Butterfly And Bombyx mori

A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured wings, and conspicuous, fluttering flightSony VAIO PCG-31114V battery. Butterflies comprise the true butterflies (superfamily Papilionoidea), the skippers (superfamily Hesperioidea) and the moth-butterflies (superfamily Hedyloidea). All the many other families within the Lepidoptera are referred to as moths. The earliest known butterfly fossils date to the mid Eocene epoch, between 40–50 million years agoSony VAIO PCG-31113V battery. Butterflies exhibit polymorphism, mimicry and aposematism. Some, like the Monarch, will migrate over long distances. Some butterflies have evolved symbiotic and parasitic relationships with social insects such as ants. Some species are pests because in their larval stages they can damage domestic crops or treesSony VAIO PCG-31112V battery; however, some species are agents of pollination of some plants, and caterpillars of a few butterflies (e.g., Harvesters) eat harmful insects. Culturally, butterflies are a popular motif in the visual and literary arts. Etymology The name is derived from Middle English buterflie, butturflye, boterflye, from Old English butorflēoge, buttorflēoge, buterflēoge, perhaps a compound of butor (beater), mutation of bēatan (to beat), and flēoge (fly). Sony VAIO PCG-31111V battery Alternate etymology connects the first element to butere (butter) as the name may have originally been applied solely to butterflies of a yellowish or butter-colour. This may have merged later with the belief that butterflies ate milk and butter (compare Middle High German molkendiep -literally “milk-thief”; Modern German Molkendieb and Low German BotterlickerSony VAIO PCG-31114M battery - literally “butter-licker”), or that they excreted a butter-like substance (compare Middle Dutch boterschijte - literally “butter-shitter”, also Middle Dutch botervliege, Dutch botervlieg, German butterfliege). Life cycle It is a popular belief that butterflies have very short life spans.[by whom?] However, butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupal or egg stages and thereby survive winters. Sony VAIO PCG-31113M battery Butterflies may have one or more broods per year. The number of generations per year varies from temperate to tropical regions with tropical regions showing a trend towards multivoltinism. Eggs Egg of Ariadne merione Butterfly eggs are protected by a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully developSony VAIO PCG-31112M battery. Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly and moth eggs vary greatly in size between species, but they are all either spherical or ovate. Butterfly eggs are fixed to a leaf with a special glue which hardens rapidly. As it hardens it contracts, deforming the shape of the eggSony VAIO PCG-31111M battery. This glue is easily seen surrounding the base of every egg forming a meniscus. The nature of the glue is unknown and is a suitable subject for research. The same glue is produced by a pupa to secure the setae of the cremaster. This glue is so hard that the silk pad, to which the setae are glued, cannot be separatedSony VAIO PCG-41111V battery. Eggs are almost invariably laid on plants. Each species of butterfly has its own hostplant range and while some species of butterfly are restricted to just one species of plant, others use a range of plant species, often including members of a common family. The egg stage lasts a few weeks in most butterflies but eggs laid close to winter, especially in temperate regions, go through a diapause (resting) stageSony VAIO PCG-41112M battery, and the hatching may take place only in spring. Other butterflies may lay their eggs in the spring and have them hatch in the summer. These butterflies are usually northern species, such as the Mourning Cloak (Camberwell Beauty) and the Large and Small Tortoiseshell butterflies. Sony VAIO PCG-41111M battery Caterpillars Caterpillars of Junonia coenia. Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time in search of food. Although most caterpillars are herbivorous, a few species such as Spalgis epius and Liphyra brassolis are entomophagous (insect eating). Some larvae, especially those of the Lycaenidae, form mutual associations with ants. They communicate with the ants using vibrations that are transmitted through the substrate as well as using chemical signals. SONY VAIO PCG-21214V batteryThe ants provide some degree of protection to these larvae and they in turn gather honeydew secretions. Caterpillars mature through a series of stages called instars. Near the end of each instar, the larva undergoes a process called apolysis, in which the cuticle, a tough outer layer made of a mixture of chitin and specialized proteins, is released from the softer epidermis beneath, and the epidermis begins to form a new cuticle beneathSONY VAIO PCG-21213V battery. At the end of each instar, the larva moults the old cuticle, and the new cuticle expands, before rapidly hardening and developing pigment. Development of butterfly wing patterns begins by the last larval instar. Butterfly caterpillars have three pairs of true legs from the thoracic segments and up to 6 pairs of prolegs arising from the abdominal segments. These prolegs have rings of tiny hooks called crochets that help them grip the substrate. SONY VAIO PCG-21212V battery Some caterpillars have the ability to inflate parts of their head to appear snake-like. Many have false eye-spots to enhance this effect. Some caterpillars have special structures called osmeteria which are everted to produce smelly chemicals. These are used in defense. Host plants often have toxic substances in them and caterpillars are able to sequester these substances and retain them into the adult stageSONY VAIO PCG-21212M battery. This makes them unpalatable to birds and other predators. Such unpalatibility is advertised using bright red, orange, black or white warning colours, a practice known as aposematism. The toxic chemicals in plants are often evolved specifically to prevent them from being eaten by insects. Insects in turn develop countermeasures or make use of these toxins for their own survivalSONY VAIO PCG-21211M battery. This "arms race" has led to the coevolution of insects and their host plants.[7] Wing development Last instar wing disk, Junonia coenia Detail of a butterfly wing Wings or wing pads are not visible on the outside of the larva, but when larvae are dissected, tiny developing wing disks can be found on the second and third thoracic segments, in place of the spiracles that are apparent on abdominal segmentsSONY VAIO PCG-51212M battery. Wing disks develop in association with a trachea that runs along the base of the wing, and are surrounded by a thin peripodial membrane, which is linked to the outer epidermis of the larva by a tiny duct. Wing disks are very small until the last larval instar, when they increase dramatically in size, are invaded by branching tracheae from the wing base that precede the formation of the wing veins, and begin to develop patterns associated with several landmarks of the wingSONY VAIO PCG-51211M battery. Near pupation, the wings are forced outside the epidermis under pressure from the hemolymph, and although they are initially quite flexible and fragile, by the time the pupa breaks free of the larval cuticle they have adhered tightly to the outer cuticle of the pupa (in obtect pupae). Within hours, the wings form a cuticle so hard and well-joined to the body that pupae can be picked up and handled without damage to the wings. SONY VAIO PCG-51112M battery Pupa Chrysalis of Gulf Fritillary When the larva is fully grown, hormones such as prothoracicotropic hormone (PTTH) are produced. At this point the larva stops feeding and begins "wandering" in the quest of a suitable pupation site, often the underside of a leaf. The larva transforms into a pupa (or chrysalis) by anchoring itself to a substrate and moulting for the last time. The chrysalis is usually incapable of movement, although some species can rapidly move the abdominal segments or produce sounds to scare potential predatorsSONY VAIO PCG-51111M battery. The pupal transformation into a butterfly through metamorphosis has held great appeal to mankind. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early onSONY VAIO PCG-51111V battery, the other three will grow to a larger size. In the pupa, the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult color pattern are marked by changes in the expression of particular transcription factors in the early pupa. SONY VAIO PCG-81211V battery Adult or imago The adult, sexually mature, stage of the insect is known as the imago. As Lepidoptera, butterflies have four wings that are covered with tiny scales (see photo). The fore and hindwings are not hooked together, permitting a more graceful flight. An adult butterfly has six legs, but in the nymphalids, the first pair is reduced. After it emerges from its pupal stageSONY VAIO PCG-81111V battery, a butterfly cannot fly until the wings are unfolded. A newly emerged butterfly needs to spend some time inflating its wings with blood and letting them dry, during which time it is extremely vulnerable to predators. Some butterflies' wings may take up to three hours to dry while others take about one hour. Most butterflies and moths will excrete excess dye after hatching. This fluid may be white, red, orange, or in rare cases, blue. SONY VAIO PCG-81212M battery External morphology Adult butterflies have four wings: a forewing and hindwing on both the left and the right side of the body. The body is divided into three segments: the head, thorax, and the abdomen. They have two antennae, two compound eyes, and a proboscis. Scales Butterflies are characterized by their scale-covered wings. The coloration of butterfly wings is created by minute scalesSony VAIO PCG-81112M battery. These scales are pigmented with melanins that give them blacks and browns, but blues, greens, reds and iridescence are usually created not by pigments but the microstructure of the scales. This structural coloration is the result of coherent scattering of light by the photonic crystal nature of the scales. The scales cling somewhat loosely to the wing and come off easily without harming the butterflySONY VAIO PCG-71111M battery. Polymorphism Main article: Polymorphism (biology) Many adult butterflies exhibit polymorphism, showing differences in appearance. These variations include geographic variants and seasonal forms. In addition many species have females in multiple forms, often with mimetic forms. Sexual dimorphism in coloration and appearance is widespread in butterfliesSONY VAIO PCG-7192V battery. In addition many species show sexual dimorphism in the patterns of ultraviolet reflectivity, while otherwise appearing identical to the unaided human eye. Most of the butterflies have a sex-determination system that is represented as ZW with females being the heterogametic sex (ZW) and males homogametic (ZZ). SONY VAIO PCG-7191V battery Genetic abnormalities such as gynandromorphy also occur from time to time. In addition many butterflies are infected by Wolbachia and infection by the bacteria can lead to the conversion of males into females[12] or the selective killing of males in the egg stage.[13] Mimicry The Heliconius butterflies from the tropics of the Western Hemisphere are the classical model for Müllerian mimicry. SONY VAIO PCG-7196M battery Batesian and Mullerian mimicry in butterflies is common. Batesian mimics imitate other species to enjoy the protection of an attribute they do not share, aposematism in this case. The Common Mormon of India has female morphs which imitate the unpalatable red-bodied swallowtails, the Common Rose and the Crimson RoseSONY VAIO PCG-7195M battery. Mullerian mimicry occurs when aposematic species evolve to resemble each other, presumably to reduce predator sampling rates, the Heliconius butterflies from the Americas being a good example. Wing markings called eyespots are present in some species; these may have an automimicry role for some species. In others, the function may be intraspecies communicationSONY VAIO PCG-7194M battery, such as mate attraction. In several cases, however, the function of butterfly eyespots is not clear, and may be an evolutionary anomaly related to the relative elasticity of the genes that encode the spots.[15][16] Seasonal polyphenism Many of the tropical butterflies have distinctive seasonal forms. This phenomenon is termed seasonal polyphenism and the seasonal forms of the butterflies are called the dry-season and wet-season formsSONY VAIO PCG-7192M battery. How the season affects the genetic expression of patterns is still a subject of research.[17] Experimental modification by ecdysone hormone treatment has demonstrated that it is possible to control the continuum of expression of variation between the wet and dry-season forms.[18] The dry-season forms are usually more cryptic and it has been suggested that the protection offered may be an adaptationSONY PCG-8113M battery. Some also show greater dark colours in the wet-season form which may have thermoregulatory advantages by increasing ability to absorb solar radiation.[19] Bicyclus anynana is a species of butterfly that exhibits a clear example of seasonal polyphenism. These butterflies, endemic to Africa, have two distinct phenotypic forms that alternate according to the seasonSONY PCG-8112M battery. The wet-season forms have large, very apparent ventral eyespots whereas the dry-season forms have very reduced, oftentimes nonexistent, ventral eyespots. Larvae that develop in hot, wet conditions develop into wet-season adults whereas those growing in the transition from the wet to the dry season, when the temperature is declining, develop into dry-season adults. SONY PCG-7134M battery This polyphenism has an adaptive role in B. anynana. In the dry-season it is disadvantageous to have conspicuous eyespots because B. anynana blend in with the brown vegetation better without eyespots. By not developing eyespots in the dry-season they can more easily camouflage themselves in the brown brush. This minimizes the risk of visually mediated predationSONY PCG-7131M battery. In the wet-season, these brown butterflies cannot as easily rely on cryptic coloration for protection because the background vegetation is green. Thus, eyespots, which may function to decrease predation, are beneficial for B. anynana to express.[21] Habits Antennal shape in the Lepidoptera from C. T. Bingham (1905) The Australian painted lady feeding on a flowering shrub Butterflies feed primarily on nectar from flowers. Some also derive nourishment from pollen,[22] tree sap, rotting fruit, dung, decaying fleshSONY PCG-7122M battery , and dissolved minerals in wet sand or dirt. Butterflies are important as pollinators for some species of plants although in general they do not carry as much pollen load as bees. They are however capable of moving pollen over greater distances.[23] Flower constancy has been observed for at least one species of butterfly. SONY PCG-7121M battery As adults, butterflies consume only liquids which are ingested by means of their proboscis. They sip water from damp patches for hydration and feed on nectar from flowers, from which they obtain sugars for energy as well as sodium and other minerals vital for reproduction. Several species of butterflies need more sodium than that provided by nectar and are attracted by sodium in saltSONY PCG-7113M battery; they sometimes land on people, attracted by the salt in human sweat. Some butterflies also visit dung, rotting fruit or carcasses to obtain minerals and nutrients. In many species, this mud-puddling behaviour is restricted to the males, and studies have suggested that the nutrients collected may be provided as a nuptial gift along with the spermatophore, during mating. SONY PCG-7112M battery Butterflies use their antennae to sense the air for wind and scents. The antennae come in various shapes and colours; the hesperids have a pointed angle or hook to the antennae, while most other families show knobbed antennae. The antennae are richly covered with sensory organs known as sensillaeSONY PCG-8Z3M battery. A butterfly's sense of taste, 200 times stronger than humans,[26] is coordinated by chemoreceptors on the tarsi, or feet, which work only on contact, and are used to determine whether an egg-laying insect's offspring will be able to feed on a leaf before eggs are laid on it.[27] Many butterflies use chemical signals, pheromones, and specialized scent scales (androconia) and other structures SONY PCG-8Z2M battery (coremata or "hair pencils" in the Danaidae) are developed in some species. Vision is well developed in butterflies and most species are sensitive to the ultraviolet spectrum. Many species show sexual dimorphism in the patterns of UV reflective patches.[28] Color vision may be widespread but has been demonstrated in only a few species.[29][30] Some butterflies have organs of hearing and some species are also known to make stridulatory and clicking sounds. SONY PCG-8Z1M battery Monarch butterflies Many butterflies, such as the Monarch butterfly, are migratory and capable of long distance flights. They migrate during the day and use the sun to orient themselves. They also perceive polarized light and use it for orientation when the sun is hidden.[32] Many species of butterfly maintain territories and actively chase other species or individuals that may stray into themSONY PCG-8Y3M battery. Some species will bask or perch on chosen perches. The flight styles of butterflies are often characteristic and some species have courtship flight displays. Basking is an activity which is more common in the cooler hours of the morning. Many species will orient themselves to gather heat from the sun. Some species have evolved dark wingbases to help in gathering more heat and this is especially evident in alpine forms. SONY PCG-8Y2M battery Flight Heteronympha merope taking off See also Insect flight Like many other members of the insect world, the lift generated by butterflies is more than what can be accounted for by steady-state, non-transitory aerodynamics. Studies using Vanessa atalanta in a windtunnel show that they use a wide variety of aerodynamic mechanisms to generate force. These include wake capture, vortices at the wing edgeSONY PCG-7Z1M battery, rotational mechanisms and Weis-Fogh 'clap-and-fling' mechanisms. The butterflies were also able to change from one mode to another rapidly.[34] Migration The Monarch butterfly migrates large distances Main article: Lepidoptera migration See also Insect migration Many butterflies migrate over long distances. Particularly famous migrations are those of the Monarch butterfly from Mexico to northern USA and southern Canada, a distance of about 4000 to 4800 km (2500–3000 miles) SONY PCG-6W2M battery . Other well known migratory species include the Painted Lady and several of the Danaine butterflies. Spectacular and large scale migrations associated with the Monsoons are seen in peninsular India.[35] Migrations have been studied in more recent times using wing tags and also using stable hydrogen isotopes. SONY PCG-5J5M battery Butterflies have been shown to navigate using time compensated sun compasses. They can see polarized light and therefore orient even in cloudy conditions. The polarized light in the region close to the ultraviolet spectrum is suggested to be particularly important.[38] It is suggested that most migratory butterflies are those that belong to semi-arid areas where breeding seasons are short. SONY PCG-5K2M battery  The life-histories of their host plants also influence the strategies of the butterflies.[40] Defense Wings of a butterfly (Leopard Lacewing Cethosia cyane) become increasingly damaged as they age, and do not repair See also Defense in insects Butterflies are threatened in their early stages by parasitoids and in all stages by predators, diseases and environmental factors. They protect themselves by a variety of means. Chemical defenses are widespread and are mostly based on chemicals of plant originSONY PCG-5K1M battery. In many cases the plants themselves evolved these toxic substances as protection against herbivores. Butterflies have evolved mechanisms to sequester these plant toxins and use them instead in their own defense.[41] These defense mechanisms are effective only if they are also well advertised and this has led to the evolution of bright colours in unpalatable butterfliesSONY PCG-5J4M battery. This signal may be mimicked by other butterflies. These mimetic forms are usually restricted to the females. Eyespots on wings of Speckled Wood, Pararge aegeria, appear to distract predators from attacking the head. The left hind wing has been badly damaged by birds, but the insect is alive and able to fly. Cryptic coloration is found in many butterflies. Some like the oakleaf butterfly are remarkable imitations of leaves. SONY PCG-5J1M battery  As caterpillars, many defend themselves by freezing and appearing like sticks or branches. Some papilionid caterpillars resemble bird dropping in their early instars. Some caterpillars have hairs and bristly structures that provide protection while others are gregarious and form dense aggregations. Some species also form associations with ants and gain their protection (See Myrmecophile) SONY PCG-5G2M battery. Behavioural defenses include perching and wing positions to avoid being conspicuous. Some female Nymphalid butterflies are known to guard their eggs from parasitoid wasps.[43] Eyespots and tails are found in many lycaenid butterflies. It is thought that their function is to divert the attention of predators from the more vital head region. An alternative theory is that these cause ambush predators such as spiders to approach from the wrong end and allow for early visual detection. Sony VAIO PCG-8131M battery A butterfly's hind wings are thought to allow them to take swift, tight turns to evade predators.[45]