Insect

**Beasties** is a cless (**Insecta**) o hexapod invertebrates within the arthropod phylum that haes a chitinous exoskeleton, a three-pairt bouk (heid, thorax an abdomen), three pairs o jyntit legs, compoond een an ae pair o antennae. Thay are the maist diverse group o beasts on the planet, includin mair nor a million descrived species an representin mair nor hauf o aw kent leevin organisms. The nummer o leevin species is thocht tae be atween sax an ten million, an potentially maks up ower 90% o the differin ainimal life forms on Yird. Beasties can be fund in nearhaund aw environs, awtho anerly a smaw nummer o species bides in the oceans, a habitat dominatit bi anither arthropod group, crustaceans.

The life cycles o beasties varies but maist o thaim hatches frae eggs. Beastie growthe is hauden in bi the inelastic exoskeleton an development involves a series o mouts. The immatur stages can differ frae the adults in structur, haibit an habitat, an can include a passive pupal stage in thae groups that unnergaes 4-stage metamorphosis (see holometabolism). Beasties that unnergaes 3-stage metamorphosis is wantin a pupal stage an adults develops throu a series o nymphal stages. The heicher level relationship o the Hexapoda is unclear. Muckle fossilised beasties haes been fund frae the Paleozoic Era, includin giant draigonflees wi weengspans o 55 tae 70&nbsp;cm (22–28&nbsp;in). The maist diverse beastie groups appears tae hae coevolved wi flouerin plants.

Adult beasties for ordinar muves aboot bi walkin, fleein or whiles soummin . As it allous for quick yet stable muvement, a wheen o beasties adopts a tripedal gait whaur thay walk wi thair legs titchin the grund in alternatin triangles. Beasties is the anely invertebrates tae hae evolved flicht. A lot o beasties spends at least pairt o thair lifes unner watter, wi larval adaptations that include sgills, an some adult beasties is aquatic an haes adaptations for soummin. Some species, siclike as watter striders, can walk on the surface o watter. Beasties is maistly solitar, but some beasties, siclike as some bees, eemocks an termites, is social an bides in muckle, weel-organised colonies. Some Beasties, siclike as earwigs, shaws maternal care, gairdin thair eggs an weans. Beasties can communicate wi ither in a wheen o weys. Male mochs can sense the pheromones o female mochs ower great distances. Ither species communicates wi soonds: cheepers stridulate, or wi rubbin thair weengs thegither, tae attract a mate an repel ither males. Lampyridae in the clock order communicates wi licht.

Humans thinks on some beasties as pests, an ettles at controllin thaim uisin insecticides an a wheen o ither techniques. Some beasties skaithes craps bi feedin on sap, leafs or fruits. A twa-three parasitic species is pathogenic. Some beasties dis complex ecological roles; blaw-flees, for ensaumple, helps consume carrion but spreids diseases and aa. Beastie pollinators is necessar tae the life cycle o a lot o flouerin plant species that maist leevin beins, includin humans, is at least pairtly dependent on; withoot thaim, the terrestrial portion o the biosphere (includin humans) wad be devastatit. A wheen ither beasties is thocht tae be ecologically benefeecial as predators an a twa-three ither anes provides direct economic benefit. Soiewirms an bees haes been uised a lot bi humans for the production o soie an hinnie, respectively. In some culturs, fowk eats the larvae or adults o parteecular beasties.

## Etymology
The wird "beastie" is a diminutive form o beast.

## Taxonomy
Tradeetional morphology-based or appearance-based systematics haes for uisual gien the Hexapoda the rank o supercless, an identifee'd fower groups within it: beasties (Ectognatha), springtails (Collembola), Protura, an Diplura, the latter three bein grouped thegither as the Entognatha on the basis o inner mooth pairts. Supraordinal relationships haes unnergane numerous chynges wi the advent o methods based on evolutionary history an genetic data.

## Morphology an pheesiology

### Freemit
Beastie bouks is sindert intae three main pairts, the heid, thorax, an abdomen. The heid is enclosed in a haurd, gey sclerotised, unsegmentit, exoskeletal heid capsule, or epicranium, that haes the feck o the sensin organs, includin the antennae, ocellus or een, an the moothpairts. The thorax is a tagma componed o three sections, the prothorax, mesothorax an the metathorax. The anterior segment, nearest tae the heid, is the prothorax, wi the major featurs bein the first pair o legs an the pronotum. The middle segment is the mesothorax, wi the major featurs bein the seicont pair o legs an the anterior weengs. The third an maist posterior segment, abuttin the abdomen, is the metathorax, that featurs the third pair o legs an the posterior wings. The abdomen is the lairgest tagma o the beastie, an that for ordinar haes 11–12 segments an isna sae strangly sclerotised as the heid or thorax. Ilka segment o the abdomen is representit bi a sclerotised tergum an sternum.

The beastie ooter skelet, the cuticle, is made up o twa layers: the epicuticle, that is a thin an wauxy watter reseestant ooter layer an haes nae chitin, an a lawer layer cried the procuticle. The procuticle is chitinous an faur thicker nor the epicuticle an haes twa layers: an ooter layer kent as the exocuticle an an inner layer kent as the endocuticle. The teuch an flexible endocuticle is biggit frae numerous layers o feebrous chitin an proteins, criss-crossin ither, while the exocuticle is rigid an haurdened.

### Internal
The nervous system o an beastie can be sindert intae a harn an a ventral nerve cord. The heid capsule is made up o sax fused segments, ilka ane wi aither a pair o ganglia, or a cluster o nerve cells ootby the harn. At least a twa-three beasties haes nociceptors, cells that detects an sends signals responsible for the sensation o pyne. Forby, beasties can learn things.

A beastie uises thair digeestive seestem tae extract nutrients an ither substances oot the meat it eats. Maist o this meat is ingeestit in the form o macromolecules an ither complex substances lik proteins, polysaccharides, fats an nucleic acids. The main structur o an beastie's digeestive seestem is a lang enclosed tube cried the alimentary canal that rins langwyse throu the bouk. The alimentary canaul airts meat unidirectionally frae the mooth tae the anus.

The reproductive seestem o female beasties haes a pair o ovaries, accessory glands, ane or mair spermathecae, an ducts connectin thir pairts. The ovaries is made up o a nummer o egg tubes, cried ovarioles that varies in size an nummer bi species. The nummer o eggs that the beastie can mak varies bi the nummer o ovarioles wi the rate that eggs can develop bein influenced bi ovariole design and aa. For males, the reproductive seestem is the testis, hingin in the bouk cavity bi tracheae an the fat bouk.

Beastie respiration is duin withoot buffs. Insteid, the beastie respiratory seestem uises a seestem o internal tubes an sacs that gases aither diffuises or is pumped throu active-like, deliverin oxygen directly tae tishies that needs it by wey o thair trachea (element 8 in nummered diagram). Syne oxygen is deleevered directly, the circulatory seestem is nae uised tae cairy oxygen, an is tharefore greatly reduced. The beastie circulatory seestem haes nae veins or arteries, an insteid haes a bittie mair nor the ae, perforatit dorsal tube that pulses peristaltically. Taewart the thorax, the dorsal tube (element 14) sinders intae chaumers an acts lik the beastie's hert. The ither end o the dorsal tube is lik the aorta o the beastie circulatin the hemolymph, arthropods' fluid analog o bluid, in the bouk cavity. Air is taen in throu openins on the sides o the abdomen cried spiracles.

## Senses an communication
A wheen beasties haes gey an sensitive an, or specialised organs o perception. Some beasties siclike as bees can perceive ultraviolet wavelenths, or detect polarised licht, while the antennae o male mochs can detect the pheromones o female mochs ower distances o mony kilometres. Some beasties displays a rudimentar sense o nummers, siclike as the solitar wasps that prays upon a single species. The mither wasp lays her eggs in individual cells an gies ilka egg a nummer o live caterpillars that the young can eat whan hatched.

A twa-three beasties, siclike as memmers o the faimilies Poduridae an Onychiuridae (Collembola), Mycetophilidae (Diptera) an the clock faimilies Lampyridae, Phengodidae, Elateridae an Staphylinidae is bioluminescent. The maist faimiliar group is the fireflees, clocks o the faimily Lampyridae. Some species can control this licht generation tae produce flashes. The function varies wi some species uisin them tae attract mates, while ither anes uises thaim tae lure prey. Maist beasties, ither nor a twa-three species o cove cheepers, can perceive licht an daurk.

Beasties wis the earliest organisms tae mak an sense soonds. Beasties maks soonds maistly bi mechanical action o appendages. In gresslowpers an cheepers, this is gotten at bi stridulation. Cicadas maks the loodest soonds amang the beasties bi makkin an amplifeein soonds wi special modifications tae thair bouk an musculature. The African cicada *[[Brevisana brevis]]* haes been meisurt at 106.7&nbsp;decibels at a distance o . Twa-three beasties, siclike as the *[[Helicoverpa zea]]* mochs, hawk mochs an Hedylid butterflees, can hear ultrasoond an tak evasive action whan thay sense that thay hae been detectit bi baukies.

## Social behaviour
Social beasties, siclike as termites, eemocks an a wheen o bees an wasps, is the maist familiar species o eusocial ainimal. Thay bide thegither in big weel-organised colonies that can be that strang integratit an genetically alike that the colonies o some species is whiles conseedert superorganisms. It is whiles argied that the various species o hinnie bee is the anely invertebrates (an indeed ane o the few non-human groups) tae hae evolved a seestem o abstract seembolic communication whaur a behaviour is uised tae *represent* an convey parteecular information aboot something in the environment.

## Locomotion
Beasties is the anely group o invertebrates tae hae developed flicht. Beastie flicht haes been a topic o great interest in aerodynamics pairtly cause o the inabeelity o steady-state theories tae expone the lift generatit bi the tottie weengs o beasties. But beastie weengs is in motion, wi flappin an vibrations, resultin in churnin an eddies, an the misconception that pheesics says "bumbees canna flee" held forrit ootthrou maist o the twintiet century. Unlik birds, a wheen smaa beasties is swept alang bi the prevailin winds awtho a lot o the bigger beasties is kent tae mak migrations.

A wheen adult beasties uises sax legs for walkin an haes adoptit a tripedal gait. The tripedal gait allous for fest walkin while ayeweys haein a stable stance an haes been studied extensively in cockroaches.

A wheen o beasties leeves aither pairt or aa o thair lifes unnerwatter. In a lot o the mair primitive orders o beastie, the immatur stages is spent in a aquatic environment. Some groups o beasties, lik certain watter clocks, haes aquatic adults as weel.

## References