1Entomology 462Orders of InsectsDavid J. Shetlar, Ph.D.The “BugDoc”The Ohio State University,OARDC & OSU ExtensionColumbus, OHRevised: September, 2007 - DJSClass Hexapoda(the insects)• Three tagmata – head, thorax, abdomen• Thorax with three pairs of legs; normally two pairs of wings in adult stage• Head with one pair of antennae• Respiration by trachea• Terrestrial & fresh water inhabitantsClass Hexapoda(all have one pair of antennae, a head, thorax & abdominal regions, three pair of legs, adults usually have wings, use trachea)Life Cycle Groups• Simple Metamorphosis (=incomplete) - egg, nymph, adult stages• Complete Metamorphosis - egg, larva, pupa, adult stagesIncomplete Metamorphosis Example(hairy chinch bug)egg 1st 2nd 3rd 4th 5th adultinstar instar instar instar instarEgg Nymphal AdultStage Stage Stage Incomplete Metamorphosis Example(hairy chinch bug)egg 1st 2nd 3rd 4th 5th normal wing short wing instar instar instar instar instar adult adultEgg Nymphal AdultStage Stage Stage Complete Metamorphosis Example(May/June beetle)egg 1st 2nd 3rd pupa adultinstar instar instarEgg Larval Pupal AdultStage Stage Stage Stage2Complete Metamorphosis Example(northern masked chafer)egg 1st 2nd 3rd pupa adultinstar instar instarEgg Larval Pupal AdultStage Stage Stage Stage Hexapod OrdersEntognathous Hexapods –Order ProturaOrder CollembolaOrder DipluraEctognathous apterygote Hexapods –Order MicrocoryphiaOrder ThysanuraPterygote Hexapods –(simple metamorphosis)Order EphemeropteraOrder OdonataOrder OrthopteraOrder PhasmatodeaOrder DermapteraOrder PlecopteraOrder Isoptera(simple metamorphosis cont’d)Order MantodeaOrder BlattodeaOrder HemipteraOrder ThysanopteraOrder PsocopteraOrder Phthiraptera(complete metamorphosis)Order ColeopteraOrder NeuropteraOrder HymenopteraOrder TrichopteraOrder LepidopteraOrder SiphonapteraOrder DipteraOrders of Insects(no metamorphosis)• Some consider these groups insect-like and place in different class or subclass.• Adults do not have wings and may molt after becoming mature• Thysanura - silverfish, firebrats• Collembola - springtailsThysanura(silverfish, firebrats; 0.4K spp.)[no wings as adults, 2-3 caudal appendages (two cerci and sometimes central telson); adults may continue to molt]Collembola(springtails; >6K spp.)[no wings as adults, caudal appendage designed for jumping (furcula & colliphore); adults may molt]Orders of Insects(simple metamorphosis)• Ephemeroptera - mayflies, shadflies• Odonata - dragonflies, damselflies• Orthoptera - grasshoppers, crickets, katydids• Dermaptera – earwigs• Plecoptera - stoneflies• Isoptera - termites3Ephemeroptera(Mayflies, shadflies, Canadian soldiers; 2K spp.)[front wings large, triangular, held over body at rest; hind wings small or absent; aquatic nymphs with abdominal gills; caudal appendages (2 or 3) long; chewing mouthparts often non-functional in adult]Odonata(dragonflies and damselflies; 5K spp.)[front and hind wings narrow with many cross veins, membranous; aquatic nymphs (naiads) predatory with caudal or rectal gills; antennae bristlelike, no abdominal cerci; chewing mouthparts]Orthoptera(grasshoppers, crickets, Katydids; >20K spp.)[front wings leathery, hind wings folded like a fan, chewing mouthparts, two cerci - usually short]Dermaptera(earwigs; 1.8K spp.)[front wings short, leathery; hind wings double folded; abdominal cerci forceps-like; chewing mouthparts]European earwig with eggsSeashore earwig adultPlecoptera(stoneflies; 2K spp.)[front wings narrow; hind wings folded fanlike; aquatic nymphs (naiads) with abdominal gills; abdominal cerci straight, moderately long; chewing mouthparts]Isoptera(termites; >2.3K spp.)[social insects, winged reproductives with both wings same size and membranous; straight or curved antennae consists of beadlike segments; abdomen broadly joined to thorax; one to two-segmented cerci; chewing mouthparts]4Orders of Insects(incomplete metamorphosis cont’d)• Mantoidea – mantids• Blattodea – cockroaches• Hemiptera - true bugs & bug-like insects• Thysanoptera - thrips• Psocoptera - barklice, booklice• Phthiraptera - biting & sucking liceMantodea(mantids, praying mantis; ~1.8K spp.)[front legs raptorial (modified for grasping), prothroaxelongated, chewing mouthparts, two short cerci][body flattened and oval, front wings leathery, hind wings folded like a fan, chewing mouthparts, two short cerci]Blattodea(cockroaches; <4K spp.)[front wings half leathery & half membranous; hind wings membranous; usually long antennae; sucking mouthparts arise from front of head]Hemiptera (s.o. Heteroptera)(true bugs; 23K spp.)Hemiptera (s.o. Auchenorrhyncha)(buglike insects: cicadas, leaf, plant & tree hoppers; 33K spp.)[front wings same texture throughout, leathery or membranous (wings often absent); long or bristlelike antennae; sucking mouthparts arise from back of head or between front legs]Hemiptera (s.o. Sternorrhyncha)(buglike insects: psyllids, whiteflies, aphids, mealybugs, & scales)5Thysanoptera(thrips; 4.5K spp.)[small; front and hind wings bladelike with hair fringe, often absent; mouthparts modified rasping sucking; antennae short]Psocoptera(psocids, booklice, barklice; >3K spp.)[front wings with reduced venation; hind wings reduced or absent; wings often absent; distinctive frontal bulge on head; long antennae; chewing mouthparts; booklice are extremely flattened][very flat, small; no wings; chewing mouthparts; external parasites of birds and mammals]Chicken biting lousePhthiraptera (Mallophaga)(biting lice; 2.7K spp.)[small, flattened; no wings; sucking mouthparts; external