Although moths traditionally suffer from a less than glowing reputation compared to the idyllic summer butterfly, there is still much to recommend them. And they are in need of our help. Ben Aldiss explains
We all love butterflies. As most of them rarely fly unless the sun is shining and the temperature tops 17C, they epitomise balmy summer days.
With their gaudy colours and jaunty flight, they can gladden the heart of even the most jaded of teachers. But what about moths? Horrible, fluttery things that come out at night, apparently with the sole intention of dashing themselves to death on the nearest light bulb. Their diet does little to redeem their reputation either - remember that expensive jumper you had to throw away last winter? At least butterflies are civilised in their eating habits. Or are they?
You might be surprised to learn that moths have much to recommend them, and that butterflies are not as always as innocent as they appear. The Purple Emperor Butterfly, for instance, is very partial to sipping the fluids from fresh excrement, by way of a change from the nectar of blackberry flowers.
There are 50 times more moth species in Britain than butterflies. Of these, 2,500 types - by far the majority - are night-fliers, but a surprising number regularly fly by day and some are as diurnal as butterflies.
Generally, these are poisonous species that advertise their unpalatability with warning colours that positively glow in the sunshine.
More beast than beauty
Tiger moths use this strategy. Adorned with an array of brightly coloured spots and stripes so dazzlingly garish as to make any bird think twice about eating them, they outdo butterflies in their bid to get noticed. I once saw hundreds of Scarlet Tiger Moths in the damp recesses of a gorge in southern Greece. Clouds of these beautiful insects flew up from ooze dripping from mossy boulders - a breath-taking sight. Although this moth is found in Britain, the Garden Tiger Moth is more commonly seen. Larger and even more colourful than its cousin, this moth produces one of the hairiest and fastest-moving of all caterpillars. As it gallops across the path in the shimmering heat, its sleek, chestnut-brown hairs, tipped with silver glinting in the sun, it's easy to see why this comical caterpillar is nicknamed the woolly bear.
Another relative, the Cinnabar Moth, is called after the splashes of vermilion on its otherwise dull black wings. Reminiscent of the mineral with the same name, this colour signals that the poison that is sequestered from the toxic food-plant of its caterpillar. The familiar orange-and-black striped caterpillars can often be seen in large numbers as they completely devour the yellow-flowered ragwort.
Why are colourful moths that fly by day not called butterflies? It's a good question - and one that doesn't have a totally satisfactory answer. There are numerous differences between moths and butterflies, but only one is exclusive: the row of tiny hooks that joins the hind wing to the front one in moths. It doesn't exist in butterflies. The other differences all have exceptions: most moths are night fliers; they have stout, hairy bodies; their antennae are not clubbed at the tips; their caterpillars spin cocoons; they don't fold their wings vertically over their backs.
Survival by variety
Among the more usual night-flying moths there are drab, rather boring ones, but many of the larger species are beautifully patterned and often remarkably colourful. Take the Peppered Moth, for instance. Beloved by geneticists, this species is handsomely speckled with silver and black, camouflaging it superbly against lichen-covered tree-trunk. Since the Clean Air Acts came into force in the 1950s and 1960s, the uncommon black variant has been easily picked out by predators as it tries to remain inconspicuous by day, but at the height of the Industrial Revolution, the reverse was the case. In the Black Country, this mutant rapidly became the prevalent form, as the normal variety stood out starkly on soot-blackened surfaces and was snapped up by hungry birds.
Many moths have cryptically coloured forewings which they close, roof-wise, over the hind pair until nightfall. If a bird happens to disturb such a moth, it will suddenly open the forewings to flash the brightly coloured back ones. This is usually sufficiently shocking to frighten the bird away.
The Yellow Underwing employs this technique, but the Eyed Hawk Moth goes one step further. With pink hind wings, each emblazoned with a large and very realistic-looking eye, it appears much bigger than it really is and must seem like a fearsome predator to the average-size bird.
The Eyed Hawk belongs to a family of impressive moths, many of which are very large and all of which fly extremely fast - like the predatory birds from which they get their name. Not only are these species spectacular as adults, but most of them have enormous caterpillars. The thrill of finding one is made all the more exciting, as most of our 18 species are rather rare. Related to the Eyed Hawk are the Poplar, Pine, Privet, Convolvulus and Lime Hawk moths - all conveniently named after the main food-plant of the caterpillar. Of these, the Convolvulus Hawk is the rarest, being a migrant that frequently reaches our shores from as far away as Italy and North Africa.
Though less scarce, the Privet Hawk is sufficiently uncommon to cause a major stir when one appears in the UK. Our largest native moth, the Privet Hawk is a beautiful creature with pink hind wings and a pink and grey ringed body. The caterpillar is even more spectacular, growing to a full eight centimetres long. Bright green, with seven oblique purple and white stripes along its sides, it has an impressive shiny black and yellow horn at its tail end. This totally harmless feature is a trademark of the family - nearly all hawk moth caterpillars have them. The Latin name of the Privet Hawk is Sphinx ligustri, referring to the shape of the caterpillar, which supposedly looks like the sphinx of Ghiza in Egypt when at rest. Its other name - Ligustri - is Latin for privet.
Britain's biggest moth is in this family too. The Death's Head Hawk Moth is enormous and - as everyone who has seen Silence of the Lambs will know - the markings on its broad black and yellow body look remarkably like a skull. At nearly 13cm long, its caterpillar is huge. It feeds on potato leaves, but is very uncommon in Britain, the moth appearing here only as a rare migrant.
Much superstition surrounds this moth, and not just because of the skull-like markings. The adult is very keen on honey and habitually raids beehives to get it. Normally, if the guard honeybees at the hive entrance don't repel a potential plunderer, the many thousands of worker bees inside will sting it to death; for many years it remained a mystery as to how this large moth could gain access with impunity. But we now know that the moth makes a high-pitched squeak which has an instant placatory effect on any bee nearby. This squeak (known as "piping" by beekeepers) is an exact mimic of the noise made by queen honeybees as they search out and kill their rivals. Sound emission is not restricted to the Death's Head Hawk Moth: recent research has shown that ultrasound frequencies are emitted by some smaller moths, not to placate bees, but to "jam" the sonar devices of bats.
The Emperor's enigmatic clothes
Hawk moths may be the flagship species of Britain's moth fauna, but there are many other fascinating and unusual kinds worthy of mention, among them the Emperor Moth. It is the only member of the silk moth family found in Britain, for example. From its beautiful smoky-grey eggs to its colourful caterpillars and golden cocoon, spun from a single strand of silk hundreds of metres long, its life history is full of interest, but it is the male moth with his feathered antennae who provides the biggest surprise. His antennae are so sensitive he can detect the presence of a single female five kilometres away.
Perhaps the most enigmatic species of all is the Puss Moth, so called because of its resemblance to a white fluffy cat. This moth has one of the strangest-looking of all caterpillars. Laid singly, or in twos or threes, on willow leaves, the hemispherical eggs are an unusual brick-red colour.
From them hatch tiny jet-black caterpillars, each with a long forked tail and a head with two "ears" sticking out at the top.
As each caterpillar grows, it becomes fat and green with a purplish-grey saddle-like marking on its back. When threatened, for example by a parasitic moth, it draws its head into the first segment of its body, until it looks like an enormous nose on the face of a clown - beneath this is a slit-like "mouth", while above it are two pinkish marks that look like eyes. At the same time, it extrudes long red and white "whips" from its two tails, thrashing them about over its back - altogether a very frightening experience for any potential predator.
When ready to pupate, this large caterpillar becomes restless, turns purple and spins a cocoon of silk around itself on the bark of the tree. Finally, it chews off pieces of bark, mixes them with gluey saliva, then pushes them through the network of silk to stick them to the outside of the cocoon.
Within an hour or so the cocoon hardens and looks exactly like a bulge in the bark of the tree. The following spring, the emerging moth secretes an enzyme to digest the silk before pushing its way out of the softened cocoon.
British species in danger
Recently the subject of a BBC Radio 4 Nature broadcast (see resources), the drastic reduction in the numbers of most British moth species since the late 1960s has been highlighted in The State of Britain's Larger Moths, produced by Butterfly Conservation, Britain's leading protector of lepidoptera and their habitats.
This report is based on data from light-traps which have been in use across the country for the past 35 years. With a fall in numbers of nearly one-third over this time, Britain's moths are in desperate need of Butterfly Conservation's inspirational help.
* Butterfly Conservation
Organisation dedicated to the conservation of British butterflies and moths and their habitats. President, Sir David Attenborough; vice president, Alan Titchmarsh. www.butterfly-conservation.org
* BBC Radio 4
Moths, broadcast February 20, 2006 www.bbc.co.ukradio4sciencenature_20060220.shtml
* The State of Britain's Larger Moths
By R Fox, KF Conrad, MS Parsons, MS Warren, and IP Woiwod Butterfly Conservation and Rothamsted Research, Wareham, Dorset. This full-colour booklet can be bought online from the Butterfly Conservation website (above), Pounds 5.00 plus pound;1.50 pp.
Website for all butterfly, moth and dragonfly enthusiasts.
* Rothamsted Research
Internationally renowned scientific research establishment and the oldest agricultural research station in the world. Provided much of the data for The State of Britain's Larger Moths.
LIFE-CYCLE OF A PUSS MOTH
Puss Moth life-cycle:
1 eggs are laid singly, or in twos or threes
2 It's odd-looking caterpillar has long, defensive red and white "whips"
3 When ready to pupate the large caterpillar spins a cocoon of silk around itself
4 Pupa (sometimes called a chrysalis) rests while its body tissues completely reorganise to become..
5 ...the adult Puss Moth
It's not just butterflies that can be beautiful... right: a spectacular male Emperor moth (inset shows larva and shed skin).
Opposite (top)Banded Woolybear Caterpillar; the olive-brown and pink Elephant Hawk moth; below (left) the Privet Hawk moth and (right)the Scarlet Tiger Moth, with its dazzling array of brightly coloured spots and stripes
Most moths are easy to rear and they can add an extra dimension to science lessons. Here are some hints on how to go about it: Find your specimens
Many native species are becoming rare, so collecting caterpillars from the countryside is to be discouraged. But even the average-sized garden will provide a few, especially from those neglected corners and uncut hedges.
The most productive plants are shrubs and trees, especially willow, oak, apple and hawthorn. Lower-growing species are also worth searching - dock, dandelion, thistles and nettles all provide food for a number of moth caterpillars.
Suppliers of live specimens are a more expensive option, though well worth considering, as the livestock they send is guaranteed to have been bred in captivity and the choice includes some truly spectacular exotic species, such as the Giant Atlas (the world's largest moth) and the Indian Moon Moth, both of which produce enormous and colourful caterpillars.
Worldwide Butterflies is a well-established and reliable supplier of livestock for schools ( www.wwb.co.uk).
What does it feed on?
If you collect a caterpillar from your garden, make sure you take a piece of its food-plant too. Some species feed on a variety of plants; for example, the Garden Tiger Moth will eat most weeds. Others are more particular, like the Cinnabar Moth, which feeds mainly on ragwort. Be careful not to take too much of the plant at one time, especially if it is a prize garden specimen.If you're not sure of its food-plant, find the name of the caterpillar, then look up its details. Useful publications and websites to help you include:
* Foodplant List for the Caterpillars of Britain's Butterflies and Larger Moths by Tim Crafer. Atropos Publishing, pound;21.95.
* The Colour Identification Guide to the Caterpillars of the British Isles by Jim Porter, Viking Press, pound;40.
Website showing photos of more than 1,600 species of British moths to help with identification.
Website showing colour pictures and names of the caterpillars of 800 British moths.
If you send off for caterpillars, instructions will be provided and the caterpillars will arrive with some of the food-plant (NB ensure that enough of a suitable plant exists in the school grounds before you order.) Housing your caterpillar
Small caterpillars can be kept in clean dry jam-jars with the lids screwed on, but never stand such containers in a sunny place, or they will over-heat.
Place a piece of tissue-paper in the bottom to absorb condensation, then put the caterpillar inside with a freshly cut twig of its food-plant.
Contrary to popular belief, it is not necessary to punch holes in the lid, as caterpillars have a very low rate of metabolism and use up very little oxygen. In fact, the food-plant will rapidly wilt and dry out if the container has air-holes.
Clean out the jar daily and replace the food. To avoid waste, put in only enough food to cater for the caterpillar's needs.
Large species or multiples of smaller ones need bigger accommodation.
Biological or scientific suppliers such as Watkins and Doncaster (www.watdon.com) or Griffin Education (www.griffineducation.co.uk) provide various multi-purpose designs, as does Worldwide Butterflies.
To avoid damaging your caterpillar when replacing its food, coax it off its old twig using a fine artist's paintbrush, or carefully cut through the twig on either side of the caterpillar using scissors, then transfer it to the cleaned-out jar.
Rearing your caterpillar
Care for your caterpillar as detailed in above. As it grows, it will need to shed its skin (a process called ecdysis). Signs that this is happening include:
* The caterpillar stops feeding
* It spins a pad of silk on the twig and stands on it, motionless, for up to three days
* Its head becomes hollow and a clear impression of a new, larger head appears under the skin behind the old one
* Eventually the skin behind the old head splits and the caterpillar crawls out
* For about an hour afterwards the caterpillar stands still while its new skin hardens. Many species at this stage eat their old skin - waste not, want not!
While the caterpillar is ecdysing avoid disturbing it - it will not need cleaning out or feeding.
When fully grown (usually after four skin-changes), the caterpillar will need to pupate (change into a pupa or chrysalis). Depending on the species, it will spin a cocoon of silk among the twigs and leaves of its food-plant, or it may need to bury itself in leaf-litter or even in the soil.
After a fortnight, the pupa inside the cocoon can safely be removed, placed on a bed of dry cotton-wool or moss in a suitable container and left in a cool, dry place over winter.
A few weeks before it is due to emerge (check details in websitespublications cited above), the pupa should be sprayed with water once a week and provided with twigs or wire-netting, so that the emerging moth can climb up and dry its wings.
The suppliers cited above provide suitable emergence cages.