The Wings A butterfly wing is made of a thin membrane webbed withveins. Colourful scales cover themembrane. They strengthen and stabilize the wings. A butterfly cannot regenerate lost scales. If a butterfly loses a lot of scales, the underlying membrane may become more prone to tears, and that could affect its ability to fly.
Scales• Scales - pigmented with melanins that give them blacks and browns.• Blues, greens, reds and iridescence are created by the microstructure of the scale.• Scales that comprised them contain photonic crystals whose atoms are spaced so precisely that only certain wavelengths of light can pass through.• The crystals are also saturated with fluorescent pigments that help them create specific wavelengths of light, visible to us as bright colours.• Tiny, mirror like structures known as distributed Bragg reflectors reflect this fluorescent light as well as all the other light the photonic crystal allows to pass through. The result: butterfly wings that transform ordinary sunlight into brilliant greens and blues incredibly efficiently.• The scales cling somewhat loosely to the wing and come off easily without harming the butterfly.
A patch of wing Scales close upA single scale Microstructure of a scale
Polymorphism• Many species have developed deceptive appearances to fool would-be predators by taking on the look of other unpalatable species.• The researchers found that at least 18 genes in a tight area on one chromosome combine to create a so-called “supergene” that functions as a single switch to control wing pattern mimicking and create as many as seven different appearances.• These butterflies are the ‘transformers’ of the insect world, but instead of being able to turn from a car into a robot with the flick of a switch, a single genetic switch allows these insects to morph into several different mimetic forms.• Evolutionary strategy - mechanism for rapidly adaptable change.
Structure • Butterflies are flying insects with two pairs of scaly wings and two segmented, clubbed antennae. • A three-part body (head, thorax and abdomen), 3 pairs of jointed legs, compound eyes, and a segmented exoskeleton.
Eggs Shape : spherical or ovateButterfly eggs are fixed to a leaf with a special glue (whose nature is unknown) which hardens rapidly. Each species of butterfly has its own host plant range.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 separated. The egg stage lasts a few weeks in most butterflies but eggs laid close to winter go through a diapause (resting) stage, and the hatching may take place only in spring.
Larvae & CaterpillarsAlmost all of them are herbivorousand some insect eating.They mature through a series ofstages called instars.At the end of each instar, the larvamoults the old cuticle, and the newcuticle expands, before rapidlyhardening and developing pigment.Development of butterfly wingpatterns begins by the last larvalinstar.Anatomy: three pairs of true legsfrom the thoracic segments and up to6 pairs of prolegs arising from theabdominal segments. These prolegshave rings of tiny hooks calledcrochets that help them grip thesubstrate.
Dangerous defenses Some caterpillars have hairs and bristlystructures that provide protection while others are gregarious and form dense aggregations. Some species also form associations with ants and gain their protection.
Pupa• The larva transforms into a pupa (or chrysalis) by anchoring itself to a substrate and moulting for the last time.• They make chrysalis make by secreting silk from 2 glands that are located inside of them. This thread will stick together and grow hard when fresh air touches them. Is often camouflaged so that predators cannot see them.• Pupal transformation into a butterfly through metamorphosis inside the cocoon : pupal wings undergo rapid mitosis and absorb a great deal of nutrients. 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.
The pupa may be covered in silk and attached to many different types of debris or may not be covered at all.The pupa stays attached to the leaf by silk spun by the caterpillar before it spins the silk for the full pupa.
Wing development• Tiny developing wing disks can be found when larvae are dissected• Increase dramatically in size during the last larval instar and begin to develop patterns associated with several landmarks of the wing.• Near pupation, the wings are forced outside the epidermis under pressure. 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.• 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. Last instar wing disk
Prepare for take-off After it emerges from its pupal stage, a butterfly cannot fly until the wings are unfolded. A newlyemerged butterfly needs to spend some time inflating its wings with blood and letting them dry, during which time it is extremely vulnerable to predators. Drying takes one to three hours.
Adult or Imago The adult, sexually mature, stage of the insect. The fore and hind wings are not hooked together. They have six legs.
Flight• Flight is driven primarily by action of the forewings.• Hind wings are thought to allow them to take swift, tight turns to evade predators.• In hotter climates butterflies can easily overheat, so they are usually active only during the cooler parts of the day, early morning, late afternoon or early evening. s to direct sunlight, which rapidly warms their flight muscles.• They rely on a variety of techniques, often employed in successive strokes, over the course of a flight.• These creatures use a number of "unconventional aerodynamic mechanisms” to generate force.• The butterflies appear to switch effortlessly among these mechanisms from stroke to stroke.
In preparation for flight, these cold blooded aerial acrobats expose their wings to direct sunlight, which rapidly warms their flight muscles.
Killer colours Host plants often have toxic substances in them and caterpillarsare able to sequester these substances and retain them into the adult stage.This helps making them unpalatable to birds and other predators. Such unpalatibility is advertised using bright red, orange, black or white warning colours. This signal may be mimicked by other butterflies(coevolution of insects and their host plants – evolutionary arms race).
Blending Options… Camouflage is also important defence strategies, which involves the use of coloration shape to blend into the surrounding environment.
DeceptionWing markings called eyespots arepresent in some species.It may have an auto-mimicry role –causing ambush predators such asspiders to approach from the wrongend and allow for early visualdetection.In others, the function may be intra-species communication, such asmate attraction.Or may be an evolutionary anomaly.
Just another leaf… 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.
A sweet foot A butterflys sense of taste, 200 times stronger than humans is coordinated by chemoreceptors on feet, which work only on contact, and are used to determine whether an egg-laying insects offspring will be able to feed on a leaf before eggs are laid on it.
Small WondersThe exact size, length and weightof a butterfly generally keepsdiffering, but the average size of abutterfly is anywhere between 0.5to 1 inches, their length is usuallybetween 8 to 12 inches and weightapproximately 0.0001 ounce.