusual butterfly. Its black and white stripes work rather like a zebras stripes and provide equally affective camouflage in daylight and during the night when it normally flies. But if a predator is not fooled by the stripes the moth has another weapon. By flicking its forewings it can reveal its ultimate deterrent: - Garden Tiger

The sudden appearance of another layer of colour can be quite alarming on its own, and it shows that the predator has been detected. Many insects use red or other bright colours to signify that they are poisonous and this message reinforces the sudden change in appearance. Poisonous insects usually extract the poison from their food plants, though Garden Tigers feed on nothing more dangerous then nettles, docks burdock and other herbaceous plants.

18th July 2013: Other forms of camouflage

It is often difficult for us to work out how a moth's camouflage is meant to give protection, but these pictures of

Swallowtail moths may give a clue. : -


The newly emerged moth is a nice primrose yellow, and you can imagine that as it settles on a plant it may be confused with an elaborate blossom. But those tails on the wings must affect their aerodynamic performance. Are they their to improve flight characteristics or is their some other purpose? If they impair flight, what possible function can compensate for the penalty? Perhaps if we could measure the aerodynamic penalty we could use that value as a measure of the benefit from camouflage.

Swallowtail with wings open

With open wings the spots each side of the "tails" on the hind wings look like eyes, and the moth is offering the predator two whole insects, safely away from the the moth's real head and thorax.

PICTURE Oblique view of Swallowtail with wings partly open

But upright, and with the wings slightly open the Swallowtail moth offers the predator a whole "toad". Should the predator change its mind and attack from the other side it will, of course see another. But are these "fake" animals potential alternative prey, or are they themselves fake predators? Is the moth threatening its predators with a "Gruffalo"? Of course this is a difficult problem to sort out, but is the kind of interesting problem that many entomologists are working on. After all knowing what these shapes represent may tell us about long extinct species that were around when the moths evolved, and understanding what scares an animal which is a nuisance to both us and moths may help us protect crop or even human health.

While a newly emerged Swallowtail is yellow, they go white as they lose scales, and the appearance of the fake animals will also change, and this may change their meaning to predators. Perhaps a young female Swallow tale, full of highly digestible eggs, needs protection from different predators as she finishes laying her eggs, or the more adventurous males are more exposed to birds then the females who may be more vulnerable to rodents. Almost every aspect of insect life raises fascinating problems like these, and many of the answers have the potential to improve our lives as well.

23rd July 2013: Another Footman struggles in.

Common Footman

It is now nearly half way through the flight season of The Common Footman, and this is one of the first we have seen. Like the Rosy footman, it feeds on lichen on trees, and I suspect that like the Rosy Footman, the Common Footman has been delayed by the affect of last years wet summer on lichen, followed by a long and hard winter and late spring.
Having said that, it is a pretty and distinguished looking moth, and has a wonderful tactic for escaping from predators. When disturbed it flips onto its back and rotates very rapidly, sliding down whatever surface it happens to be on, until it falls off and continues to rotate, until it is safely buried in the undergrowth. It sounds pretty boring, but I assure you it is anything but boring when you see it! I should imagine that it usually escapes safely.

26th July 2013: Macros and Micros.

There are thousands of species of lepidoptera even in the British Isles. We are all used to the rather arbitrary division between Butterflies and Moths. Moths, themselves, are divided into the larger moths (macros) and smaller moths (micros). Like the division between butterflies and moths there are species which seem to overlap any division that you describe. However before the advent of relatively cheap binocular microscopes it was quite difficult to accurately identify some of the moth species now described as micros, and as a result the whole families of these tiny moths were defined as "micros" and generally excluded from environmental monitoring schemes such as the Rothamsted Insect Survey. However that is not to say that micros are unimportant, indeed species such as the clothes moth, and the various fruit tree tortrix moths can be important pests. With the advent of cheaper high quality binocular microscopes and examining lenses interest in Micros is increasing, and as long ago as 1986 Barry Goater published an identification guide to micro moths.

There are about 1000 species of macro moth in the British Isles, and they occupy most habitats, and for practical purposes that is enough for environmental monitoring purposes, but even so note is taken of some micros like Plutella Xylostella, the Diamond Back moth (mentioned above) that have particular interest.

PICTURE Macro and Micro Magpie moths

The above moths are both called Magpie Moths, for obvious reasons, but the one on the left, The Small Magpie (Eurrhypara hortulata) is a micro-moth, a member of the Pyralidae family, and feeds on nettles. The larger moth is a macro moth Magpie (Abraxas Grossulariata) is a geometrid moth and feeds on a wide range of shrubby plants including gooseberries, of which its caterpillars are a pest. The Latin name of Gooseberry is ribes uva-crispa, but it used to be known as ribes grossularia, which is where the large magpie moth gets its name - "grossulariata".

27th July 2013: Another micro. Navigation in moths and butterflies. A strategy for winter breeding

China Mark Moth

This little moth is another Micro and is probably a China Mark moth, which is interesting in that its larvae are described as "entirely aquatic". The fact that moth larvae can live at the tops of trees, in the soil and in water is one of the main reasons for their popularity in environmental monitoring. Animals from all sorts of habitats can be attracted into a light trap, and as the variation of the size of catch from year to year indicates the health of the habitat in which the larvae live.

In spite of its small size this China Mark Moth has flown a couple of hundred yards from the most likely source of water from which it will have emerged. Although small insects sometimes use air currents to get around, and become "aerial plankton" recent research seems to suggest that lepidoptera (especially butterflies) fly by the most direct route from place to place. Thinking of the way that butterflies bob along a hedgerow, I used to find the direct flight idea very hard to believe, though I have noticed that when they fly over the sea, they appear much more purposeful. The other day we took our grand daughter to The National Botanic Garden of Wales, and while walking round a lake I observed a Cabbage White fly nearly the full length of the lake in a perfectly straight line.

So why do butterflies and moths appear to fly around so aimlessly? The answer is that they never actually fly for fun. They are always busy doing something of vital importance. When they fly along a hedgerow they may be looking for nectar producing flowers, looking for mates or looking for a food plant on which to lay eggs. Males of some species also patrol their territories and attempt to drive off rivals. Do you remember the huge antennae of the male Drinker moth (above)? The antennae were there to detect tiny quantities of airborne chemicals released by the female moth. Airborne chemicals are very important to lepidoptera for finding their larval food plants as well as mates, and the plants or insects that release the chemicals appear to the moth as a distant point source which releases a plume of chemicals down wind. So lepidoptera fly up wind towards the source. However at any one time they only know that they have detected a molecule of the chemical which they experience as a scent. To find out where the centre of the plume is they have to fly across the plume, and then fly upwind from the centre of the plume. However when flying along a hedge or over undergrowth there are countless little eddies, so the moth or butterfly has to keep turning aside to check its position within the plume. The food plants of many species may be very small relative to the surrounding plants, so these species will continue to fly upwind until the scent abruptly stops, whereupon they will drift downwind until they pick up the scent again and then dive down into the undergrowth, and perhaps do the final search on foot. The same applies for males looking for females, who may remain hidden from predators at all times. Indeed the females of some species of moths do not even grow wings, and tree feeding species may never leave their food plant. (Most of the species, that I can recall, that have wingless females are tree feeding species whose males fly in the winter, when flight may be particularly hazardous, with the added danger of relative exposure after leaf fall, and rain which can knock small insects out of the air.)

30th July 2013: Other difficulties. Leakng colours. Post mortem identification.

Do you remember the little blood vein moth that I showed you on the 27th June?

Well that was a "normal" moth with a thin band of red on the outer edge of the wing forewing. But today we had one with a thicker band: -

Blood vein spread

The extent of the "leak" of red from the outer band on this individual is still not unusual, but a few years ago we caught an individual whose "leak" had covered the whole wing, and it was so unusual that it was recorded in a scientific journal. Variation is normal in living organisms, but is much more common in plants, that have to adapt to environmental conditions in one place, then in insects who can move to places that suit them better. Often when insects have strange colour patterns it is because they have been feeding on the "wrong" plant, or there is something else unusual happening in their environment.

But nevertheless there are natural variations between insects, and sometimes the variation within species exceeds that between species, so in order to preserve species it is sometimes necessary to do the opposite of what you want to do and kill a few individuals in order carry out an examination which is detailed enough to be absolutely certain that you are studying an insect of the right species. Sometimes knowledge gained from dissection will show that only one of two similar species is present in a particular area, so confusion between species may no longer be a problem, at other times dissection helps to identify particular visual features that can be used to distinguish between species in future. There are also particular insect groups where it appears that one species is evolving into two, or two species are converging, and of course a lot of important lessons can be learned from studying these groups.

However, in environmental monitoring the point is that you can correctly identify all species that are present now, and in the future. Of course you cannot tell when or what species may move into or leave an area, so you need to be absolutely certain of each identification. Therefore environmental monitoring surveys like the Rothamsted Insect Survey, use very low power traps which catch relatively few insects, and kill the insects so that the highest possible standard of identification is possible. Along with that goes the necessity to record every single insect identified on a permanent database, and the permanent preservation of catches from reference traps, or traps which are of particular importance. .

3rd August 2013: Ruby Tiger

Ruby Tiger

Normally when a moth has a name like "Tiger" you would expect something pretty spectacular, and this little brown "jobby" doesn't look the part at all! But click and you will see why it had to have an impressive name. However, in fact the "Tiger" refers to the moths relationship to the bigger showier, stripier Garden Tiger, but I think that you will agree that "ruby" is a fair description of that spectacular hind wing.

The bright red of the hind wing and the abdomen, means that when in flight you see a scarlet spark dashing around at high speed, but the moment that the moth settles it folds its forewings around itself and can hide in full site! Of course, if it is detected then the Ruby Tiger can flash open those ruby hind wings and suggest to any predator that it might be highly poisonous as well.

PICTURE (Users of Firefox, Opera, Chrome etc can close the moth's wings by pressing the browser "refresh button", or the function key "F5" on your keyboard. Users of Internet Explorer click here to see the open winged version of the picture, and then the back button to return to this page.)

The Ruby Tiger flies from May to July and sometimes flies by day, so this specimen was rather late. The caterpillars feed on ragwort, plantain, heather, spindle and broom. It lives in most open habitats including down-land, open areas in woodland, set-aside farmland, and gardens.

6th August 2013: Sexual dimorphism in Drinker moths (also see 13th July)

Male and female Drinkers

The male, in the foreground, is the one we usually catch, and the large pale female always comes as a bit of a surprise. But size and colour are not the only differences, as we saw in July, the male has very large antennae.

8th August 2013: Bordered Beauty Moth

Bordered Beauty

The Bordered Beauty is a moth with a very distinctive wing pattern and should be easy to identify, but as moths usually close their wings in the traps one gets used to identifying moths with one wing showing at a time, as in the upper picture. You tend to concentrate on the important features such as the way the brown line tapers into the upper corner of the wing. When you have to identify the occasional specimen with its wings open, your eye is someties attracted to the thick broad band on the inner edge of the wing. Of course, with experience, this becomes less of a problem, though painful memories of hours spent scouring books such as Bernard Skinner's Moths of the British Isles, or Paul Waring and Martin Townsends Field Guide to Moths of Great Britain and Ireland, for what should have been easy identifications, still linger. The Bordered Beauty flies between July and September and the caterpillars feed on Sallows, Alder, Willow, Hazel and Poplar. Its preferred habitat is said to be Carr Woodland, and also in rides and clearings in damp woodland, but also "in scrub or gardens away from woodland".

The preference for "carr woodland" is interesting because some of our lower lying land was waterlogged when the railway was built along our boundary in the mid 19th century, and the old drainage ditches were blocked or diverted. The presence of Devil's-bit Scabious indicates that this is now "ancient wetland". However, in 1998 part of the area was put into a "Farm Woodland Scheme" and the prohibition on any activity that would prevent trees growing there allowed willow to creep in to replace the planted poplar and alder which couldn't cope with the exceptionally wet conditions. The result is something equivalent to Carr Woodland which represents a stage in the natural progression from reedy wetland to fen to Carr Woodland, and eventually to forest.

8th August 2013: Gold Spot Moth

Gold Spot Moth

This spectacular moth is the Gold Spot Moth a member of the Plusiinae group , whose members also include the Burnished Brass, the Golden Plusia, the Silver Y, the Beautiful Golden Y, The Gold Spangle and Stephen's Gem. All these species have very striking metallic looking patches on their wings, the shape and colour of the patch often being so spectacular as give rise to the common (and sometimes even the scientific) name. Like many of the moths on this page their beautiful appearance often causes a sharp intake of breath as one inspects the days catch, even though some, like the Silver Y, for example, can be important pests.

The Gold Spot has two generations in southern Britain, the first in June and July, and the second in August and September, though north of Yorkshire there is only one generation between June and Mid August. It is normal for moths to have two or more generations (or even to be "continuously brooded") at the centre of their geographical range, while towards the extremes of latitude the number of generations each year falls away. Many British species, which are "continuously brooded" in Southern Europe or North Africa only produce a single generation each year here. One of the ways that we can monitor climate change is by monitoring the northern (or southern) edge of a moths geographical range, or the latitude at which the number of generations it produces each year changes.

This year we have also surveyed moths using Pheromone traps, in particular we were interested in Burnet moths which are not attracted to light traps. However the only moths to be attracted to the Burnet pheromone were Gold Spot moths! Gold spot caterpillars eat tufted sedge, glaucous sedge, yellow iris, etc. In captivity they will also eat nettles and willow. Their preferred habitat is damp including ditch banks, rivers, canals, fens and marshes, heathland and moorland, woodland rides, and upland pastures. (Perhaps they also liked our "Carr Woodland". We certainly have plenty of yellow iris and willow for them.)

23rd August 2013: Canary Shouldered Thorn

Canary Shoulderd Thorn

The Thorns are an amazing group of insects, with one species or other flying throughout the spring and summer, and each one appearing to be more beautiful and delicate then its predecessor, and then when you think that you have seen every possible variation of Thorn "style" you catch one of these. Talk about a head of yellow hair! To some the Canary Shouldered Thorn is the pinnacle of lepidopteran beauty, but I find them a bit brassy myself. But you decide for yourself. Canary Shouldered Thorns fly from late July to mid October. and the caterpillars feed on Hazel, Blackthorn, Hawthorn, Birch, Alder, Salows, Honeysuckle, Bog Myrtle and other woody broadleaved plants. Their preferred habitat is woodland, hedgerows, scrub, parks and gardens. They can be found almost anywhere in the British Isles.

23rd August 2013: Flame Carpet

Flame Carpet moth

Dont worry, this little moth is not going to set fire to your floor coverings. The "Flame" refers to the brown ("rosewood-red-brown") band in the wing, and the "Carpet" is the name given to quite a large group of similar moths, probably because the person who originally named the group found one resting on the floor. (I don't know of a single carpet moth that eats carpets, though a very diferent sort of moth , a micro moth Tineola biselliella) "the Common Clothes Moth" does.

Flame Carpets fly in May and June and a second generation flies from July to September up to the Scottish border. North of the border a single generation usually flies in June and July, but in the warm summers of 2003 and 2006 they produced a second generation. This second generation in Scotland will become more common as the climate warms. Flame Carpet caterpillars have not been studied in the wild, but will eat wallflowers and other crucifers in captivity. They are fairly common throughout he UK, but are more abundant in the north and west. They can be found on upland grassland and lowland woods. hedgerows and downland.

23rd August 2013: Flame Shoulder

Flame Shoulder moth

My, we do seem to be having a lot of old flames today, dont we? In this case the "Flame" refers to "the bright straw coloured band along the leading edge of the forewing. This "flame" is further emphasied by the black streak behind it." (Quoted from Waring and Townsend)

Flame shoulder moths are quite common and fly for much of the summer, and with their unusual "flame" mark are one of the first species that novice identifiers learn to recognise. While other moths may be more exciting the tough little flame shoulder moths rarely wear many of their scales away.....though come to think of it, there were one or two...... This species flies (as two generations) from April to September, with peaks in May-June and again in August, and is common almost everywhere except on very high land. In Yorkshire it has only produced two generations a year since 2000, and in Scotland only one in late May-June, but even here a few late specimens have been observed in very warm summers. The caterpillars feed on a wide range of herbaceous plants.

23rd August 2013: Setaceous Hebrew Character Moth

Hebrew Character Moth

But here is a real old flame. I started my stint as a moth identifier bang in the middle of the flight season for the Setaceous Hebrew Character moth. The black saddle shaped mark half way along the leading edge of the forewing is supposed to look a bit like a character in the Hebrew alphabet, and never varies. Even when an old moth has almost no scales left on its wings the outline of the character mark is almost always still visible. I thought that I had cracked this new profession, until clays and square spots turned up and then there were the November Moths. And then, the following spring, the Quakers started arriving and I had to get my mind around the other Hebrew Character (Orthosia Gothica), and later the fact that the flight periods of the two similar Hebrew Character moths overlapped. Of course, distinguishing them is easy when you are dealing with fresh young moths, but old specimens after bad weather can be rather different! Setaceous Hebrew Character moths fly from May to July, with a second generation between August and October, they are common and well distributed all over the Britsh Isles. It is thought that the second generation is too abundant to be entirely the product of the British first generation, and consequently some people suggest that the second generation is boosted by immigrants from across the Channel. (Sorting this out may be a job for our radar trapping colleagues?) The caterpillars feed on a wide range of herbaceous plants including common nettle, white dead nettle, willow herbs and burdock. They are lowland species of woodland and marshes, but most abundant in cultivated areas including gardens. Eco warriors should note that this is a species that benefits from farming and gardening.

For more information on The Rothamsted Insect Survey click here


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