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Insect Wings A Photographic Study by The Nature Collection for British Wildlife

Introduction

This is a photographic introduction to the wings of different insect groups. It is a simple look at the wings, with the emphasis more on the visual than the scientific.

I am fascinated by several areas of natural history including bird skeletons, dragonflies and owl pellets. I am particularly taken by the wings of birds and insects. Wings enable the animals to fly and have evolved in such a variety of colours, textures, patterns and shapes. They can be as delicate as a damselfly wing or as immense as the wing of an Eagle owl. The wings may be transparent or mottled brown for camouflage or brilliant, iridescent blue to attract a mate or startle a predator.

Content

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Insect Wings: Introduction

Insects usually have two pairs of wings. In almost every species, the wings enable the insect to fly. Wings are important to evade a predator, find a mate, display, find food and shelter and for dispersal to a new territory. Insects may fly fast like flies, hover like dragonflies, float like butterflies or have short bursts of clumsy flight, like Stag beetles.

For insects, the front wings are called 'forewings' and the back wings are the 'hind wings'. They are described as pairs of wings as the wings are symmetrical; they always have the same shape and pattern on both sides, so the left wing is a mirror image of the right wing.

Insects have three parts to the body; head, thorax and abdomen. Both pairs of wings attach to the middle segment of the insect's body, which is called the 'thorax'. The legs attach to the thorax, too. This is where the flight and leg muscles are.

Wings are in fact part of the exoskeleton, formed by folds of the skeleton, growing out from the thorax, when the insect develops.

Wings can be long or short, membranous or leathery, coloured or transparent. They may fold up under a wing case for beetles, along the body for grasshoppers or be held above the body, for damselflies.

Wings consist of two very thin layers of transparent membrane, stretched over a network of tubular veins, which are like scaffolding, giving the wings their form and structure. The pattern of veins is different for different species of insect and is one of the main criteria used by scientists to classify them.

In this simple, photographic study, I will look at different groups of insects, focusing only on their wings. I have not covered all the insect groups, as I do not have photos of many of the rarer or smaller ones. I appreciate that the variations in wing form are not the only defining feature of the insect groups; there are many more criteria which determine which species belong in each group, such as their mouth parts, antennae, jointed legs, diet or behaviour.

Insect Groups: Names from Ancient Greek

In this study, I will also give the names for the different insect groups, showing their derivation from the Ancient Greek, because the names are based on the type of wing which the insects have. Also, I studied Ancient Greek and Latin at Oxford University and very rarely get the chance to combine my love of Classics with my fascination for insects!

Scientist who study insects are called' entomologists'. This is from the Ancient Greek words, 'entomon' for insect and 'logia' for study. As it is such a vast area to study, with so many thousands of different species, within entomology, there are specialists who study the groups such as butterflies, flies or dragonflies. They are named after their preferred group of insects; so as the name for 'butterflies and moths' is 'lepidoptera', a naturalist who studies them is called a 'lepidopterist'.

Mayflies

This group of insects is called the 'Ephemeroptera'. This comes from the Ancient Greek words: 'ephemera' meaning 'for a day' or 'short lived' and 'ptera' meaning wings.

Mayflies emerge from the water, where they have lived for about year and live just for a few hours or days, as flying adults. As adults, they just find a mate, lay eggs and die. They cannot feed.

Mayflies have one or two pairs of delicate wings. The wings have numerous black veins and cross veins and some dark spots on the forewings.

The forewings are large and triangular shaped. The hind wings are much smaller and shaped like fans.

When mayflies are at rest, as in the photo, the wings are held closed together, vertically above the body.

Mayflies are weak fliers and are usually found in great numbers, close to water.

Mayfly nymphs are important to the diet of many fish. They are often used by fly fishermen, who create model flies, based on them, as bait.

The Mayfly lifecycle is unique among insects. They are the only ones which have a stage as a winged nymph before the final, adult stage. Other insects either emerge as a winged insect from a pupa (e.g. butterfly or bee) after metamorphosis or they hatch from the egg as a mini version of the adult, called a nymph, and keep growing and shedding their skin, getting larger each time, but only grow wings when they reach the adult stage.

Shed skins of grasshopper nymphs at the Natural History Museum, Oxford, showing the lifecycle stages.

There are 51 species of Mayfly in Britain!

Mayfly. Long 'tails' and antennae!

Damselflies & Dragonflies

Dragonflies and damselflies belong to the group of insects called 'Odonata', from the Ancient Greek 'odon' for tooth. This refers to the toothed jaws of the underwater nymphs, who are fierce predators. The group subdivides into two groups, for the damselflies and dragonflies.

Dragonflies belong to the group of insects called 'Anisoptera'. This is from the Ancient Greek words 'an-isos', meaning un-equal and 'ptera' meaning wings, so 'unequal-winged' insects.

Damselflies are in the group called 'Zygoptera' from 'zygos' meaning 'yoked' and 'ptera' for wings, so ''yoke-winged' insects. The base of all four wings are narrow and shaped like a yoke, where they join the thorax.

In damselflies and dragonflies, the forewings are not attached to the hind wings, so all four wings can and do move independently, in flight.

Dragonflies and damselflies have two pairs of wide, transparent wings, which usually have no colour or pattern. Transparent wings are good for camouflage as a predator just sees the plants or water through the wings; often the slender body is in line with a plant stem, too so dragonflies are hard to spot on vegetation.

Well camouflaged!

Most species of dragonfly and damselfly have a black or cream spot at the tip of the wings. This is called the 'pterostigma'. This word comes from the Ancient Greek words 'pteron' for wing and 'stigma' meaning mark or stain.

The wings are covered in a network of numerous thin, black veins and cross veins.

This group of insects live as nymphs, underwater, where they have no need of wings.

There are 47 different species of dragonfly or damselfly, which breed in the UK.

Main photo shows an Emperor dragonfly, female

Damselflies

Damselflies have long, slender bodies. At rest, the delicate wings are folded together and held up, above the abdomen. Their wings are shorter than the abdomen.

Damselflies have large eyes on the sides of the head. Unlike dragonflies, their eyes do not touch in the middle.

Damselflies have two pairs of delicate narrow wings, which are usually transparent. They are covered in an intricate network of thin, black veins and cross veins. The wings are very narrow, where they join the body.

Damselflies have a weak, fluttery flight and are not often found far from water. They can fly up to 10km per hour. Unlike the larger dragonflies, damselflies cannot hover.

Banded demoiselles. The males have a dark blue patch mid way along all four wings
Male and female Banded demoiselles at rest, the wings held closed together, above the abdomen.
Female, Banded demoiselle specimen at the Angela Marmont Centre. See how thin the wings are where they join the thorax.

Note the spikes on the damselfly's legs, which combine to form a basket-like trap when they catch an insect in flight, using their legs.

Large red damselfly. See the black spots at the wing tip.

The wings are long but not as long as the abdomen. They are held closed together, above the abdomen.

Blue tailed damselfly. Huge, heavy eyes! Pale blue and black pterostigma, at the wing tip.
Small red damselflies mating. Red, spiky legs, red abdomen, red eyes and red spots on the wing tips!

Dragonflies

Dragonflies are larger and more robust than damselflies. They have broader bodies and deeper wings. The base of the hind wings is wider than that of the forewings.

The wings beat independently and can twist in flight, which enables dragonflies to change direction so rapidly.

Migrant hawker, in flight

Dragonflies are among the fastest flying insects. They can fly at speeds of up to 36km per hour. They can fly forwards, backwards, sideways, up and down. They can glide and hover in a fixed position. They are often seen patrolling a stretch of water, their territory, looking for a female, seeing off a rival or searching for food.

The vein at the front of the forewings is the thickest. This creates a strong leading edge which helps the dragonfly cut through the air, in flight. If the front of the wing was weak, it would bend and break more easily.

When a dragonfly rests, the wings stay stretched out, to the sides.

Keeled skimmer with pale brown pterostigma, at the wing tips
Four-spotted chaser. Unusually this species has two dark spots on each wing.

Unlike damselflies, dragonflies have huge compound eyes which join in the middle of the head.

Migrant hawker dragonfly specimen at the AMC

In the above photo, note the extra-thick vein at the front or leading edge of the wings; also, the dark 'pterostigma', the mark at the wing tip.

Migrant hawker dragonfly. Look at the cells on the wings. There are squares, rectangles, hexagons and pentagons.
Broad bodied chaser. See the wide wings and black pterostigma at the wing tips. This species also has patches of colour where the wings join the thorax.
1. Dragonfly emerging as an adult 2. Black darter with shimmering wings 3. Powdery blue Keeled skimmer, wings held forward 4. Newly emerged Black darter

Pictures 1 and 4. When a dragonfly emerges as an adult, the wings are soft and need haemolymph to be pumped into the veins. The wings need to dry out and stiffen, before the dragonfly can fly.

The wings can be iridescent, catching the sunlight, as is shown by Picture 2.

A box of dragonfly specimens. See they all have the small patch on the wing tips, called the 'pterostigma'. There are three damselflies in the lower, right hand corner.
Different sort of winged predator! A Hobby, a summer migrant to the UK from Africa, has caught a dragonfly in its talons!

Grasshoppers & Crickets

This insect group is called the 'Orthoptera', from Ancient Greek words, 'orthos' meaning straight and 'ptera' for wings, so 'straight-winged' insects.

The forewings are narrow and leathery, often green or dark brown and patterned for camouflage. They are called the 'tegmen' for this group. The hind wings are membranous and fan-shaped. They fold up under the forewings. You hardly ever see grasshopper wings in the field.

Some grasshopper and crickets have no wings or very short wings which mean they cannot fly.

Grasshoppers on a post.

This group of insects have very long legs for jumping.

The difference between crickets and grasshoppers is that crickets have very long antennae and grasshoppers have short.

There are 35 different species of Orthoptera in the UK.

Main photo shows a specimen box for the Wart-biter, a rare bush cricket, in the Angela Marmont Centre for UK Biodiversity in the Natural History Museum.

Great green bush cricket specimen at the AMC.

Great green bush cricket photo. Note how it is displayed with one wing out and one folded against the side of the body, so scientists can study it in two states.

The wings, longer than the abdomen, are usually held flat against the body. The forewings are tinged green to camouflage with the grass and undergrowth, where the cricket spends its life.

Roesel's Bush- cricket. This species usually has short wings but there can be long-winged forms in hot summers, as here.

This species has clear, delicate wings. The wings are longer than the abdomen.

Roesel's bush cricket with much shorter wings, shorter than the abdomen!
Cricket emerging from its skin!

In the UK, we have the unusual Mole cricket, which has huge front claws for digging like the Mole mammal!

Non UK Mole cricket specimen: thick forewings and iridescent, fan-like hind wings with rectangular cells. Picture 4: Mole cricket display case in the Natural History Museum, Sofia
Grasshopper specimen at the AMC

See the short, leathery forewings, shorter than the abdomen.

Meadow grasshopper.

The Meadow grasshopper, shown above, is flightless. It has no hind wings and very fine, short wings , half the length of the abdomen.

Exotic grasshopper specimens. Note the fan-like hind wings and thicker forewings.
Wings of exotic grasshoppers and crickets!

True Bugs

This group of insects are called the 'Hemiptera'. This from the Ancient Greek words, 'hemi' meaning half and 'ptera' for wings, so 'half-winged' insects. This is because, for a large number of insects in the group, the forewings are leathery at the top half, where they join the body but membranous in the lower half, towards the wing tip.

All insects in this group have a sucking or piercing mouthpart in the form of a tube. It often folds away under the body.

Underneath a non UK cicada, showing the tube-like mouthpart

The group 'Hemiptera' is divided into two sub groups.

One group are called the 'Heteroptera', from the Ancient Greek words, 'heteros' meaning different and 'ptera' for wings, so 'different-winged' insects. This is because the forewings are in two sections, tough and leathery at the top half and membranous in the lower half.

The other group are the 'Homoptera', from Greek for 'homos' meaning the same and 'ptera' for wings, so 'same-winged' insects. This is because the forewings are always the same texture all over, either leathery or membranous, not half and half.

There are about 1,700 species of Hemiptera in Britain.

Photo shows a display case of True Bugs at the Natural History Museum, Oxford

Hemiptera

For these insects, the forewings are leathery at the top half, where they join the body but membranous in the lower half, at the wing tip. The hind wings are membranous and are kept folded away underneath the forewings, at rest.

Shield bug

The forewings lie flat and fold over each other, forming an X shape, across the bug's back, when at rest.

In the UK, the group of Hemiptera includes shield bugs such as the Hawthorn shield bug, Tortoise bug, Parent bug, Sloe bug, and Assassin bug. Also water bugs like the Pond Skater and Water boatman.

Assassin bug, Sloe bug and Pond skater
Non UK specimen. See the forewings are half leathery and half membranous.

Homoptera

For this group of insects, the forewings are always the same texture all over, either leathery or membranous, not half and half.

For this group, the wings are held up like a tent, over the body, when the bug is at rest.

In the UK, the group of Homoptera includes one species of cicada, and several species of leafhopper, treehopper and aphid.

Aphids

Aphids include the garden pests, greenfly and black fly. Aphids are mostly wingless creatures but in late summer, some forms hatch which develop wings. These insects fly off to different plants and start new colonies. This is how these normally wingless insects, extend their territory and increase their chances of survival.

Cicada specimens, non UK. Beautiful wings!
Folding, papery wIng of a cicada, non UK
Beautiful, patterned, blue wings of an exotic Lantern bug

Scorpion Flies

Scorpion flies are in the group of 'Mecoptera', from the Ancient Greek words 'mecos' meaning long and 'ptera' for wings, so 'long-winged'. The wings are exceptionally long, longer than the abdomen.

The narrow wings are covered in a network of black veins. Both pairs of wings have a distinctive pattern of black patches, like stained glass windows.

Scorpion flies have long, slender antennae with many segments. They have an elongated head with biting parts, which points downwards. The males have an unusual tail which curls up like a scorpion's tail.

Despite their long wings, these insects rarely fly.

There are 3 species of Scorpion fly, in the UK.

Beetles

Beetles are in the group of 'Coleoptera'. This comes from the Ancient Greek word 'koleos' for sheath and 'ptera' for wings, meaning 'sheathed wings'. It refers to the fact that a beetle's hind wings are kept in a protective cover, like the sheath for a dagger or knife.

Over time, beetles' forewings have evolved into tough, leathery covers, called 'elytra' which form a protective case over the hind wings; The more delicate hind wings, which the beetle uses to fly, are kept folded up over the back of the body. You rarely see them. You may have seen a ladybird take off or watched a slow-flying Stag beetle take off, on a summer's evening. Look closely next time, to see the hind wings.

The wing cases are different colours and patterns, for camouflage or display. The wing cases meet in a straight line, down the middle of the back. The mid-line starts just below the 'scutellum', a small triangle at the top, where the wing cases meet. For some beetles, the 'elytra' or wing covers do not cover the whole abdomen.

Beetles have adapted, so that they can fly if they need to, but more importantly, their abdomen is protected by the tough wing cases, which form part of the exoskeleton, like a suit of armour.

Beetles' hind wings are thicker and tougher than the wings of other insects. Many beetles are probably heavier, so need stronger wings!

The wings are formed in the same way as for all insect groups, with two layers of membrane stretched over a network of veins, but for beetles, the veins are few. As with other insect groups, the veins at the front of the wings, are the thickest.

Insects in the Beetle group have two other defining characteristics: the last section of the leg is always made up of three or five segments and they have biting or chewing jaws, called mandibles, underneath the head.

There are more than 4,000 different species of beetle in the UK.

Main photo shows an exotic beetle, with outspread wing cases and purple hind wings.

Stag beetle, male
Some of my exotic beetles in The Nature Collection, illustrating the beautiful colours and textures of the wing cases. Beetles are a collector's dream!
Exotic beetle, with brown, leathery hind wings and metallic green wing cases, evolved from the forewings, outstretched as if in flight
Exotic beetles, showing a variety of patterns on the wing cases!

Butterflies & Moths

Butterflies and moths are in the group of insects called 'Lepidoptera'. This is from the Ancient Greek words 'lepis' meaning scale (as in fish or snake scales) and 'ptera' for wings, so insects with 'scaly wings'. This refers to the rows of overlapping, microscopic scales which create the colours and patterns on the wings.

Butterflies and moths have two pairs of large, brightly coloured wings. The forewings are triangular and the hind wings are fan-shaped.

The wings are made of chitin and are actually see-through. They are covered in thousands of microscopic hairs and overlapping scales which create the colour and patterns on the wing. The scales are often three layers deep, maybe a base layer, colour scales and then iridescent scales on top, to catch the sunlight. There may be 600 scales in one millimetre square of wing!

This exotic butterfly has almost no scales on the wings!

As well as giving colour for display, the scales also make the wings stronger and keep the butterflies and moths, warm.

The scales at the edge of the wings are often longer and toothed.

The wings are very delicate. They have a network of veins running across them. The veins contain insect blood, called 'hemolymph'. This is not red but usually colourless.

This group of insects have a slow, fluttering flight, very slow compared to a dragonfly or wasp!

As well as wings covered in scales, insects in this group have a 'proboscis', which is a long tube-like tongue, often coiled up under the head.

Coiled butterfly's tongue

There are over 2,400 species of butterfly and moth in the UK!

Photo shows the scales and hairs on a Moon moth's wing, not a UK species.

Moths

Moths have much more hairy wings and bodies than butterflies. They need to be able to warm up their body, especially the flight muscles, at night, where there is no chance of catching the heat of the sun. Butterflies and other insects need to warm up in the sun each day, before they can fly.

Elephant hawkmoth. So many hairs!!

There is also a theory that a moth's thick hairs help block the clicks sent out by bats echolocating, in their nocturnal hunt for flying insects.

Thickly packed scales, which are so fine they are like hairs, on a moth's wing.

When moths rest they usually keep their wings closed.

One of the main differences between butterflies and moths is in the antennae: moths have a threadlike or feathered antenna whereas butterflies have a slender antenna ending in a club shape.

The first three are moth antennae and the last is from the Peacock butterfly, covered in iridescent scales!
Coloured, iridescent and transparent scales on the forewing and leg of a UK moth
Breathtaking array of colours on a moth's forewing
Golden scales
Buff tip moth. The scales on the forewing here are a very different shape, to other moth species.
Red-green carpet moth. Note the transparent wing underneath the scales.
Red-green carpet moth. Beautiful, patterned, compound eyes, scales on the head and long tongue coiled around the leg
Incredible variety of scales and hairs on the body and wings of a micro moth, less than 1cm total length. Photo taken at the Angela Marmont Centre using the photo stacking equipment
Another micro moth specimen at the Angela Marmont Centre

A small group of moths have feathers instead of scaly wings. These are the Plume moths. Look them up on the internet!

Multi-coloured scales, with a forked edge, tightly packed on a moth's wing

For some groups of moth, the wings are connected by a thin spine on the hindwing, called the 'frenulum', being held in place by a catch or tuft, called the 'retinaculum', on the forewing.

The mechanism for joining the forewing and hindwing in some groups of moth.
Many moths have scales which are iridescent, when they catch the light
The stunning Madagascan Sunset moth!
The metallic scales which give the moth its incredible colours, are shaped like curls!

Butterflies

When butterflies rest, they usually rest with their wings open. This is how we see them on flowers or grasses.

The forewings and hind wings are not physically joined together but move as one because the forewings overlap the hind wings.

Peacock butterfly specimen
Peacock butterfly wing scales. Can you see where these patches fit, on the wings?

The patterns on Peacock butterfly wings look like large eyes. This is to frighten off a predator if they get too close; when the butterfly opens its wings, the predator thinks it has disturbed a much bigger animal with huge eyes!

The patterns on the underside of the wings are darker and provide much better camouflage, perhaps for when the butterfly is hibernating in a dark corner of the shed!.

See the dark patterns underneath the wings. Good camouflage
Small copper butterfly in the field, in the museum and under the microscope!
Iridescent scales near the edge of the forewing of the Red admiral butterfly
Red admiral, front edge of the forewing
Red admiral on the Dorset coast. Large numbers migrate here in the summer, across the Channel.
Red admiral specimens at the AMC, showing the butterfly from above and below and the chrysalis

There are masses of hairs on butterfly wings, as well as the overlapping scales. See the golden hairs on the wing of a blue butterfly from the UK!

Hairs and scales of a Common blue butterfly
Common blue butterfly. Different patterns on the topside and underside of the wings. stripy antennae, hairy eyes and beautiful scales.

Many of the scales on butterfly wings are iridescent. The colours are formed by the structure of the scale rather than a pigment within them. When the wings move, the iridescent scales catch the light and change colour!

Iridescent butterfly scales
Butterfly wing scales under the microscope. Different textures and colours!
Scales overlap like roof tiles.
Coloured scales lying over iridescent ones, on a tiny section of a wing.
Different shape scales reflect the light to create flashes of colour, as they fly
Each scale attaches to the wing membrane, with a tiny hook. How can this all happen during metamorphosis?
Iridescent scales around the veins on a butterfly wing
Different textures and colours of wing scales beside a transparent vein
Butterfly wing. Coloured and iridescent scales and hairs under a microscope

Bees, Wasps and Ants

This group of insects are called the 'Hymenoptera'. This is from the Ancient Greek words 'hymen' meaning membrane and 'ptera' meaning wings, so 'membranous-winged' insects.

Insects in this group, apart from the ants, usually have two pairs of delicate, colourless wings.

The forewings are much larger and wider than the hind wings. Both wings are rounded and narrower at the base.

The wings connect to each other with a row of tiny hooks on the front edge of the hind wing. These hooks are called 'hammuli'.

There are a small number of wavy, pale brown veins on the wings, creating large cells. The thickest veins are at the leading edge of the wings, where they have to cut through the air, in flight.

The wings are tinged brown and are transparent with no patterns. They are covered in tiny hairs, which look like specs in the photos.

At rest, the wings fold back over the insect's body.

This group of insects all have a narrow, pinched waist between the thorax and abdomen. This is called the 'petiole'. These insects all have biting or chewing 'mandibles' or jaws. Bees are covered in branched hairs all over the legs and body, whereas wasps are usually hairless. Ants have elbowed antennae.

There are over 600 different species of bees, wasps and ants in the UK.

Photo shows a Hornet specimen at the Angela Marmont Centre at the Natural History Museum, London.

Bumble bees have such small wings to carry such a heavy body!

Bumble bee specimen at the Angela Marmont Centre, showing the long tongue.
Common wasp specimen at the AMC
Ants are usually wingless.

In late summer, the queen ant lays special eggs which hatch into male and female ants, which grow two pairs of wings. On a special 'wedding flight', these ants take to the air and choose a mate.

The females which have mated, lay eggs, drop their wings and start a new colony. The males die.

Special ants hatch in late summer. They grow wings and fly for just a few days.
Honey bee specimen at the AMC
Bee hive at the Natural History Museum, Oxford. The wings are folded back over the body, to save room in the hive.

There are over 600 different species of bees, wasps and ants in the UK. They have all evolved to live very different lives: some are cuckoos like the cuckoo bird and some are fierce predators. We even have our own leaf cutter bees, like the leaf cutter ants in the rainforest! These could all be flying through your park or garden!

Bumble and honey bees. Note the pink pollen sacs!
Leaf cutter bee and exhibit at the Natural History Museum, Oxford. These bees cut off circles of leaves and use them to build nests, where they lay their eggs.
Cuckoo wasp and cuckoo bee. These lay their eggs in the nest tunnels, dug out by other insects
Bee wolf, a solitary wasp, which catches and paralyses honey bees and carries them back to their nest, to feed their young.
A huge, exotic wasp with thick, blue wings!

Flies

Flies are in the insect group called 'Diptera'. This comes from the Ancient Greek words 'duo' for two and 'ptera' for wings, so 'two-winged' insects. This refers to the fact that flies have only one pair of wings, which is very unusual for insects.

The hind wings have evolved to become just small stalks on either side of the body. They are called 'halteres'. The 'halteres' help a fly to balance and steer when it is flying.

Flies have transparent wings, with dark brown veins running across the surface. The veins, pumped full of insect blood, give the wings a rigid structure.

Compared with dragonflies, flies have fewer veins on their wings, creating larger cells. As with all insects, the experts identify different species by examining the shape and layout of these wing cells, amongst other things.

Flies have sucking or piercing mouthparts which are like a needle or sucking tube under the head.

There are over 7,000 species of fly in Britain.

Main photo shows a Bluebottle specimen at the AMC

Hoverfly specimen, at the Angela Marmont Centre

You can see the 'halteres' on this photo of a hoverfly, inside the blue circles.

Notice how the vein at the front edge, as for the other insects, is strengthened on all these insects.

Variety of UK flies

In some groups of flies, the hindmost section of the wing has been modified into thickened flaps, called 'calypters'. These cover the halteres. This is what you can see in the next photo of the Flesh fly specimen.

Flesh fly at the AMC. Just one pair of transparent wings. See how long and thin these wings are, compared to the Bluebottle.

More on Wing Structure

Flight Muscles

Insects have either direct or indirect flight. The oldest orders of insects, the Mayflies and Dragonflies have direct flight, where the flight muscles are attached directly to the base of the wings. For these insects, the wings can only beat as fast as the nerves can send impulses to the wing muscles.

All other groups of insect have indirect flight, where the flight muscles attach to the thorax and make it contort and vibrate, which in turn, causes the wings to move. Insects with this method of flight can have a faster wingbeat than those with direct flight.

Wingbeats

Here is a table of wingbeats per second (wps) for some groups of insects from the book, Borne on the Wing by Stephen Dalton. One wingbeat is the full up and down cycle. It also shows the number of metres covered, per second. There is quite a difference!

  • Medium butterflies, 8-12 wps, 2-4 metres
  • Damselflies, 16 wps, 1-2 metres
  • Scorpion flies, 30 wps, 0.5 metres
  • Large dragonflies, 25-40 wps, 7-15 metres
  • Cockchafer beetles, 50 wps, 3 metres
  • Hawk moths, 50-90 wps, 5+ metres
  • Hoverflies, 120 wps, 3-4 metres
  • Bumblebees, 130 wps, 3 metres
  • Houseflies, 200 wps, 2 metres
  • Honey bees, 225 wps, 2-3 metres
  • Mosquitoes, 600 wps, less than 0.5 metre
  • Midges, 1000 wps, less than 0.5 metre

Hemolymph

The network of veins running through all insect wings, provides a structure which supports the wing membranes. The veins also serve a number of other purposes.

The 'hemolymph', the equivalent to insect blood, which runs through these veins, brings oxygen and nutrients to the wings and keeps them hydrated.

The membranes of the wings are lifeless but the veins and surrounding membrane are alive and need to be sustained with oxygen, water and nutrients. Water is needed to retain the wings' flexibility and toughness, otherwise they would dry out, like museum specimens.

Some insect groups, such as dragonflies and butterflies, always keep their wings open but many, like beetles, grasshoppers and bugs fold down the wings when they are at rest. When these insects open their wings, by a spring mechanism, hemolymph is pumped back into the wing veins so they regain their rigid structure. When they close their wings, to fold under a wing case or collapse down flat against the body, the hemolymph is drawn back into the thorax. Changes in the 'hemolymph' levels during flight, may also be used to affect the aerodynamics of the wings.

The wings fold down like a flattened parachute, along specific fold lines; they always fold back in exactly the same way. They need to be sure of unfurling and stretching back out again, with 100% accuracy, within a split second. There is a little paperback activity book called: 'How do insects fold and unfold their wings?' by Robin Wootton, if you are interested!

The organs which control the movement of hemolymph into and around the wings are located underneath the 'scutellum', the triangular cover immediately behind the thorax, in the middle of the abdomen.

Breathing Tubes

Inside each of the wing veins is a 'trachea' or air tube, which leads back to breathing holes or spiracles, on the insect's body or legs.

Sense Organs

Insects have a surprising number of sensory organs on the wings. The most important sense organs are the mechanoreceptors which respond to touch and changes in pressure or vibration. These are used to help with the control of wing movement and stabilising the body, during flight.

Butterflies, for example, have been shown to have a number of special sensory hairs and scales spread out along the outer edges of both wings. These react to changes in airflow and feedback information during flight. The scales and hairs which run along the wing veins also connect to the nerves.

Flies have many sensory receptors on the halteres, which help with balance.

Some moths and butterflies have auditory 'tympanae', or organs, in the veins on the forewing, which react to sound. They look like a small swelling on the vein. (Many families of moth have these organs on their abdomen.) For moths, these organs are sensitive to the ultrasound clicks of bats, when they echolocate. These auditory organs vary for different families of moth and appear to have evolved to tune in to the frequencies, used by the specific species of bat, which prey on them.

Along the edge of some insect wings, e.g. cockroach and blowfly, are several gustatory, or taste, organs which react to different chemicals. It is thought these organs could help insects find a good supply of food.

Some exotic butterflies have been found to have thermo, or heat, receptors on the wing. They close their wings if a direct light source is shone consistently at certain spots along the wing. This would be a useful reaction to avoid over heating.

The nerves for all these sensory organs run through the wing veins and back into the ganglia, or nerve control, in the thorax and head.

System for Naming Wing Veins

There is a recognised system for naming the various veins on insect wings. (The veins follow a similar pattern for all types of insects.) It is called the Comstock-Needham system after John Comstock and George Needham, who devised the system in 1898. It is essential for scientists to be able to identify the specific veins, branches and cross veins because often differences in vein structure is the way to identify different species or families.

Naming of wing veins. Diagram from Wikipedia, Insect Wing Veins

Below are the names of the main veins, which branch as they spread out across the wing. These branches and the cross veins all have specific terminology.

  • C=Costa -red
  • S=Subcosta -orange
  • R-Radius - grey
  • M=Media -green
  • C=Cubitus - blue
  • A=Anal - purple

The wing veins are thicker, stronger and more tightly packed near the front or leading edge of the wing. At the rear of the wing, the veins have branched and are thinner. This makes the insect wing an airfoil, perfect for cutting through the air and reducing drag. The wings have a rounded leading edge which is thicker at the front than the back, like airplane wings.

Conclusion

I hope you have enjoyed this exploration of insect wings and will look more closely next time an insect buzzes past you, in the sunshine!

Photographer, Collector & Wildlife Educator

I am Susanna Ramsey and I have a unique collection of natural history objects relating to British Wildlife. Over the last ten years, I have assembled an extensive range of skulls, skeletons, bones, skins, feathers, wings, antlers, insect specimens and taxidermy, all from animals in the UK.

During 2010-2018, I took my Nature Collection into local primary schools to display and run workshops for the children, linking the exhibition to science topics in the National Curriculum such as Adaptations, Bones, Classification, Food Webs, Habitats, Life Cycles and Local Wildlife.

In 2018-2020, I worked with the leading schools' catalogue, TTS ,to create a range of Educational Resources for primary schools, nurseries, after school clubs and families. To find out more about these products, see below.

I am passionate about encouraging children and adults, to discover the beauty of our local wildlife.

Black darter dragonfly

Sources of Information

Exhibits and Thanks

Over the years, I have been lucky enough to be a regular visitor to the Angela Marmont Centre (AMC) for UK Biodiversity at the Natural History Museum, London. The unimaginably-vast collection of British insect specimens, stored in row upon row, of metal, floor-to-ceiling cabinets has been a massive inspiration to me. There is something infinitely satisfying about the way every species has its own box, within a drawer, within a cabinet and that each can be found within minutes, by the care and expertise of the staff. To witness the incredible number of UK species of moth, beetle, butterfly, fly, grasshopper etc, is simply mind blowing and I feel so privileged to be able to visit and photograph some of the specimens! Many of my photos of UK insect specimens, in this presentation, have been taken here.

I have used the photo stacking equipment at the Angela Marmont Centre to take highly-detailed photos of some of the specimens to put into slideshows for my primary school workshops. When I was young, I always wanted to be an archaeologist and it was my ambition to work in a museum; to sit in the Centre, using the equipment and handling the specimens, listening to the chatter of the experts at work, has been a dream come true. I am so grateful to the staff at the Centre for their encouragement and for always making me feel so welcome.

I usually focus only on local British wildlife but I must admit to having a collection of stunningly colourful and exciting insect specimens from exotic countries too, in The Nature Collection. They are so beautiful and to photograph them under a microscope lens or just to take macro images, is a huge source of joy. The insect specimens have largely been bought at the annual Amateur Entomolgy Society (AES) Fair at Kempton Park, held in early October. It is a mind blowing event to visit! Great for families.

For non-insects, almost all of the animals in my Nature Collection were either found by myself, Susanna Ramsey, or donated by friends and family to The Nature Collection, as an educational resource. Huge thanks for all the tiny, carefully-wrapped bundles of feathers and bones, to Steve and Sam Read, John Lock, Chris Matcham, Franko Maroevic, Tim Howard, Jan Wilczur, Simon Richards, Peter Veniard, Paula Redmond, Phil Davis, Bob & Sally Black, Jo & Frank Sheppard and Katie Ramsey. Many of these people are naturalists and experts in their field; I am indebted to them too, for all that they have taught me about our local wildlife.

BRITISH WILDLIFE PRODUCTS

If you know children who are interested in nature, are a teacher, or would like to learn more about British Wildlife yourself, explore the range of British Wildlife products recently created by The Nature Collection and the leading schools' catalogue, TTS.

The products are perfect for use in primary schools, nurseries, after school clubs, forest schools or at home with friends and family. Click on the links below to find out about each product.

Look & Learn Cards: British Birds, Mammals, Minibeasts

Food Webs Activity Pack

Classification: British Wildlife & Natural History

Identification Wheels: British Birds, Mammals & Minibeasts

Discovery Bags: British Birds, Mammals, Minibeasts

Playground Signboards: Birds, Mammals, Minibeasts

Birds ID Wheel, Food Webs pack, Mammal Look & Learn cards
Created By
Susanna Ramsey
Appreciate

Credits:

Susanna Ramsey