Metamorphosis of a Caterpillar

Entomology (from Greek , entomos, "that which is cut in pieces or engraved/segmented", hence "insect"; and , Category: wiktionary - :-logia|-logia) is the scientific study of insects, a branch of arthropodology. At some 1.3 million described species, insects account for more than two-thirds of all known organisms, date back some 400 million years, and have many kinds of interactions with humans and other forms of life on earth. It is a specialty within the field of biology. Though technically incorrect, the definition is sometimes widened to include the study of terrestrial animals in other arthropod groups or other phyla, such as arachnids, myriapods, earthworms, and

slugs.

Like several of the other fields that are categorized within zoology, entomology is a taxon-based category; any form of scientific study in which there is a focus on insect related inquiries is, by definition, entomology. Entomology therefore includes a cross-section of topics as diverse as molecular genetics, behavior, biomechanics, biochemistry, systematics, physiology, developmental biology, ecology, morphology, paleontology, anthropology, robotics, agriculture, nutrition, forensic science and more.

Category: File - :Places to Go by SillyPuttyEnemies.jpg|Larva of Pyrrharctia isabella, commonly known as the Banded Woolly Bear caterpillar|right|thumb

Category: File - :Western tent caterpillars Malacosoma californicum edit1.jpg|Western tent caterpillars|right|thumb

Caterpillars are the larval form of a member of the order Lepidoptera (the insect order comprising butterflies and moths). They are mostly phytophagous in food habit, with some species being entomophagous. Caterpillars are voracious feeders and many of them are considered pests in agriculture. Many moth species are better known in their caterpillar stages because of the damage they cause to fruits and other agricultural produce.

The etymological origins of the word are from the early 1500s, from Middle English catirpel, catirpeller, probably an alteration of Old North French catepelose: cate, cat (from Latin cattus) + pelose, hairy (from Latin pil?sus)."caterpillar". Dictionary.com. The American Heritage Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. http://dictionary.reference.com/browse/caterpillar (accessed: March 26, 2008).

A pupa (Latin pupa for doll, pl: pupae or pupas) is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago. (For a list of such insects see Holometabolism).

The pupae of different groups of insects have different names such as chrysalis in the Lepidoptera and tumbler in mosquitoes. Pupae may further be enclosed in other structures such as cocoons, nests or shells.Borror, D. J. Dwight M. DeLong and Charles A. Triplehorn. An introduction to the study of insects. New York: Holt, Rinehart & Winston. Sixth Edition.

A butterfly is an insect of the order Lepidoptera. Like all holometabolous insects, butterflies' life cycle consists of four parts, egg, larva, pupa and adult. Most species are diurnal. The diverse patterns formed by their brightly coloured wings and their erratic flight have made butterfly watching a hobby.

Butterflies comprise the true butterflies (superfamily Papilionoidea), the skippers (superfamily Hesperioidea) and the moth-butterflies (superfamily Hedyloidea). Butterflies exhibit polymorphism, mimicry and aposematism. Some migrate over long distances. Some butterflies have evolved symbiotic and parasitic relationships with social insects such as ants. Butterflies are important economically as agents of pollination. In addition, a few species are pests, because they can damage domestic crops or trees in their larval stage.

Culturally, butterflies are a popular motif in the visual and literary arts.

A pheromone (from Greek ???? phero "to bear" + hormone from Greek ???? - "impetus") is a chemical signal that triggers a natural response in another member of the same species. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Their use among insects has been particularly well documented. In addition, some vertebrates and plants communicate by using pheromones.

The Monarch (Danaus plexippus) is a milkweed butterfly (subfamily Danainae), in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer.http://www.amonline.net.au/factsheets/monarch.htmhttp://calamvalecreek.awardspace.com/regal.html In Europe it is resident in the Canary Islands, the Azores, and Madeira, and is found as an occasional migrant in Western Europe. Its wings feature an easily recognizable orange and black pattern, with a wingspan of . (The Viceroy butterfly has a similar size, color, and pattern, but can be distinguished by an extra black stripe across the hind wing.) Female Monarchs have darker veins on their wings, and the males have a spot called the "androconium" in the center of each hind wing from which pheromones are released. Males are also slightly larger.

The Monarch is famous for its southward migration and northward return in summer in the Americas which spans the life of three to four generations of the butterfly.