Butter by Na Eun

Butterflies

Edited by Na Eun Kwon

Contents

Introduction 09 Origin and Structure of Butterflies

Life Cycle and Metamorphosis

Families of Butterflies and Moths

Flashcards 85 Bibliography 92 Image Sources

Introduction

As far as the general public is concerned, butterflies and moths are the best known and possibly the best loved of insects. The splendid colors that often decorate their wings are without doubt the basis for this popularity. The phenomenon of metamorphosis is another reason for their fame since in this group the change can be so spectacular as to become a symbol of transformation itself (“worm” changes into an “angelic butterfly”). Lepidoptera have also been the subject of thousands of scientific papers, and they continually offer experts new areas for research. That more than 3,000 scientific articles were published on them in 1978 gives us some idea of the interest they generate. In addition to this extensive emphasizes the attractiveness of Lepidoptera both to the layman and to the expert. However, if one were to ask the man in the street what he actually knows about these animals, the answer would be brief – a few names, some general facts about their life cycles, and a few curious features of the behavior of a small number of species: the cabbage white, the swallowtails, the processionary moths, the saturnids, and a few others. Consequently this book, which is not just a list of species enlivened by beautiful color plates but an attempt to open a window on a world unknown to most people, is most welcome It does not confine itself to displaying multicolored butterflies and a list of names; instead it explains the biological significance of their coloration, the mechanisms of their evolution and its intimate connection with that of the higher plants, and the causes of the diversity found in animals and discusses the distribution of members of the Lepidoptera.

Origin and Structure of Butterflies

Butterflies and moths are a fairly homogeneous group of insects that forms the order Lepidoptera. The name is derived from the Greek words “scale,” and “wing,” referring to the scales covering the surfaces of the wings; the structure and pigments of these scales are responsible for the extraordinary variety of wing colrs. The insect order Lepidoptera is one of the largest and most important of orders: About 165,000 species have been recognized and described. This figure will inevitably rise in the future as hitherto unexplored regions, where the fauna is still virtually unknown, are investigated and specimens in museums and other public and private collections are reexamined according to new classification criteria. Like all other insects, adult Lepidoptera have a chitinous external skeleton and a body divided into three regions, head, thorax and abdomen. A pair of legs articulates with each of the three thoracic segments – the pro-, meso- and metathoraces – and two pairs of wings are inserted on the meso- and metathoraces. In common with other holometabolous insects lepidopterans develop indirectly and pass through several very different stages, beginning with the egg and followed by the usually eruciform larva, the pupa, and finally the imago or adult. Consequently they undergo complete metamorphosis. The following is a brief diagnosis listing the characteristics that, taken together, distinguish this order from all other insects.Winged with complete life cycle, terrestrail only rarely aquatic, insects, small, medium or large in size, two pairs of membranous wings more or less densely covered by scales; suctorial mouthparts or more rerely, chewing mouthparts in the adult stage; larvae eruciform with mouthparts typically chewing.

Image of Butterfly Fossils

Origin of Moths and Butterflies and Fossil Forms Despite their extraordinary evolutionary diversity and richness â&#x20AC;&#x201C; in the animal kingdom only the order Coleoptera has more descibed members â&#x20AC;&#x201C; the Lepidoptera are, in comparison with other insects, a relatively young group. The Collembola, which many now regard as a separate class, were present as long ago as the Devonian, 350 million years b.p. and the forests of the Carboniferous, dating from 300 million years b.p., were the home of numerous insects, such as dragonflies, including giant one, cockroaches, and grasshopper like forms that were similar to the modern insects. Until a few years ago it was not possible to date the origin of butterflies and moths with any degree of accuracy because of the paucity of fossil remains and almost all came from the

Origin and Structure of Butterflies

Tertiary rocks or amber of the Eocene. 50 milion years old; and that some of them were of butterflies and moths sililar to modern families thought to have been highly evolved suggested that the origins of the group went back further than had been first thought. On the other hand certain finds attributed to the Triassic, which were described as Lepidoptera, have subsequently been recognized as belonging to other insect order. However, series of recent discoveries has shed more light on the evolutionary history of the butterflies and moths: Fossil species belonging to two primitive lepidopteran families have been found in amber from Lebanon and in sedimentary rocks in Siberia. All date from the lower Cretaceous, some 100 to 130 milion years b.p. Two micropterigid fossils in particular, the Siberian Undopterix sukatshevae and the Lebanese Parasabatinca aftimacrai, are very well preserved and leave no doubt as to their exact relationships. From these finds we are now certain that butterflies and moths were present at leat by the early Cretaceous. The first fossils of flowering plants, the anangiosperms, with whose evolution that of the Lepidoptera is certainly bound up, are also from the early Cretaceous. However that the first known angiosperms were already clearly differentiated into forms similar to modern ones suggests that their evolution had actually begun considerably earler, perhaps in the butterflies and moths, whose ancestors should possess characters markedly different from those of modern forms; these characters should appear intermediate to the caddis flies (order Trichoptera), which are generally recognized as the Lepidopteraâ&#x20AC;&#x2122;s closest relatives.

The Body of Butterflies The body form of a butterfly is like no creature in the world. They are beautiful flying animals that have unique characteristics that are unlike any other. As for an insect, they have an exoskeleton with jointed legs and three basic body parts; head, thorax, and abdomen, but the more distinctive characteristics of a butterfly are much more impressive. Butterflies are sometimes known as flying gems because of their beautifully colored wings. If you have ever wondered why the wings appear as they do or how butterflies search and find specific flowers, this is the article to read. antennae

Basic Structure of Butterfly

head

thorax

abdomen

hind wings

fore wings

Origin and Structure of Butterflies

Image of Butterfly’s Eyes

Butterfly Eyes Butterflies and most other adult insects have a pair of spherical compound eyes, each comprising of up to 17000 “ommatidia” - individual light receptors with their own microscopic lenses. These work in unison to produce a mosaic view of the scene around them. Each ommatidium consists of a cornea and cone, which together function as a lens. Emerging from the back of each cone is a rod down which light travels to reach a cluster of 2-6 sensory cells, each of which is sensitive to a particular part of the visual spectrum.The eyes of Skippers are different from those of other butterflies. They have a space between the cones and rods which allows light from each ommatidium to spill into neighbouring

rods, effectively increasing their resolution and sensitivity. As a result Skippers can fly very accurately from one spot to another. This different type of eye structure is one of the reasons why taxonomists place them in a different super-family to all other butterflies - the Hesperioidea. The laws of optics show that itâ&#x20AC;&#x2122;s likely that everything from about one centimetre to 200 metres will be rendered in sharp focus by butterflies, as their ommatidia are of very short focal length.The butterflyâ&#x20AC;&#x2122;s brain can instantly detect whether the image formed by each ommatidium is dark or light. If a predator approaches or if the butterfly moves its head a tiny fraction, the amount of light hitting each receptor changes instantly because of itâ&#x20AC;&#x2122;s very narrow angle of view. This sensitivity to changes in its surroundings means that a butterfly is extremely efficient at detecting movement and at gauging the distance of an approaching predator, enabling it to take immediate evasive action. The sensitivity to changes in their visual field, combined with a high flicker-vision frequency of about 150 images per second, may also help butterflies to piece together the thousands of elements of the mosaic image produced by the compound eye. It is not known whether butterflies and other insects are able to merge these mosaic elements into a single image. If are able to do so, it would render them capable of distinguishing patterns at close distances. Vertebrates need to move their eyes and heads to scan their surroundings, but the compound eyes of butterflies provide them with almost 360 degree vision. They can see everything at the same time, so they can accurately probe into flowers in front of them, and at the same

Origin and Structure of Butterflies

time devote equal concentration to detecting threats from behind. Butterflies can see polarized light, enabling them to determine the position of the sun, even when it is partly hidden by cloud. This lets them relate their position to the sun and use it as a compass when moving around their habitats. Humans and birds perceive colours in a different way to butterflies, as the latter are ultra-sensitive to UV as well as visible radiation. Flowers have ultra-violet patterns that are invisible to humans but which can be recognised by butterflies. These UV patterns guide butterflies to the source of nectar in much the same way that runway lights guide an aircraft in to land. Experiments on Colias butterflies dyed orange, red, green, blue and black have shown that females don’t discriminate between males of different colours. Most biologists agree that visible colours and patterns are NOT used for butterfly-to-butterfly communication. Their primary function is to convey survival-related signals to birds ( i.e. camouflage, aposematic colour, mimetic patterns etc ). Butterflies can communicate with each-other visually, but they use a “private channel” of ultraviolet patterns which are overlaid on the visible patterns, and cannot be seen by vertebrates. They enable butterflies to recognise conspecifics during the initial “approach” phase of mate location. It has been proven by experimentation that males which have had their UV-reflecting patterns obliterated suffer a significant drop in mate-location success. As well as being sensitive to UV patterns, butterflies are also alert to the iridescent colours produced when sunlight refracts from the wings of other butterflies. Many species have also evolved selective colour response, i.e.

they are â&#x20AC;&#x153;tunedâ&#x20AC;? to react to colours that are dominant in the wing patterns of their own species. Examples include Heliconius erato which is sensitive to red, Morpho helenor which reacts very strongly to blue, and Philaethria dido which is responsive to green. Male butterflies will intercept and chase any insect of approximately the same size and colour as the female of their own species during the approach phase of mate-location. Experiments using dummy cardboard females have however shown that males respond equally to square, circular, triangular, or buttefly shaped dummies. Females of some species however seem capable of recognising plants purely on the basis of leaf-shape and colour. This ability varies from one species to another, and is most highly developed in monophagous butterflies - those whose larvae will only eat one type of plant. Polyphagous butterflies ( those which utilise several families or genera of larval foodplant ) tend to rely almost exclusively on chemical cues. I have e.g. often observed Pieris napi females searching for oviposition sites. They alight momentarily on various plants, sampling each by puncturing the leaf cuticle with spurs on the legs, to release chemicals in the leaf which are then tasted using the olfactory receptors in the feet. Leaves which were tested included bracken, ivy and oak leaves, all of which are very different in shape from the crucifers needed for oviposition. This appears to indicate that in this species sight plays little or no role in selecting plants for egg-laying.

Origin and Structure of Butterflies

Elephant Hawkmoths Deilephila elpenor have been studied to determine whether or not nocturnal moths can perceive colour. It seemed unlikely, but Kelber et al found that this species has 9 light receptors in each ommatidium (compared to between 2-6 in butterflies); and used behavioural experiments to prove that the moths can discriminate coloured stimuli at intensities corresponding to dim starlight. Insects are unable to blink, so need other ways to protect their eyes. In many butterflies and moths the eyes are shielded by the labial palpi, which act as dust filters. Butterflies in the Satyrine genus Lethe have a dense layer of fine setae or â&#x20AC;&#x153;hairsâ&#x20AC;? on their compound eyes. Studies by the author of these butterflies in Sri Lanka and Borneo indicate that they are strongly attracted to wet dung, and spend long periods probing into it. It seems plausible therefore that the setae could function in the same way as a catâ&#x20AC;&#x2122;s whiskers, acting as tactile sensors that warn them when their eyes get too close to the dung, which would blind them if it stuck to the eye surface. Antennae From between the eyes emerge a pair of segmented antennae. These can be voluntarily angled at various positions, and are best thought of as a form of radar. They have many functions including pheromone detection, which is used for mate location and recognition. The antennae of Monarchs Danaus plexippus are covered in over 16000 olfactory ( scent detecting ) sensorssome scale-like, others in the form of hairs or olfactory pits. The scale-like sensors, which number about 13700 in total, are sensitive to sexual pheromones, and to the honey odour which enables them to locate sources of nectar. Butterfly antennae, like those of ants and bees

Essex Skipper Thymelicus lineola ( England ) frontal view of antennae

Origin and Structure of Butterflies

may also used to communicate physically - e.g. it is common to see male Small Tortoiseshells Aglais urticae drumming their antennae on the hindwings of females during courtship, possibly to “taste” pheromones on the female’s wings. Similar activity can be found in Wood Whites Leptidea sinapis and many other species.

Butterfly Close Up

Butterflies are often observed “antenna dipping” - dabbing the antennal tips onto soil or leaves. In this case they are sampling the substrate to detect it’s chemical qualities. They do this to establish whether soil contains essential nutrients. Male butterflies often drink mineralised moisture to obtain sodium, which they pass to the females during copulation.

The antennae of Monarchs Danaus plexippus are covered in over 16000 olfactory sensors - some scale-like, others in the form of hairs or olfactory pits. The scalelike sensors, which number about 13700 in total, are sensitive to sexual pheromones, and to the honey odour which enables them to locate sources of nectar. Butterfly antennae, like those of ants and bees may also used to communicate physically - e.g. it is common to see male Small Tortoiseshells Aglais urticae drumming their antennae on the hindwings of females during courtship, possibly to “taste” pheromones on the female’s wings. Similar activity can be found in Wood Whites Leptidea sinapis and many other species. Butterflies are often observed “antenna dipping” - dabbing the antennal tips onto soil or leaves. In this case they are sampling the substrate to detect it’s chemical qualities. They do this to establish whether soil contains essential nutrients. Male butterflies often drink mineralised moisture to obtain sodium, which they pass to the females during copulation. Butterfly antennae are always clubbed at the tips. In most butterfly subfamilies e.g. Nymphalinae, Heliconiinae and Pierinae the shaft is straight and the club very pronounced, but in the Ithomiinae the antennae thicken progressively towards the tip. The clubs of Skippers (Hesperiidae) taper to a fine point and are hooked at the tip, but most other butterflies have rounded ends to the clubs. Some moths including Burnets (Zygaenidae) and Cane Borers (Castniidae) also have antennae that are clubbed just like those of butterflies. This is one of many reasons

Origin and Structure of Butterflies

why the “convenience” division of Lepidoptera into butterflies and moths is difficult to justify scientifically. Male moths from the Saturniidae, Lasiocampidae and a few other families have plumed “pectinate” antennae which are covered in tens of thousands of olfactory sensors, and can detect the scent of females from distances of up to 2km away. The females have no need to detect pheromones, so their antennae, although similar in structure, have very much shorter plumes. At the base of the antennae is a “Johnston’s organ”. This is covered in nerve cells called scolopidia, which are sensitive to stretch, and are used to detect the position of the antennae, as affected by gravity and wind. Thus they are used to sense orientation and balance during flight, and enable the butterflies to finely adjust their direction or rate of ascent / descent. It is also thought possible that they are able to detect magnetic fields when migrating. 6-spot Burnet Zygaena filipendulae. Burnet moths have antennae that are clubbed

Palpi Protruding from the front of the head are a pair of small projections called labial palpi, which are covered in olfactory ( scent detecting ) sensors. Similar sensors are also located on the antennae, thorax, abdomen and legs. These sensors are present in a variety of forms, and it is likely that each type fulfils a different role. Sensors on the antennae for example might be “tuned” to locate sexual pheromones, while those on the legs may be sensitive to chemicals exuded by larval foodplants. Logic would indicate that those on the labial palpi and proboscis, due to their position, might be tuned to detect adult food sources such as nectar, urine, carrion or tree sap. Alternatively it is possible that they might function to detect the “smell” of air which emanates from particular

locations - incoming dry desert air for example might be detected and act as a trigger to stimulate migration. Some biologists argue that in addition to their olfactory functions, palpi have other functions such as shielding the proboscis. Logically this would mean a short proboscis would be associated with small palpi, and a long proboscis associated with larger palpi. In fact this is not the case - species with very long proboscises, such as Saliana skippers and Eurybia Underleafs have average sized palpi, while Libythea Beaks and other species with prominent palpi have unremarkable proboscises. Another theory is that the palpi may serve as dust filters to protect the surface of the eyes. DeVries states that the most well developed palpi are found in butterflies which feed as adults on rotting fruit or dung where there is a greater probability of soiling the eyes or becoming infested with mites. This theory however doesn’t hold true for Libythea Beak butterflies which have extremely long palpi but which feed at flowers, or in the case of males at mineralised moisture at the edge of puddles.

Image of Butterfly’s Palpi

Proboscis The proboscis consists of a pair of interlocking c-section channels that when linked together form a tube, much like a drinking straw. This tube can be coiled up like a spring for storage, or extended to enable the butterfly to reach deep into flowers to suck up nectar. If the proboscis gets clogged with sticky fluids the 2 sections can be uncoupled and cleaned. Olfactory sensors near the tip of the proboscis and in the food canal, together with similar sensors on the tarsus and tibia of the legs, enable butterflies to “taste” nectar, pollen, dung and minerals. In temperate zones most butterflies obtain their sustenance by sucking nectar from flowers. There

Origin and Structure of Butterflies

are exceptions however - male Purple Emperors Apatura iris for example never visits flowers; they feed entirely on fluids which they obtain from sources including dung, carrion, urine-soaked ground, tree sap and honeydew ( aphid secretions ). In the Alps and Pyrenees mountain ranges of Europe males of many species, particularly Lysandra, Pyrgus, Thymelicus, Cupido & Mellicta often aggregate in groups of several dozen ( and sometimes several hundred ) to imbibe mineralised moisture from the edges of puddles, urine-soaked ground or cattle dung. This phenomenon is common in alpine regions throughout the northern hemisphere. In the tropics the majority of males from all families follow the behaviour described above for the Purple Emperor. Females of some species appear not to feed at all, and rely on proteins and amino acids transferred via the sperm of males during copulation. In the case of Papilionidae, Pieridae and Lycaenidae however females commonly obtain sustenance from flower nectar. In Central & South America female Heliconius butterflies visit Lantana and various other flowers for nectar. They also sequester pollen from Psiguria, Anguria and Gurania flowers in the rainforest. The pollen collected from the flowers is processed by the females to extract amino acids which increase longevity and enable them to produce eggs for up to 9 months. The butterflies have acquired the ability to learn and remember the locations of individual pollen plants. They visit these every day, following a predefined circuit through the forest.

â&#x20AC;&#x153;BDâ&#x20AC;? butterfly Callicore cynosura, using its proboscis as a straw to imbibe dissolved minerals from the surface of a damp rock on the shore

Origin and Structure of Butterflies

Thorax The thorax consists of 3 body segments which are fused together, forming a chitinous cage which contains the flight muscles, and acts as an anchor point for the legs. Within the thoracic cavity of flying insects are very powerful muscles which lever on the wings. The rapid expansion and contraction of the muscles causes the wings to rise and fall at rates of up to 1000 beats per second in bees and hoverflies, and about 200 beats per second in hawkmoths. Image of a butterfly, focussed on thorax

Amongst the butterflies, Skippers have the fastest wing beats. Their wings whirr audibly at a rate of about 20 beats per second as the butterflies dart rapidly from place to place. Other butterflies such as Swallowtails, Pierids and Satyrines can only manage about 5-10 beats per second. Slower still are the Ithomiines which have very deep beats at about 4 per second. Slowest of all are the Caligo Owl butterflies which struggle to achieve more than 2 or 3 beats per second. Legs All adult butterflies have 3 pairs of legs, except in the Nymphalidae and in males of certain other groups, where the front pair are reduced to brush-like stumps and modified as chemoreceptors.

Image of a butterfly

The tibia of each leg has a subgenual (under the knee) organ, which detects and amplifies small vibrations. This alerts butterflies to ground vibrations caused by the approach of animals or birds, enabling them to respond instantly to danger. In most cases they take flight flight, but some species such as the Peacock Inachis io and Bullseye moths Automeris randa react by suddenly flashing open their wings to display â&#x20AC;&#x153;false eyeâ&#x20AC;? mark-

ings that startle the predator. The tibia on the forelegs of Pieridae, Hesperiidae, Papilionidae and Lycaenidae are often equipped with a flexible spur through which the antennae can be drawn for cleaning. The spur also functions as a spike with which a female can puncture the cuticle of a leaf, causing it to bleed minute quantities of chemicals. The butterfly then checks the chemical composition of the leaf, using olfactory sensors on her legs and feet.

Image of a butterfly

Origin and Structure of Butterflies

Abdomen The abdomen contains the digestive system, breathing apparatus, a long tubular heart, and the sexual organs. The abdominal exoskeleton is multi-segmented. Each of the 10 segments is comprised of a ring of a hard material called chitin. The segments are linked by flexible tissues, allowing the abdomen to bend, a necessity for copulation and egg-laying. The genitalia are at the tip of the abdomen. Each species has uniquely shaped genital armature - the male “key” only fitting the correct female “lock”. Because the armature is unique to each species, taxonomists have traditionally relied heavily on microscopic examination of genitalia to determine species and their relationship with other taxa. The advent of DNA analysis and advances in phylogenetics however now mean that genitalia study is just one of many techniques adopted. Females are equipped with an ovipositor, used to release and deposit the fertilised eggs. In most species this is short and not normally visible, but in certain moths it is modified into a long “sting-like” tube so that the eggs can be inserted into chinks in the bark of trees. The males of many neotropical Arctiid moths, including Creatonotos transiens possess at the tips of their abdomens an extraordinary eversible organ called a coremata. An unmated female “call” to males by releasing pheromones from the tip of her abdomen. Males are attracted by the scent and arrive on the scene, forming a lek, often comprising of a dozen or more individuals. Experiments have demonstrated that males which have accumulated plant-derived pyrrolizidine alkaloids (PAs)

then respond by everting their coremata and releasing pheromones. The PAs are passed to females in a spermatophore during copulation, conferring them with toxic qualities that protect them from predation, and also increasing their longevity and fecundity. Captive males that have been deprived of PAs do not evert their coremata or release pheromones. It seems likely therefore that the females are able to select which males to mate with on the basis of the strength of their pheromones - i.e. choosing the male with the highest PA delivering ability. On the sides of each segment are microscopic holes called spiracles, through which air enters and leaves the body. Slight rhythmic movements of the body, coordinated with the opening and closing of the spiracles, causes air to be drawn into tiny lung-like sacs, and later expelled. Butterflies feed exclusively on liquids which may according to species include nectar, dissolved pollen, mineralised water, liquefied dung, urine, sweat, bodily fluids from decomposing animal corpses, and in some cases even tears from the eyes of alligators ! After digestion and extraction of proteins and other minerals the waste matter is expelled from the anus either in liquid form, or as tiny faecal pellets. Insects such as cicadas and grasshoppers are well known for producing courtship songs, but most people only associate other insects with â&#x20AC;&#x153;incidentalâ&#x20AC;? sounds such as the buzzing of wings. There is a great deal of evidence however that insects in general, including lepidoptera, produce sounds that fulfil a variety of functions.

Origin and Structure of Butterflies

Many of these sounds are beyond the range of human hearing, and can only be detected with specialised acoustical equipment. In some butterflies however the sounds are clearly audible.Hamadryas butterflies can produce a crackling sound by twanging 2 tiny prongs on the tip of their abdomens against bristles on the valvae. This is discussed further on the next page. Nocturnal moths are commonly preyed upon by bats, which project a series of ultrasound clicks and listen to their echoes in order to locate flying moths. Many moths have developed “ears” on their wings or thorax which can alert them to approaching bats, enabling them to take evasive action. The neotropical tiger moth Bertholdia trigona goes a stage further - it actively jams the bats “radar” by producing its own ultrasound, by vibrating a tympanal organ located on its metathorax. Some butterflies, including the Hamadryas Crackers and Heliconius Longwings can detect sound, using an “ear” near the base of the underside of their wings. The ear can only be seen with the aid of a powerful microscope. It takes the form of a funnel shaped sac, covered with a very thin membrane. This vibrates in response to high frequency sound, and stimulates nerve cells called scolopidia, which send a message to the butterfly’s brain. Hamadryas butterflies use their ears to detect crackling noises made by territorial males. The sound is made by twanging 2 tiny prongs on the tip of the abdomen against bristles on the valvae. Males habitually bask on tree trunks, where they wait to intercept passing females. It has been speculated that the sound might deter competing males from occupying the same territory but this seems to be unlikely as a single tree trunk will often host 3-4 males perching in close proximity. It seems

more likely that the sounds act act as a trigger to initiate responses from females during courtship. Kathleen Lucas of the University of Bristol used a laser beam to scan the membrane of the eardrum of Morpho peleides ( = helenor ). She found that lower frequencies between 1000 - 5000 Hz caused vibrations to focus on a spot on the outer membrane, but that frequencies above 5000 Hz caused the entire membrane to vibrate, including the â&#x20AC;&#x153;fried eggâ&#x20AC;? dome structure arrowed in the photo. Moth ears respond equally to all frequencies, but Morpho butterflies seem able to differentiate between low and high pitched sounds. Lucas speculated that this could help the butterflies figure out if birds are about to attack. If e.g. they could tell apart the sounds of flapping bird wings and those of bird song, it might trigger different escape responses by the butterfly. Some scientists believe that when butterflies first evolved they were nocturnal, and that their ears originally served to detect and avoid predatory bats. Bats emit acoustic pulses when flying at night, and use their highly sensitive ears to detect the echo reflected back by solid objects. This way they avoid hitting unseen obstacles, and are able to locate moving prey in the dark. Noctuid moths ( and certain other groups ) are able to hear a batâ&#x20AC;&#x2122;s acoustic pulses. The frequency and volume enable the moth to detect how far away the bat is. Furthermore the relative positions of the moths hearing organs enable it to determine the direction of approach. The moth initially reacts by steering away from the bat, but if it gets within striking distance the moth instantly dive-bombs to avoid being eaten.

Origin and Structure of Butterflies

Wings All butterflies and moths ( except Plume moths ) have 2 pairs of overlapping wings, each comprised of a very thin double membrane with rigidity supplied by a network of tubular veins which radiate from the base of the wings. The pattern of veins is different for every genus of butterfly, and is one of the main criteria used by taxonomists when classifying butterflies. Vein structure of a transparent Satyrine butterfly

The wing membranes are transparent, but are partially or fully covered in a dust-like layer of tiny coloured scales. Each scale comprises of a flat plate arising from a single cell on the wing surface.The scales vary considerably in shape, some being rectangular, while others are shaped like tear-drops or plumes. An individual scale might typically measure about 50 microns across ( 1/20 of a millimetre ) and be 100 microns long, although many are hair-like, and are very much longer. There can be as many as 600 individual scales per sq millimetre of wing surface, although in certain genera such as Acraea, Aporia and Parnassius the density is considerably lower, giving the wings a translucent appearance. large areas of the wings, resulting in almost complete transparency. There a 3 basic types of scale - pigmentary scales, structural scales, and androconia. Pigmentary scales are mostly flat. Their colour is the result of the presence of melanins, pterins and other chemical pigments, most of which are sequestered from the larval foodplants and passed to the adult butterflies. The pigments account for the basic colours found in butterfly wings - black, red and yellow. The juxtaposition of the various coloured scales, and the amount of pigment they each contain, can create the illusion of additional colours such as orange, cream and green.

proboscis costa

apex

termen

tornus

dorsum

apex

tornus

termen

From Top to Bottom A female Brimstone Gonepteryx rhamni, seen here extending itâ&#x20AC;&#x2122;s proboscis to suck up nectar from a thistle flower Catoblepia berecynthia, wing scales, magnification x10

Life Cycle and Metamorphosis

Evolution of the 4-stage lifecycle Insects first appeared on Earth in the late Silurian Period. The earliest insects had a simple 2-stage lifecycle in which miniature versions of the wingless adults emerged from eggs. Such insects are called Apterygotes. Modern day examples include silverfish, springtails and bristletails.Winged insects probably first appeared in the late Devonian or lower carboniferous Period, when a 3-stage Exopterygote lifecycle evolved. In this case wingless nymphs emerge from eggs. As the nymphs feed and grow they periodically moult their skins. The stages between the moults are called instars. During the later instars the nymphs develop wing “buds”, but it is not until the final moult that fully developed wings are present. Examples of Exopterygotes include mayflies, dragonflies, stick and leaf insects, katydids, mantises, earwigs, cockroaches, lice, termites and shield bugs. The most advanced insects, i.e. those with a 4-stage lifecycle, evolved in the late Carboniferous Period. These are known as Endopterygotes, examples of which include lacewings, scorpion flies, caddis flies, true flies, fleas, bees, wasps, ants, sawflies, beetles, butterflies and moths. The lifecycle of butterflies was first unravelled in 1600 by Maria Sibyella Merian, who observed that they have 4 distinct phases of development : ovum, larva, pupa and imago ( adult ). Each stage of the lifecycle is sharply differentiated from the last but is ontogenetically dependent on it. Individuals carry genes which govern development at each stage of the lifecycle but different genes come into play at each stage. Adult butterflies for example carry caterpillar genes that are “switched off” and vice versa. Mutant genes control features that

Butterflyâ&#x20AC;&#x2122;s Life Cycle

are only present during part of the lifecycle e.g. only adult butterflies have antennae, wings and a proboscis. Behavioural features such as mate location, copulation and migration are also controlled genetically by these mutant genes.

Life Cycle and Metamorphosis

STAGE 1: Egg The shape, size, colour and texture of butterfly eggs varies greatly from one species to another. Eggs of Satyrines and Heliconiines are typically domed or barrel-shaped, adorned with between 8-30 vertical ribs, between which can be seen dozens of lateral ridges. Most Hesperiidae, Papilionidae and Riodinidae produce smooth globular eggs. The eggs of Polyommatines have a finely reticulated surface, and are shaped like flattened do-nuts. Pierines produce tall skittle-shaped eggs, with fine vertical ribbing. All butterfly eggs have a depression at the top, in the centre of which is a hole called the micropyle, through which sperm enters during fertilisation.The egg shell also is peppered with thousands of microscopic pores called aeropyles. Microscopic examination of the eggs of Riodinidae, Lycaenidae and Limenitidinae species reveals them to be adorned with hundreds of minute hexagonal pits. Tiny hollow spines emerge at the intersections of each hexagon. These are also aeropyles, and act as breathing tubes for the developing larva. Fertilisation In the case of Nymphalidae and most other butterflies the eggs are already formed within the body of females when they emerge. They grow in size over a period of 2 or 3 days as they mature within the femaleâ&#x20AC;&#x2122;s abdomen. Egg-laying is triggered when they reach a certain size, at which time they pass from the ovariole to the egg chamber. They are fertilised just prior to egg-laying, the maleâ&#x20AC;&#x2122;s sperm having been stored until this time within a receptacle in the female abdomen.

Life Cycle and Metamorphosis

Oviposition Butterflies lay their eggs either singly or in batches, on or near the foodplants that will be used by the caterpillars. Many species lay their eggs away from the foodplant, on dry grass stems, dead leaves or even on soil. This strategy prevents the eggs from being accidentally devoured by grazing animals. It also makes it more difficult for parasitoid wasps and flies to locate the eggs.

Image of Searching for Eggs

Some species, e.g. the Marbled White Melanargia galathea, drop their eggs randomly as they fly amongst tall grasses, but most species have very precise requirements. Pearl-bordered Fritillaries Clossiana euphrosyne for example lays their eggs singly on dead bracken or dry grass stems that are within a metre of their caterpillar’s foodplant, dog violet. The White-letter Hairstreak Satyrium w-album is even fussier, always laying it’s eggs on elm twigs, at the precise point where the new year’s growth and old growth meet. Silver-washed Fritillaries Argynnis paphia lay their eggs in chinks on the bark of oak trees, but the larvae don’t eat oak - they begin by eating their own egg-shells, and then go into hibernation until the following spring, when they descend the tree trunks to feed on the leaves of nearby violets.

Caterpillar Ready to Emerge from Egg

In the tropics eggs are often glued underneath the leaves of trees and bushes where they are protected from rain and from the desiccating effects of hot sunshine. In the Amazonian rainforests Heliconiine butterflies often lay their eggs on Passiflora tendrils, presumably to place them as far out of the reach of marauding ants as possible.

Orange tip caterpillars Anthocharis cardamines normally feed on cuckoo flower or garlic mustard leaves, but if they encounter another caterpillar they become cannibalistic. It would therefore be wasteful if more than one egg was laid on each plant, so the butterflies have evolved the ability to detect eggs that have already been laid by other females. Studies have shown that many members of the subfamilies Pierinae, Heliconiinae, Danainae and Papilioninae have this ability, and avoid laying on plants carrying eggs laid by other members of their own genus or species.

Image of Egg Batch

Life Cycle and Metamorphosis

STAGE 2: Larvae A larva has only 2 functions during it’s life - to eat and survive. It’s basically just an eating machine with large powerful jaws, a huge gut, and a highly elastic skin that stretches to accommodate the huge amount of food consumed. Larvae do not possess external wings. Even the tiniest larvae however have rudimentary wing-pads under their skin. These are initially extremely small, but by the time the larvae are fully grown the wing pads have developed veins and other structural features found in adult butterflies. All butterfly larvae have six true legs located on the first 3 segments. These legs are used primarily for holding and manipulating the leaves on which they feed. On the abdominal segments they have 4 pairs of false legs called prolegs. These “walking” legs operate by hydraulic pressure. Each has a rosette of microscopic hooks around its base, which enable the larvae to maintain a strong grip on twigs or leaves. There are also a pair of gripping anal claspers at the tail end of the body, which are used to secure the caterpillar while the prolegs are doing the walking.

Life Cycle and Metamorphosis

Anthocharis Cardamines - The Egg on the Right is Freshly Laid

Hatching Most butterfly eggs undergo colour changes as the young larvae develop within them. The eggs of the Marsh Fritillary Euphydryas aurinia for example are pale yellow when first laid, but after a day or two turn pinkish-brown, then deep crimson, and finally dark grey just before the larvae hatch. The eggs of the Orange tip Anthocharis cardamines are pure white when first laid, but turn orange within 2-3 days, then become dull grey when hatching is imminent.

Feeding For the remainder of the larval stage most species feed on the leaves, stems, flowers or seeds of particular plants. Some species are polyphagous, i.e. they are adapted to feed on a wide variety of plants from different botanical families. Most however are monophagous, i.e. limited to feeding on just one or two closely related plant species, and unable to survive on anything else. Many species in the family Lycaenidae are carnivorous, feeding on ant grubs or aphids.

1st instar Spilosoma Luteum Larva Nibbling Tiny Holes in the Lower Cuticle of Leaf

Larvae and adult butterflies of any given species generally use different sources of food. Marsh Fritillary caterpillars for example eat the leaves of devilâ&#x20AC;&#x2122;s bit scabious, but the adult butterflies feed on the nectar of buttercups, milkworts and thistles. In temperate areas the larvae and adults live at different seasons, but in the tropics the 2 stages often co-exist at the same time of year, so the dichotomy between larval and adult feeding behaviour enables them to avoid competing for food.

Life Cycle and Metamorphosis

Moulting Depending on the species, caterpillars increase their body weight between about 60-200x in the period between hatching and pupating. Accordingly as it feeds and grows, a caterpillar’s elasticated skin periodically becomes too tight and has to be moulted and replaced with a looser baggy elastic second skin that forms under the outer skin. Moulting is triggered by nerve cells called scolopidia, which detect stretch in the skin between the caterpillar’s segments.Two or three days before moulting caterpillars anchor themselves either to a small button of silk which they have spun on a leaf or twig; or to a silk web spun over the foodplant. A day or two prior to moulting the soft tissues within the caterpillar’s head retract, forming a new head capsule which is temporarily housed within the first thoracic segment. When moulting takes place the old head shell slides forward and drops off. The old skin then splits just behind the head, allowing the caterpillar to walk forward out of its former costume. At first the new skin is loose and soft, leaving the larva highly vulnerable to attack by parasitoid wasps and flies. The larva slowly inflates it’s body by drawing in air through the spiracles. After a couple of hours the larva’s mandibles ( jaws ) have hardened, at which point a larva will often eat it’s old skin. Another 2 hours or so later the skin has toughened sufficiently to allow the larva to walk about without injuring itself, and to resume normal feeding. The stages between moults are known as instars. Caterpillars of the family Lycaenidae usually have 4 instars. Those of the Hesperiidae, Nymphalidae and Pieridae usually have 5 instars. The Riodinidae have between 6-8 larval instars according to species.

Larva After Its Last Moulting

Sexual development As larvae grow and mature they begin to develop sexual organs internally, but it is not possible to determine the sex of a larva from its external appearance. There are however some species of Lepidoptera in which the larvae that will ultimately become males have 4 instars, while those that will become females have 5 instars. The male moth looks much like any other moth, but the female is wingles.

Life Cycle and Metamorphosis

STAGE 3: Pupa When a larva becomes full grown, it undertakes a final moult to become a pupa. For a day or two prior to pupation the larva goes through a wandering phase when it usually leaves its foodplant and may walk up to a kilometre before finding a suitable place to undertake the transformation into a pupa. During this phase it is very prone to predation. Dispersal however probably reduces overall predation of pupae by spreading them over a wider area - if they were concentrated on or around the foodplant it would be easier for birds to home in on them and wipe out the whole brood.

Life Cycle and Metamorphosis

Clockwise from Top Left Siproeta epaphus Anthocharis cardamines Heliconius pupa Speckled Wood Pararge

Pupation Larvae pupate in different ways depending on which family they belong to. A larva from the family Nymphalidae for example will spin a tiny button of silk on a leaf or stem, and anchor itself to it by its tail. The tail has an appendage called a cremaster, which is equipped with microscopic hooks to hold it securely to the silk. Larvae of Papilionidae and Pieridae do the same, but additionally spin a silken girdle around their waist. Lycaenidae and Riodinidae donâ&#x20AC;&#x2122;t possess cremasters so they either pupate on the ground, or attach themselves by a silk girdle to a leaf or stem. Hesperiidae pupate loosely, usually within a flimsy silken tent. The larvae of most moths pupate loosely in a chamber just below the surface of the ground. Others, including Saturniidae, Bombycidae and Lasiocampidae pupate inside a tough silk cocoon spun on the leaves, stems or branches of their foodplants. The pre-pupal caterpillar remains motionless for 2-3 days preparing itself for its final moult. During this time the prolegs start to shrink, the thoracic segments become enlarged, and the larva adopts a curled humpbacked position. When the final moult takes place the skin splits behind the head, but instead of a caterpillar walking out of the old skin, what emerges is quite different in nature - a legless, wriggling, non-eating entity called a pupa or chrysalis. At first the pupa is soft, limp and highly vulnerable to attack by parasitoid wasps and flies. Within a few hours however the skin hardens into a tough shell that will protect the insect until it ultimately emerges as an adult butterfly or moth.

Life Cycle and Metamorphosis

Image on Right Side Urodus cocoon

Cocoons Most Skipper larvae ( Hesperiidae ), and those of moth families including Lasiocampidae, Arctiidae, Saturniidae, Notodontidae and Zygaenidae pupate within cocoons. These range from flimsy affairs composed of little more than a few strands of silk, to hardened shells made of dozens of layers of silk interwoven with bits of chewed bark, such as that of the Puss moth Cerura vinula. Some cocoons are formed among living foliage on trees and bushes, while others including that of the American Moon moth Actias luna are formed among dead leaves on the forest floor. The cocoon of the Emperor moth Saturnia pavonia has a lobster-pot design with a special â&#x20AC;&#x153;doorâ&#x20AC;? which allows the moth to make its escape, but prevents other creatures from entering. One of the strangest and most beautiful cocoons is that of the Amazonian moth Urodus ( Urodidae ) which has a coarse open mesh design with an exit at the bottom, and hangs like a pendulum from a 20cm long silk cord. It seems likely that the cord may function to isolate the pupa from marauding ants, but little is known about the biology of this species. The cocoons of the silkworm moth Bombyx mori (Bombycidae) have been used for centuries for the production of silk. Several species in the family Saturniidae including Antheraea mylitta also produce silk of commercial quality.

Life Cycle and Metamorphosis

Diapause The pupal stage of the lifecycle can last anything from 1 to 40 weeks depending on the species. In polyvoltine species ( those which have more than one generation per year ), the summer pupal stage will be short - often just a few days; but the 2nd brood may overwinter as a pupa from August or September until the following May or June. Some species occasionally delay their emergence and remain as pupae for 2 or more winters. This is a natural safeguard because in an unusually short or harsh summer a species might be unable to breed in viable numbers. By staggering its emergence over 2 or 3 years it spreads the risk and ensures that at least a few adults will appear and reproduce each year, regardless of the weather. Metamorphosis The popular belief that the bodily fluids within the pupa break down into a â&#x20AC;&#x153;soupâ&#x20AC;? and later reform in the shape of a butterfly is largely untrue. The change from larva to adult butterfly is actually a very gradual process. Clusters of stem cells from which the wings develop are present in segments 2 and 3 of small larvae. They replicate and diversify during larval development. In the last few days prior to pupation the development accelerates, so that the wings are almost fully formed at the time of pupation. The same applies to the antennae, eyes and palpi, all of which are visible on the newly formed pupa. Within the pupa the changes that take place are surprisingly minor. The wing scales develop as plate-like extensions from cells on the wing surface. The heart, brain, eyes, antennae, proboscis etc all develop from

the fairly simple organs â&#x20AC;&#x153;hiddenâ&#x20AC;? within the larva, into the recognisable features of an adult butterfly.About 2 or 3 days before the butterfly is due to emerge it changes colour, and the colour and pattern of the wings can usually be clearly seen.

Gonepteryx rhamni with wing patterns showing through, just prior to emergence

At this stage female pupae of many species exude pheromones which attract males even before the butterfly has emerged. In Costa Rica e.g. I have observed that female pupae of Heliconius erato, when close to emergence, often have several male adults in very close attendance. A frantic battle takes place the instant the female hatches, as all the males struggle to copulate with her, not even allowing her time to expand and dry her wings. The mated pair then have to endure the continuing aggravation of the remaining males, which are often extremely persistent, trying to prise the pair apart. Eventually, with the approach of dusk, the unsuccessful males disperse, allowing the pair to remain copulated until the next morning.

Life Cycle and Metamorphosis

STAGE 4: Imago Emergence of the adult butterfly or moth from the pupa is triggered by factors including humidity, temperature, light level and time of day. Most butterflies emerge shortly after dawn. The spiracles of the butterfly within the pupa are linked by short tubes to the spiracle openings on the pupa shell. Just prior to emergence air is drawn in through these tubes, enabling the butterfly to pump up its body, which causes the shell of the pupa to split, just behind the head. The butterfly then forces its way out, using its legs to pull itself clear of the empty pupal shell. If the pupa was formed within a silken shelter, as is the case with most Hesperiidae species, the butterfly first ejects solvents from the proboscis. These soften the silk enough to allow it to push its way out. Having emerged and settled into position, the insect then spends several minutes hanging virtually motionless. During this time it pumps fluids into the wing veins, causing the wings to expand to their full size. After drying the wings, and before taking their first flight, butterflies and moths expel the metabolic waste product meconium from their abdomens, in the form of a pinkish liquid. Male butterflies usually fly off as soon as their wings are hardened, but females of many species tend to stay within a few metres of the emergence site until mated.

Life Cycle and Metamorphosis

Eueides lybia, newly emerged from chrysalis, Rio Madre de Dios, Peru

Sex ratios It is often claimed that more male butterflies emerge than females. The most quoted example is of Rajah Brookeâ&#x20AC;&#x2122;s Birdwing Trogonoptera brookiana whose males are sometimes stated to outnumber females by a ratio of as much as 10:1. These claims however are caused by sampling inadequacies - females of most species are more secretive in behaviour, better camouflaged, and tend to spend most of their lives in habitats that are less accessible to observers, e.g. in the forest canopy. Males on the other hand tend to be more colourful and are considerably more visible in their behaviour, e.g. males of brookiana and many other species habitually aggregate in large numbers to imbibe moisture from muddy ground. Captive breeding experiments with brookiana and hundreds of other species have proven that both sexes actually emerge in similar numbers. In most species males emerge at least a day or two before females. The explanation usually given for this is that females usually mate on the day they emerge, so it is advantageous if there are already plenty of males available to them. Another factor not usually mentioned in literature is that males of some species are not capable of mating until they are 2-3 days old. This is because they need to feed in order to accumulate alkaloids that are vital to reproduction. Well known examples of this include the Purple Emperor whose males feed at dung, Swordtails and Daggerwings which feed at urine, and Glasswings such as Pteronymia sao which feed on decomposing plant material. The latter derive pyrrolizidine alkaloids from the plants, which are used in the production of pheromones and defensive toxins, as well as for reproductive purposes.

Life Cycle and Metamorphosis

Feeding behaviour Males of many tropical species are regularly observed imbibing dissolved minerals from damp mud, bird droppings, aphid secretions, sap runs, or even from carrion. The minerals are later passed to the females during copulation, and may contain vital nutrients necessary for the production of fertile eggs. In temperate regions both sexes of most species feed primarily at nectar, but males of several species, e.g. Apatura iris, Lysandra coridon, Pyrgus alveus, Thymelicus lineola and Mellicta athalia commonly imbibe mineralised moisture, or visit dung. Certain members of the subfamily Heliconiinae are unusual in that their females use nectar to dissolve pollen which they collect from rainforest flowers. Studies by Gilbert of captive Heliconius ethilla in Trinidad have shown that females deprived of pollen only lay about 15% of the number of eggs laid by females that have access to pollen. The pollen provides nutrients that cannot be sequestered from other sources, and contributes greatly to the longevity of the butterflies. They have been recorded as living for up to 8 months as adults - most other tropical species live for only a few days.

Heliconius xanthocles, sequestering pollen from Psychotia â&#x20AC;&#x2DC;hotlipsâ&#x20AC;&#x2122; flowers

Life Cycle and Metamorphosis

Adonis Blue Lysandra bellargus, male, Ballard Down, Dorset

Adonis Blue Lysandra bellargus, female, Ballard Down, Dorset

The daily routine Male and female butterflies of any given species usually behave very differently. In most species the males are highly active, and their behaviour follows a predictable cycle of feeding, basking, and patrolling in search of females. Males of other species are often highly territorial, and will defend their territories against other insects including wasps, flies, and flying beetles. If another male of the same species enters their territory, they engage in an aerial sortie, spiralling high above the trees until the intruding butterfly is ousted. Female butterflies live entirely different lives. Prior to mating they are often sedentary, remaining very close to the spot where they emerged from the pupa. After mating they seek places to lay their eggs, but usually fly only short distances between bouts of egg laying. These differences in behaviour are reflected in their appearance - males need to be noticed, so are generally more colourful than females. The Adonis Blue Lysandra bellargus is a good example : the males are a brilliant iridescent blue colour, but the females are drab dark brown creatures - they spend most of their time crawling about on the ground amongst short grasses, looking for places to lay their eggs, but need to bask periodically so they can maintain their body temperatures. When basking on the ground, their drab colouration helps to camouflage them so they escape predation.

Lifespan The whole lifecycle from egg to adult can take just 3 weeks to complete in many tropical species. In temperate regions the lifecycle of the summer generation may be complete within 6 weeks, but many species only produce a single generation in a year. In sub-arctic zones some species such as Parnassius eversmanni, Boloria natazhati and Oeneis alpina take 2 years to complete the lifecycle. Clossiana selene, ( Nymphalinae : Melitaeini ) seed-head, Wiltshire, Kent

The lifespan of butterflies varies considerably from one species to another. Captive butterflies, if fed regularly can live for several weeks. Wild butterflies are subject to predation and the extremes of climate, so while some may have the potential to live longer, in practice the average lifespan is just 7 or 8 days. There are however several notable exceptions to this general rule. Some butterflies, e.g. Monarchs and Tortoiseshells, hibernate as adults, and these species often live for several months. The longest lived European species are the Brimstone and Peacock â&#x20AC;&#x201C; both emerge in early July, and often survive until the following June.

Polygonia c-album, ( Nymphalidae ) hibernating beneath a branch, West Sussex

Certain tropical species are also capable of surviving for equally long periods. In Central & South America female Heliconius butterflies sequester pollen from Psiguria, Anguria and Gurania flowers in the rainforest. The pollen collected from the flowers is processed by the females to extract amino acids which increase longevity and enable them to produce eggs for up to 9 months. Other tropical species e.g. the Satyrine Taygetis mermeria and certain Ithomiines, Heliconiines and Danaines are able to extend their lives by aestivating during the dry season, and can live for up to 11 months.

Families of Butterflies and Moths

Butterfly Families The butterflies form the clade Rhopalocera, which is composed of three main superfamilies that Hedyloidea, which is the moth butterfly family Hedylidae, the Hesperioidea, which is the skipper family Hesperiidae, and the Papilionoidea, which is the true butterfly familes Papilionidae, Pieridae, Nymphalidae, Lycaenidae and Riodinidae. These families mentioned above are all monophyletic. The Hedyloidea is the sister group to the other two superfamilies. Within the Papilionoidea, Papilionidae is the sister group to the other families and Pieridae is the sister group to Nymphalidae, Lycaenidae and Riodinidae. Hedylidae, the “American moth-butterflies”, is a family of insects in the lepidopteran order, representing the superfamily Hedyloidea. They have traditionally been viewed as an extant sister group of the butterfly superfamily Papilionoidea. In 1986, Scoble combined all species into a single genus Macrosoma, comprising 35 currently recognized and entirely Neotropical species, as a novel concept of butterflies. Hedylidae were previously treated as a tribe of Geometridae: Oenochrominae, the “Hedylicae” Prout considered they might even merit treatment as their own family. Scoble first considered them to be a hitherto unrecognised group of butterflies and also suggested Hedylidae might possibly constitute the sister group of the “true” butterflies (Papilionoidea), rather than of (Hesperioidea + Papilionoidea). Weintraub and Miller argued against this placement. In 1995, Weller and Pashley found that molecular data did indeed place Hedylidae with the butterflies and a more comprehensive study in 2005 based on 57 exemplar taxa, three

genes and 99 morphological characters, recovered the genus Macrosoma as sister to the (“true butterflies” + “skippers”). However, the most recent phylogenetic analyses shows that skippers are true butterflies belonging within the clade Papilionoidea, whereas the hedylids are a sister group that may be closely related to the obtectomeran moths. This is contrary to some earlier studies that had shown both the skippers and hedylids as being nested within the Papilionoidea.

Image of Hedylidae

Since there are no obvious gaps between supposed species groups, according to basic morphological structure, Scoble (1986) synonymised the five pre-existing genera of Hedylidae (33 of which had been described in Phellinodes) into just one genus. However, a phylogenetic analysis of all Macrosoma species is still needed.

Families of Butterflies and Moths

Skippers are a family, Hesperiidae, of the Lepidoptera (moths and butterflies). Being diurnal, they are generally called butterflies. They were previously placed in a separate superfamily, Hesperioidea; however, the most recent taxonomy places the family in the superfamily Papilionoidea. They are named for their quick, darting flight habits. Most have the antenna tip modified into a narrow hook-like projection. More than 3500 species of skippers are recognized, and they occur worldwide, but with the greatest diversity in the Neotropical regions of Central and South America. Traditionally, the Hesperiidae were placed in a monotypic superfamily Hesperioidea, because they are morphologically distinct from other Rhopalocera (butterflies), which mostly belong to the typical butterfly superfamily Papilionoidea. The third and rather small butterfly superfamily is the moth-butterflies (Hedyloidea) which are restricted to the Neotropics. However, recent phylogenetic analyses suggest the traditional Papilionoidea are paraphyletic, and thus the subfamilies should be reorganised to reflect true cladistic relationships. Collectively, these three groups of butterflies share many characteristics, especially in the egg, larval, and pupal stages.However, skippers have the antennae clubs hooked backward like a crochet hook, while the typical butterflies have club-like tips to their antennae, and moth-butterflies have feathered or pectinate (combshaped) antennae similar to moths. Skippers also have generally stockier bodies and larger compound eyes than the other two groups, with stronger wing muscles in the plump thorax, in this resembling many moths more than the other two butterfly lineages do. But unlike, for example, the Arctiidae, their wings are usually small

in proportion to their bodies. Some have larger wings, but only rarely as large in proportion to the body as in other butterflies. When at rest, skippers keep their wings usually angled upwards or spread out, and only rarely fold them up completely. Many species of skippers look frustratingly alike. For example, some species in the genera Amblyscirtes, Erynnis (duskywings) and Hesperia (branded skippers) cannot currently be distinguished in the field even by experts. The only reliable method of telling them apart involves dissection and microscopic examination of the genitalia, which have characteristic structures that prevent mating except between conspecifics. Image of Hesperiidae

Families of Butterflies and Moths

Lycaenidae is the second-largest family of butterflies (behind Nymphalidae, brush-footed butterflies), with over 6,000 species worldwide, whose members are also called gossamer-winged butterflies. They constitute about 30% of the known butterfly species. The family is traditionally divided into the subfamilies of the blues (Polyommatinae), the coppers (Lycaeninae), the hairstreaks (Theclinae) and the harvesters (Miletinae). Adults are small, under 5 cm usually, and brightly coloured, sometimes with a metallic gloss. Larvae are often flattened rather than cylindrical, with glands that may produce secretions that attract and subdue ants. Their cuticles tend to be thickened. Some larvae are capable of producing vibrations and low sounds that are transmitted through the substrates they inhabit. They use these sounds to communicate with ants. Adult individuals often have hairy antenna-like tails complete with black and white annulated (ringed) appearance. Many species also have a spot at the base of the tail and some turn around upon landing to confuse potential predators from recognizing the true head orientation. This causes predators to approach from the true head end resulting in early visual detection. Lycaenids are diverse in their food habits and apart from phytophagy, some of them are entomophagous feeding on aphids, scale insects, and ant larvae. Some lycaenids even exploit their association with ants by inducing ants to feed them by regurgitation, a process called trophallaxis. Not all lycaenid butterflies need ants, but about 75% of species associate with ants, a relationship called myrmecophily.

Image of Lycaenidae

In some species, larvae are attended and protected by ants while feeding on the host plant, and the ants receive sugar-rich honeydew from them, throughout the larval life, and in some species during the pupal stage. In other species, only the first few instars are spent on the plant, and the remainder of the larval lifespan is spent as a predator within the ant nest. It becomes a parasite, feeding on ant regurgitations, or a predator on the ant larvae. The caterpillars pupate inside the antâ&#x20AC;&#x2122;s nest and the ants continue to look after the pupa. Just before the adult emerges the wings of the butterfly inside the pupal case detach from it, and the pupa becomes silvery. The adult butterfly emerges from the pupa after three to four weeks, still inside the ant nest. The butterfly must crawl out of the ant nest before it can expand its wings.

Families of Butterflies and Moths

Nymphalidae are the largest family of butterflies with about 6,000 species distributed throughout most of the world, belonging to the superfamily Papilionoidea. These are usually medium-sized to large butterflies. Most species have a reduced pair of forelegs and many hold their colourful wings flat when resting. They are also called brush-footed butterflies or four-footed butterflies, because they are known to stand on only four legs while the other two are curled up; in some species, these forelegs have a brush-like set of hairs, which gives this family its other common name. Many species are brightly coloured and include popular species such as the emperors, monarch butterfly, admirals, tortoiseshells, and fritillaries. However, the under wings are, in contrast, often dull and in some species look remarkably like dead leaves, or are much paler, producing a cryptic effect that helps the butterflies blend into their surroundings. In the adult butterflies, the first pair of legs is small or reduced, giving the family the other names of four-footed or brush-footed butterflies. The caterpillars are hairy or spiky with projections on the head, and the chrysalids have shiny spots. The forewings have the submedial vein (vein 1) unbranched and in one subfamily forked near the base; the medial vein has three branches, veins 2, 3, and 4; veins 5 and 6 arise from the points of junction of the discocellulars; the subcostal vein and its continuation beyond the apex of cell, vein 7, has never more than four branches, veins 8â&#x20AC;&#x201C;11; 8 and 9 always arise from vein 7, 10, and 11 sometimes from vein 7 but more often free, i.e., given off by the subcostal vein before apex

of the cell. The hindwings have internal and precostal veins. The cell in both wings is closed or open, often closed in the fore, open in the hindwing. The dorsal margin of the hindwing is channelled to receive the abdomen in many of the forms. The antennae always have two grooves on the underside; the club is variable in shape. Throughout the family, the front pair of legs in the male, and with three exceptions (Libythea, Pseudergolis, and Calinaga) in the female also, is reduced in size and functionally impotent; in some, the atrophy of the forelegs is considerable. In many of the forms of these subfamilies, the forelegs are kept pressed against the underside of the thorax, and are in the male often very inconspicuous. Image of Nymphalidae

Families of Butterflies and Moths

Swallowtail butterflies are large, colorful butterflies in the family Papilionidae, and include over 550 species. Though the majority are tropical, members of the family inhabit every continent except Antarctica. The family includes the largest butterflies in the world, the birdwing butterflies of the genus Ornithoptera. Swallowtails have a number of distinctive features; for example, the papilionid caterpillar bears a repugnatorial organ called the osmeterium on its prothorax. The osmeterium normally remains hidden, but when threatened, the larva turns it outward through a transverse dorsal groove by inflating it with fluid. The forked appearance of the swallowtails’ hindwings, which can be seen when the butterfly is resting with its wings spread, gave rise to the common name swallowtail. As for its formal name, Linnaeus chose Papilio for the type genus, as papilio is Latin for “butterfly”. For the specific epithets of the genus, Linnaeus applied the names of Greek heroes to the swallowtails. The type species: Papilio machaon honored Machaon, one of the sons of Asclepius, mentioned in the Iliad. As of 2005, 552 extant species have been identified which are distributed across the tropical and temperate regions. Various species inhabit altitudes ranging from sea level to high mountains, as in the case of most species of Parnassius. The majority of swallowtail species and the greatest diversity are found in the tropics and subtropical regions between 20°N and 20°S,: particularly Southeast Asia, and between 20°N and 40°N in East Asia. Only 12 species are found in Europe and only one species, Papilio machaon is found in the British Isles. North America has 40 species, including several tropical

species and Parnassius. The northernmost swallowtail is the Siberian Apollo (Parnassius arcticus), found in the Arctic Circle in northeastern Yakutia, at altitudes of 1500 meters above sea level. In the Himalayas, various Apollo species such as Parnassius epaphus, have been found at altitudes of 6,000 meters above sea level.

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Families of Butterflies and Moths

Pieridae are a large family of butterflies with about 76 genera containing about 1,100 species, mostly from tropical Africa and tropical Asia with some varieties in the more northern regions of North America. Most pierid butterflies are white, yellow, or orange in coloration, often with black spots. The pigments that give the distinct coloring to these butterflies are derived from waste products in the body and are a characteristic of this family. The name “butterfly” is believed to have originated from a member of this family, the brimstone, Gonepteryx rhamni, which was called the “butter-coloured fly” by early British naturalists. The sexes usually differ, often in the pattern or number of the black markings. The larvae (caterpillars) of a few of these species, such as Pieris brassicae and Pieris rapae, commonly seen in gardens, feed on brassicas, and are notorious agricultural pests. Males of many species exhibit gregarious mud-puddling behavior when they may imbibe salts from moist soils. The Pieridae have the radial vein on the forewing with three or four branches and rarely with five branches. The forelegs are well developed in both sexes, unlike in the Nymphalidae, and the tarsal claws are bifid, unlike in the Papilionidae. Like the Papilionidae, the Pieridae also have their pupae held at an angle by a silk girdle, but running at the first abdominal segment, unlike the thoracic girdle seen in the Papilionidae.

Species with more than one generation usually have distinct seasonal variation in appearance. Adults of all species visit flowers for nectar, and adults of both sexes have three pairs of walking legs. Males patrol in search of receptive mates, and females lay columnar eggs on leaves, buds, and stems. The majority of caterpillars of North American whites and sulphurs feed on legumes or crucifers (members of the Mustard family). Typically, temperate species overwinter in the pupal or larval stage, while tropical species overwinter as adults.

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Families of Butterflies and Moths

Riodinidae is the family of metalmark butterflies. The common name â&#x20AC;&#x153;metalmarksâ&#x20AC;? refers to the small metallic-looking spots commonly found on their wings. There are 1532 species and 146 genera of metalmark butterflies in the world. Although mostly neotropical in distribution, the family is represented both in the Nearctic and the Palearctic. The family includes small to medium-sized species, from 12 to 60 mm wingspan, often with vibrant structural colouring. The wing shape is very different within the family. They may resemble butterflies in other groups, some are similar to Satyrinae, some are bright yellow reminiscent of Coliadinae and others (examples Barbicornis, Rhetus arcius, Helicopis, Chorinea) have tails as do Papilionidae. In almost all Riodinidae, the coxae of the front legs are extended on males jutting out over the trochanter (only hinted at in Styx infernalis and Corrachia leucoplaga). If there are similar projections in Lycaenidae (in genera Curetis, Feniseca and Poritia), they are built differently in detail and may be, for example, dorsally convex. In addition, almost all Riodinidae in contrast to the Lycaenidae have a humeral vein in the hindwings and the costa is thickened (exceptions in the subfamily Hamearinae). The head in relation to the eyes is wider than in Lycaenidae, making the antennal bases further away from the eye. The relatively long antennae often reach half of the front wing length. Riodinidae have an unusual variety in chromosome numbers, only some very basal groups have the number typical for butterflies (between 29 and 31) or the number characteristic of Lycaenidae (23 to 24). Numbers

between 9 and 110 occur. In some cases, representatives of a morphologically indistinguishable cryptospecies have different chromosome numbers and are reproductively isolated. Like the lycaenids, the males of this family have reduced forelegs while the females have full-sized, fully functional forelegs. The foreleg of males is often reduced and has a uniquely shaped first segment (the coxa) which extends beyond its joint with the second segment, rather than meeting it flush. They have a unique venation on the hindwing: the costa of the hindwing is thickened out to the humeral angle and the humeral vein is short.

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Common Buckeye Junonia coenia, the common buckeye or buckeye, is a butterfly in the family Nymphalidae. It is found in southern Manitoba, Ontario, Quebec, and Nova Scotia and all parts of the United States Scientific name: Junonia coenia Higher classification: Junonia Rank: Species

Limenitis Arthemis The white admiral or red-spotted purple is a polytypic species of North American brush-footed butterfly, common throughout much of the eastern United States. L. a. Scientific name: Limenitis arthemis Higher classification: Limenitis Rank: Species

Pearl Crescent The pearl crescent is a butterfly of North America. It is found in all parts of the United States except the west coast, and throughout Mexico and parts of southern Canada, in particular Ontario. Scientific Name: Phyciodes tharos Higher Classification: Phyciodes Rank: Species

Colias Eurytheme Colias eurytheme, the orange sulphur, also known as the alfalfa butterfly and in its larval stage as the alfalfa caterpillar, is a butterfly of the family Pieridae. Scientific name: Colias eurytheme Higher classification: Colias Rank: Species

Vanessa Cardui Vanessa cardui is a well-known colorful butterfly, known as the painted lady, or in North America as the cosmopolitan. This butterfly has a strange habit of flying in a sort of screw shape. Scientific name: Vanessa carduie Higher classification: Painted lady Rank: Species

Anthocharis Cardamines Anthocharis cardamines, the orange tip, is a butterfly in the family Pieridae. Scientific Name: Anthocharis cardamines Higher Classification: Anthocharis Rank: Species

Vanessa Atalantal Vanessa atalanta, the red admiral or red admirable, is a well-known colourful butterfly, found in temperate Europe, Asia and North America. The red admiral has a 45â&#x20AC;&#x201C;50 mm wingspan. Scientific name: Vanessa atalanta Higher classification: Painted lady Rank: Species

Small Tortoiseshell The small tortoiseshell is a colourful Eurasian butterfly in the family Nymphalidae Scientific name: Aglais urticae Higher classification: Aglais Rank: Species

Heliconius Melpomene Heliconius melpomene, the postman butterfly, common postman or simply postman, is one of the heliconiine butterflies found from Mexico to northern South America. Scientific Name: Heliconius melpomene Higher Classification: Heliconius Rank: Species

Bibliography

Sbordoni, Valerio, and Saverio Forestiero. Butterflies of the world. Willowdale, Ont.: Firefly , 1998. Print. Introducing History, Origin and Fossils of Butterflies Hall, J.P.W., Robbins, R.K. and Harvey, D.J. (2004). “Extinction and biogeography in the Caribbean: new evidence from a fossil riodinid butterfly in Dominican amber.” Proceedings of the Royal Society of London B, 271: 797–801. Meyer, Herbert William; Smith, Dena M . (2008). Paleontology of the Upper Eocene Florissant Formation, Colorado. Geological Society of America. p. 6. ISBN 978-0-8137-2435-5. “Lepidoptera – Latest Classification”. Discoveries in Natural History & Exploration. University of California. Retrieved 15 July 2011. “Hedylidae.” Wikipedia. Wikimedia Foundation, 31 July 2017. Web. 01 Aug. 2017. Information about hedylidae

Image Sources

Gardenswithwings.com. (2017). Butterfly Wings, Eyes, Antennae, Legs, and Proboscis Pictures : Gardens With Wings. [online] Available at: http://www.gardenswithwings.com/facts-info/a0812ButterflyBody.html [Accessed 18 Aug. 2017]. Gardenswithwings.com. (2017). Butterfly Wings, Eyes, Antennae, Legs, and Proboscis Pictures : Gardens With Wings. [online] Available at: http://www.gardenswithwings.com/facts-info/a0812ButterflyBody.html [Accessed 18 Aug. 2017]. Learnaboutbutterflies.com. (2017). Butterfly Anatomy - Head. [online] Available at: http://www.learnaboutbutterflies.com/Anatomy.htm [Accessed 18 Aug. 2017]. Learnaboutbutterflies.com. (2017). Butterfly Anatomy - Head. [online] Available at: http://www.learnaboutbutterflies.com/Anatomy.htm [Accessed 18 Aug. 2017]. Learnaboutbutterflies.com. (2017). Butterfly Lifecycle - chrysalis / pupa. [online] Available at: http://www. learnaboutbutterflies.com/Lifecycle%207%20-%20chrysalis.htm [Accessed 18 Aug. 2017].