Caterpillars are the larval form of a member of the order Lepidoptera (the insect order comprising butterflies and moths). A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Lepidoptera is an order of Insect that includes Moths and butterflies. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described A butterfly is an Insect of the order Lepidoptera. Like all Lepidoptera butterflies are notable for their unusual life cycle with a A moth is an Insect closely related to the Butterfly, both being of the order Lepidoptera. They are mostly phytophagous in food habit, with some species being entomophagous. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Entomophagy (from Greek ἔντομος éntomos, "insect(ed" and φᾰγεῖν phăgein, "to eat" which together Caterpillars are voracious feeders and many of them are considered pests in agriculture. A pest is an organism which has characteristics that are regarded by Humans as injurious or unwanted Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Many moth species are better known in their caterpillar stages because of the damage they cause to fruits and other agricultural produce. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank.

The etymological origins of the word are from the late 1400s, from Middle English catirpel, catirpeller, probably an alteration of Old North French catepelose : cate, cat (from Latin cattus) + pelose, hairy (from Latin pilōsus). Middle English is the name given by Historical linguistics to the diverse forms of the English language spoken between the Norman invasion of Old French was the Romance Dialect continuum spoken in territories which span roughly the northern half of modern France and parts of modern Belgium ^[1]

Contents 1 Anatomy 1.1 Senses 2 Classification 3 Defenses 3.1 Appearance 4 Behavior 5 Economic effects 6 Health Effects 7 References 8 See also 9 External links 10 Image Gallery

Anatomy

Most caterpillars have tubular, segmented bodies. They have three pairs of true legs on the three thoracic segments, up to four pairs of prolegs on the middle segments of the abdomen, and often a single pair of prolegs on the last abdominal segment. Prolegs are the fleshy stubby little structures found on the ventral surface of the Abdomen of most larval forms of Insects of the Order Lepidoptera In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. There are ten abdominal segments. The families of lepidoptera differ in the numbers and positioning of the prolegs.

Caterpillars grow through a series of moults; each intermediate stage is called an instar. The geometer moths or Geometridae are a family of the order Lepidoptera. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) An instar is a developmental stage of Arthropods, such as Insects, between each moult ( ecdysis) until sexual maturity is reached

Like all insects, caterpillars breathe through a series of small openings along the sides of their thorax and abdomen called spiracles. Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and These branch into the body cavity into a network of tracheae. A few caterpillars of the family Pyralidae are aquatic and have gills that let them breathe underwater. The Pyralidae or snout Moths are a family of Lepidoptera. In many ^[2]

Caterpillars have 4,000 muscles (compare humans, with 629). They move through contraction of the muscles in the rear segments pushing the blood forward into the front segments elongating the torso. The average caterpillar has 248 muscles in the head segment alone.

Senses

Caterpillars have good vision. They have a series of six tiny eyelets or 'stemmata' on each side of the lower portion of their head. For information regarding Stemma in textual analysis see Stemmatics For "stoma" or "stomata" gas exchange pores on plant leaves see These can probably form well focused, but poorly resolved images. ^[3] They move their heads from side to side probably as a means of judging distance of objects, particularly plants. They rely on their short antennae to help them locate food. Antennae (singular antenna) are paired Appendages connected to the front-most segments of Arthropods In Crustaceans they are

Some caterpillars are able to detect vibrations, usually at a specific frequency. Caterpillars of the common hook-tip moth, Drepana arcuata (Drepanoidea) produce sounds to defend their silk nests from members of their own species,^[4] by scraping against the leaf in a ritualized acoustic duel. This article is about the Moth family. For the sicklefishes see Drepaneidae; for the Drepanidinae (or Drepanididae see Hawaiian honeycreeper They detect the vibrations conducted by the plant and not air-borne sounds. Similarly, cherry leaf rollers Caloptilia serotinella defend their rolls. ^[5] Tent caterpillars can also detect vibrations at the frequency of wing beats of one of their natural enemies. ^[6]

Classification

The geometrids, also known as inchworms or loopers, are so named because of the way they move, appearing to measure the earth (the word geometrid means earth-measurer in Greek); the primary reason for this unusual locomotion is the elimination of nearly all the prolegs except the clasper on the terminal segment. The geometer moths or Geometridae are a family of the order Lepidoptera. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly

Caterpillars have soft bodies that can grow rapidly, like balloons, between moults. Only the head capsule is hardened. In caterpillars, the mandibles are tough and sharp for chewing leaves; in most adult Lepidoptera, the mandibles are highly reduced, or soft. The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place Behind the mandibles of the caterpillar are the spinnerets, for manipulating silk. A spinneret is a spider's silk -spinning organ. It is usually on the underside of a spider's Abdomen, to the rear

Some larvae of the Hymenoptera (ants, bees and wasps) order can appear like the caterpillars of the lepidoptera. Hymenoptera is one of the larger orders of Insects comprising the sawflies, Wasps Bees and Ants The name refers to These are mainly seen in the Sawfly family and while the larvae superficially resemble caterpillars, they can be distinguished by the presence of prolegs on every abdominal segment. Symphyta redirects here For the Moth Genus, see Symphyta (genus. Another difference is that lepidopteran caterpillars have crochets or hooks on the prolegs while these are absent on the sawfly larvae. Also in lepidopteran caterpillars is the upside down Y shaped suture on the front of the head. ^[3] The larvae of sawflies differ also in having prominent ocelli on the head capsule. An ocellus (plural ocelli) is a type of Photoreceptor organ in animals

Defenses

Many animals feed on caterpillars as they are protein rich, and caterpillars have evolved various defenses.

Appearance

Many caterpillars are cryptically coloured and resemble the plants on which they feed and may even have parts that mimic plant parts such as thorns. In Ecology, crypsis is the ability of an organism to avoid observation Biological mimicry occurs when a group of organisms the mimics, have Some look like objects in the environment such as bird droppings. Many feed enclosed inside silk galleries, rolled leaves or by mining between the leaf surfaces. Leaf miner is a term used to describe the Larvae of many different species of Insect which live in and eat the Leaf tissue of plants Caterpillars of Nemoria arizonaria that grow in spring feed on oak catkins and appear green. The summer brood however appear like oak twigs. The differential development is linked to the tannin content in the diet. ^[7]

More aggressive self-defense measures are taken by hairy caterpillars. These caterpillars have spiny bristles or long fine hair-like setae with detachable tips that will irritate by lodging in the skin or mucous membranes. Seta (plural setae) is a biological term derived from the Latin word for " Bristle " ^[3] However, some birds, like cuckoos, will swallow even the hairiest of caterpillars. The cuckoos are a family Cuculidae, of Near passerine Birds The order Cuculiformes, in addition to the cuckoos also includes the The most aggressive defenses are bristles associated with venom glands, called urticating hairs; a venom among the most potent defensive chemicals in any animals is produced by the South American silk moth genus Lonomia. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. The term urtication can have various meanings In Biology, it refers to the stinging hairs of Plants or Invertebrates of which South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a The Saturniidae, collectively known as saturniids, are among the largest and mostspectacular of the Lepidoptera, with an estimated 1300 to 1500 different described The genus Lonomia is a moderate-sized group of fairly cryptic saturniid moths from South America, famous not for the adults but for their amazingly It is an anticoagulant powerful enough to cause a human to hemorrhage to death (See Lonomiasis). An anticoagulant is a substance that prevents coagulation; that is it stops Blood from clotting Bleeding, technically known as hemorrhaging / haemorrhaging (see American and British spelling differences) is the loss of Blood from The genus Lonomia is a moderate-sized group of fairly cryptic saturniid moths from South America, famous not for the adults but for their amazingly ^[8] This chemical is being investigated for potential medical applications. Most urticating hairs however range in effect from mild irritation to dermatitis. Dermatitis is a Blanket term meaning any " Inflammation of the skin" (e

Plants have evolved poisons to protect themselves from herbivores and some caterpillars have evolved countermeasures and eat the leaves of these toxic plants. The Giant Swallowtail Butterfly ( Papilio cresphontes) is a Swallowtail butterfly common in various parts of North America particularly the south and east The osmeterium is a fleshy organ found in the prothoracic segment of Larvae (caterpillars of Swallowtail butterflies including Birdwings. In addition to being unaffected by the poison, they sequester it in their body, making them highly toxic to predators. The term sequestration can have different meanings according to the context These chemicals are also carried on into the adult stages. These toxic species, such as the Cinnabar moth (Tyria jacobaeae) and monarch (Danaus plexippus) caterpillars, usually advertise themselves with brightly striped or coloured in black, red and yellow—the danger colours (see aposematism). The Cinnabar moth ( Tyria jacobaeae) is a brightly coloured arctiid moth found in Europe and western and central Asia The monarch ( Danaus plexippus) is a Milkweed butterfly ( Subfamily Danainae in the family Nymphalidae. Any predator that attempts to eat a caterpillar with an aggressive defence mechanism will learn and avoid future attempts.

Some caterpillars regurgitate acidic digestive juices at attacking enemies. Many papilionid larvae produce bad smells from extrudable glands called osmeteria. Swallowtail butterflies are large colorful Butterflies which form the family Papilionidae. The osmeterium is a fleshy organ found in the prothoracic segment of Larvae (caterpillars of Swallowtail butterflies including Birdwings.

Caterpillars can evade predators by using a silk line and dropping off from branches when disturbed.

Some caterpillars obtain protection by associating themselves with ants. Ants are social Insects of the family Formicidae and along with the related families of Wasps and Bees belong to the order The Lycaenid butterflies are particularly well known for this. The Lycaenidae are the second-largest family of butterflies, with about 6000 species worldwide whose members are also called gossamer-winged butterflies They communicate with their ant protectors by vibrations as well as chemical means ^[9] and typically provide food rewards.

Some caterpillars are gregarious; large aggregations are believed to help in reducing the levels of parasitization and predation. Friendship is a term used to denote co-operative and supportive behavior between two or more beings ^[10] Clusters amplify the signal of aposematic coloration, and individuals may participate in group regurgitation or displays.

Behavior

Caterpillars have been called "eating machines", and eat leaves voraciously. The Pasture Day Moth, Apina callisto (synonym Amazelo callisto) is a species in the Noctuidae family of Moths which is as its name Most species shed their skin four or five times as their bodies grow, and they eventually pupate into an adult form. The skin is the outer covering of living tissue of an animal (or plant A pupa ( Latin pupa for doll pl pupae or pupas) is the life stage of some Insects undergoing transformation Caterpillars grow very quickly; for instance, a tobacco hornworm will increase its weight ten-thousand-fold in less than twenty days. Manduca sexta L is a moth of the family Sphingidae present through much of the American continent An adaptation that enables them to eat so much is a mechanism in a specialized midgut that quickly transports ions to the lumen (midgut cavity), to keep the potassium level higher in the midgut cavity than in the blood. ^[11]

Most caterpillars are solely herbivorous. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Many are restricted to one species of plant, while others are polyphagous. A few, including the clothes moth, feed on detritus. Tineidae is a family of Moths in the order Lepidoptera. The family contains approximately 3000 species In Biology, detritus is non-living particulate organic material (as opposed to dissolved organic material Most predatory caterpillars feed on eggs of other insects, aphids, scale insects, or ant larvae. Some are cannibals, and others prey on caterpillars of other species (e. g. Hawai'ian Eupithecia ). Eupithecia is a large Genus of Moths of the family Geometridae. A few are parasitic on cicadas or leaf hoppers. ^[12] Some Hawai'ian caterpillars (Hyposmocoma molluscivora) use silk traps to capture snails. Hyposmocoma molluscivora is a Hawaiian Moth whose Larvae are Predators capturing Snails in their Silk, much ^[13]

Many caterpillars are nocturnal. For example, the "cutworms" (of the Noctuidae family) hide at the base of plants during the day and only feed at night. The Noctuidae or Owlet moths are a family of robustly-built Moths that includes more than 35000 known species out of possibly 100000 total in more than 4200 genera Others, such as gypsy moth (Lymantria dispar) larvae, change their activity patterns depending on density and larval stage, with more diurnal feeding in early instars and high densities. The gypsy moth, Lymantria dispar, is a moth in the family Lymantriidae of Eurasian origin

Economic effects

Caterpillar cause much damage, mainly by eating leaves. The cotton bollworm causes enormous losses. Other species eat food crops. Caterpillars have been the target of pest control through the use of pesticides, biological control and agronomic practices. Pest control refers to the regulation or management of a Species defined as a pest, usually because it is perceived to be detrimental to a person's Health A pesticide is a substance or mixture of substances used to kill a pest. Biological control of pests in Agriculture is a method of controlling pests (including Insects Mites Weeds and plant diseases Agronomy is the science and technology of using plants for food fuel feed and fiber Many species have become resistant to pesticides. A pesticide is a substance or mixture of substances used to kill a pest. Bacterial toxins such as those from Bacillus thuringiensis which are evolved to affect the gut of Lepidoptera have been used in sprays of bacterial spores, toxin extracts and also by incorporating genes to produce them within the host plants. Bacillus thuringiensis is a Gram-positive, soil dwelling Bacterium of the Genus Bacillus. These approaches are defeated over time by the evolution of resistance mechanisms in the insects.

Plants evolve mechanisms of resistance to being eaten by caterpillars, including the evolution of chemical toxins and physical barriers such as hairs. Incorporating host plant resistance (HPR) through plant breeding is another approach used in reducing the impact of caterpillars on crop plants. Plant defense against herbivory or host-plant resistance (HPR includes a range of Adaptations evolved

Some caterpillars are beneficial. The silk industry is based on the silkworm caterpillar. Silk is a natural Protein Fiber, some forms of which can be woven into Textiles The best-known type of silk is obtained from cocoons

Health Effects

Caterpillar hair has been known to cause certain health effects. All species have small hairs that can irritate the skin, both through direct contact and from airborne hairs. Often, caterpillars produce venoms that are stored in these hairs as a defense against predators. Caterpillar species from approximately 12 families of moths or butterflies worldwide can inflict serious human injuries ranging from urticarial dermatitis and atopic asthma to osteochondritis, consumption coagulopathy, renal failure, and intracerebral hemorrhage. (Diaz 2005) Skin rashes are the most common, but there have been fatalities.

Caterpillar hairs have also been known to cause kerato-conjunctivitis. The sharp barbs on the end of Caterpillar hairs can get lodged in soft tissues and mucus membranes such as the eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane. (Patel et. al. 1973)

This becomes a particular problem in an indoor setting. The hairs easily enter buildings through ventilation systems and accumulate in indoor environments because their small size, which makes it difficult for them to be vented out. This accumulation increases the risk of human contact in indoor environments. (Balite et. al. 2001)

References

14. Diaz, James H. (2005). "The Evolving Global Epidemiology, Sydromic Classification, Management, and Prevention of Caterpillar Envenoming".

15. Patel RJ, Shanbhag RM. Ophthalmia nodosa - (a case report). Indian J Ophthalmol 1973;21:208

16. Corrine R Balit, Helen C Ptolemy, Merilyn J Geary, Richard C Russell and Geoffrey K Isbister, (2001)“Outbreak of caterpillar dermatitis caused by airborne hairs of the mistletoe browntail moth (Euproctis edwardsi)”

See also

• Pests and diseases of roses
• Edible caterpillars
• Larval food plants of Lepidoptera

External links

• Larva Locomotion: A Closer Look — video clips showing how monarch larvae walk
• More video clips from nature
• 3D animation Papilio polyxenes larvae walking

Image Gallery

Caterpillar of the Spurge Hawk-moth, seen in Kriegtal near Binn, Valais, Switzerland at approx. Roses ( Rosa sp) are susceptible to a number of Pests diseases and disorders Gonimbrasia belina is a species of Moth found in much of southern Africa whose large edible Caterpillar, the mopani or mopane worm Inachis io caterpillarjpg|thumb|right| Inachis io on Urtica sp 2000m altitude.	Caterpillar of the Emperor Gum Moth. The emperor gum moth, Opodiphthera eucalypti, is a species of Moth native to Australia, and can be easily found in all the states except for Tasmania	Crochets on a caterpillar's prolegs.	Actias selene with some of the spiracles identified. The Indian Moon Moth or Indian Luna Moth ( Actias selene) is a species of moth Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and
A poplar hawk-moth caterpillar (a common species of caterpillar in the UK). The Poplar Hawk-moth ( Laothoe populi) is a Moth of the family Sphingidae.	Close-up of a caterpillar face.	Ant tending a lycaenid caterpillar. The Lycaenidae are the second-largest family of butterflies, with about 6000 species worldwide whose members are also called gossamer-winged butterflies	Caterpillar of Great Orange Tip resembling the Common green vine snake Ahaetulla nasuta. Great Orange Tip, Hebomoia glaucippe is a Butterfly of the Family Pieridae that is the Yellows and Whites which is found in Asia and Australasia The Green vine snake ( Ahaetulla nasuta) is a slender green tree Snake found in India, Sri Lanka, Bangladesh, Myanmar
Life cycle of the red-humped caterpillar (Schizura concinna).	A caterpillar belonging to a family of Sphingidae or hawk-moth	Close-up photo of a Hawk-moth caterpillar	Forest tent caterpillar (Malacosoma disstria)
Caterpillars hatching on an apple tree in Victoria, BC, Canada

For a complete species list of this family see the Sphingidae species list.

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