Entomology 101 Orders of Insects David J. Shetlar, Ph.D. The “BugDoc” The Ohio State University, OARDC & OSU Extension Columbus, OH © Sept, 2009, D.J. Shetlar, all rights reserved

Class Hexapoda Three tagmata – head, thorax, abdomen (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 inhabitants

Class Hexapoda Life Cycle Groups (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 stages

Incomplete Metamorphosis Example (hairy chinch bug) egg 1st 2nd 3rd 4th 5th adult instar instar instar instar instar Egg Nymphal Adult Stage Stage Stage

Incomplete Metamorphosis Example (hairy chinch bug) egg 1st 2nd 3rd 4th 5th normal wing short wing instar instar instar instar instar adult adult Egg Nymphal Adult Stage Stage Stage

Complete Metamorphosis Example (May/June beetle) egg 1st 2nd 3rd pupa adult instar instar instar Egg Larval Pupal Adult Stage Stage Stage Stage

Complete Metamorphosis Example (northern masked chafer) egg 1st 2nd 3rd pupa adult instar instar instar Egg Larval Pupal Adult Stage Stage Stage Stage

Hexapod Orders Entognathous Hexapods – (simple metamorphosis cont’d) Order Protura Order Collembola Order Diplura Ectognathous apterygote Hexapods – Order Microcoryphia Order Thysanura Pterygote Hexapods – (simple metamorphosis) Order Ephemeroptera Order Odonata Order Orthoptera Order Phasmatodea Order Dermaptera Order Plecoptera Order Isoptera (simple metamorphosis cont’d) Order Mantodea Order Blattodea Order Hemiptera Order Thysanoptera Order Psocoptera Order Phthiraptera (complete metamorphosis) Order Coleoptera Order Neuroptera Order Hymenoptera Order Trichoptera Order Lepidoptera Order Siphonaptera Order Diptera

Orders 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 - springtails

Order Thysanura (=bristle tail) silverfish & firebrats Look like they have 3 tails – 2 cerci 1 median filament Wingless (originally) Most are covered with scales Chewing mouthparts Gradual (no) metamorphosis Feed on organic matter & starches

Thysanura (=bristletail) (silverfish, firebrats; 0.4K spp.) [no wings as adults, usually 3 caudal appendages (two cerci and median filament); adults may continue to molt] Silverfish Fourlined silverfish

Order Collembola (=glue wedge) springtails Wingless (primitively) Chewing mouthparts Gradual (no) metamorphosis Adults continue to molt Feed on plants, bacteria, & fungi Important as decomposers and bioindicators

Order Collembola (=glue wedge) springtails Tiny, most < 3 mm Collophore Water regulatory structure Underside 1st abdominal segment Furcula Forked jumping appendage Underside 4th abdominal segment Held bent under body Escape by catapulting

Collembola (=glue wedge) (springtails; >6K spp.) [no wings as adults, caudal appendage designed for jumping (furcula & colliphore); adults may molt] Springtail with furcula exposed. Globular springtail, upper and lower views, spots on head are not eyes! Eyes are lower on head.

Aquatic springtails have waxy hairs that allow them to float on the water surface. These springtails feed on algae. Springtails often have long hairs and multicolored scales.

(simple metamorphosis) Orders of Insects (simple metamorphosis) Ephemeroptera - mayflies, shadflies Odonata - dragonflies, damselflies Orthoptera - grasshoppers, crickets, katydids Dermaptera – earwigs Plecoptera - stoneflies Isoptera - termites

Order Ephemeroptera (=short lived, on the wing) Mayflies Nymphs (naiads) aquatic Wings triangular, held over back Front wings large, usually with many veins Hind wings small or absent Adults with 2 or 3 long caudal filaments Last instar nymph flies from water (subimago) Adults live for hours to a few days.

Ephemeroptera (=short lived on the wing) (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] Mayfly adults, one two-tailed and one three-tailed. Mayfly naiad.

Hexagenia, large Mayfly, subimago (last instar nymph) Hexagenia, large Mayfly, subimago (last instar nymph). Note cloudy wings and short tails. Hexagenia adult. Note clear wings and long tails.

Order Odonata (=toothed – large mandibles) Dragonflies and Damselflies Front & Hind Wings narrow Many veins and cross veins Dragonflies hold wings out at rest Damselflies hold wings over back Nymphs (naiads) aquatic Naiads predatory, have grasping mouthparts Dragonfly naiads have rectal gills Damselflies have leaflike gills on abdomen tip. Adults are beneficial predators.

(dragonflies and damselflies; 5K spp.) Odonata (=toothed) (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]

Damselfly details

Order Orthoptera (=straight wing) grasshoppers & crickets Two pairs wings Forewings leathery & narrow; protect Hindwings membranous, fan-folded Some are wingless (cave crickets) Most have hind legs enlarged for jumping Females have prominent ovipositor Produce songs by rubbing wing bases together or rubbing the wings on their legs

Order Orthoptera (straight wing) grasshoppers & crickets Chewing mouthparts Gradual metamorphosis Antennae short or long Most feed on plants Some feed on organic matter, stored products; few predatory

Orthoptera (=straight wing) (grasshoppers, crickets, Katydids; >20K spp.) [front wings leathery, hind wings folded like a fan, chewing mouthparts, two cerci - usually short]

Mating pair of grasshoppers

Female cone-nose grasshopper

Black field cricket

Order Dermaptera (=skin wing) earwigs Chewing mouthparts Gradual metamorphosis Omnivorous Mostly scavengers Occasional pests of plants Nuisance pest in homes

Order Dermaptera (=skin wing) earwigs Cerci shaped like forceps, pinchers Defense, prey capture, mating Elongate, flattened Two pairs of wings Forewings usually short, hard Hindwings membranous, folded Few species are wingless

Dermaptera (=skin wing) (earwigs; 1.8K spp.) [front wings short, leathery; hind wings double folded; abdominal cerci forceps-like; chewing mouthparts] Seashore earwig adult European earwig with eggs

Order Plecoptera (=folded wing) Stoneflies Nymphs Aquatic (naiads) Abdominal &/or thoracic gills Predators & herbivores Flat with obvious cerci Chewing Mouthparts Adults with Front wing narrow, bladelike Hind wing broad, flolded Medium to long cerci Good indicators of water quality

Plecoptera (=folded wing) (stoneflies; 2K spp.) [front wings narrow; hind wings folded fanlike; aquatic nymphs (naiads) with abdominal gills; abdominal cerci straight, moderately long; chewing mouthparts]

Giant Stonefly Adult

Order Isoptera (equal wing) termites Social Reproductives (queens & kings) Four wings of equal size Wings twice the length of the body Wings lack cross-veins Workers & soldiers Lack wings Body white Distinguish from ants: Lack of elbowed antennae No constriction between abdomen & thorax

Order Isoptera (=equal wing) termites Chewing mouthparts Gradual metamorphosis Feed on wood and plant materials Protozoans digest cellulose Significant structural pest Build distinctive nests

Isoptera (equal wing) (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]

Subterranean termite queen, king, workers and soldier

Nasutiform termite nest in tree. Nasutiform soldiers protecting opened nest.

(incomplete metamorphosis cont’d) Orders of Insects (incomplete metamorphosis cont’d) Mantoidea – mantids Blattodea – cockroaches Hemiptera - true bugs & bug-like insects Thysanoptera - thrips Psocoptera - barklice, booklice Phthiraptera - biting & sucking lice

Order Mantodea (=soothsayer) mantids / praying mantid Large (50-100 mm) Forelegs modified for grasping prey Predatory Chewing mouthparts Gradual metamorphosis

Mantodea (=soothsayer) (mantids, praying mantis; ~1.8K spp.) [front legs raptorial (modified for grasping), prothroax elongated, chewing mouthparts, two short cerci]

Order Blattodea (=L. cockroach) cockroaches Flattened body Long slender antennae Wings thickened, leathery Wings reduced in some species Legs modified for running Chewing mouthparts Gradual metamorphosis Feed on organic matter, stored products, plants

Blattodea (L. cockroach) (cockroaches; <4K spp.) [body flattened and oval, front wings leathery, hind wings folded like a fan, chewing mouthparts, two short cerci]

Order Hemiptera (=half wing) true bugs & bug-like insects Formerly 2 separate orders; recently combined Suborder Heteroptera Suborders Auchenorrhyncha & Sternorrhyncha (former Homoptera)

Suborder Heteroptera the true bugs Piercing/sucking mouthparts Prominent beak arises from front of head Two pairs of wings on most Forewings: thickened front halves Hindwings: membranous Forewings lay flat, overlapping Scutellum (▼-shaped)

Suborder Heteroptera true bugs Many have scent glands Plant feeders, predators, blood feeders Gradual metamorphosis

Hemiptera (s.o. Heteroptera) (half wing) (true bugs; 23K spp.) [front wings half leathery & half membranous; hind wings membranous; usually long antennae; sucking mouthparts arise from front of head]

Suborder Auchenorrhyncha leafhoppers, cicadas & Suborder Sternorrhyncha aphids,whiteflies, scales, psyllids, mealybugs Piercing/sucking mouthparts Beak arises from rear underside of head

Suborders Auchenorrhyncha & Sternorrhyncha Wings: Uniformly textured Some have 4 wings Some have 2 wings (in males of some species) Some have no wings Wings often held roof-like over the body

Suborders Auchenorrhyncha & Sternorrhyncha Gradual metamorphosis All are plant feeders Many are vectors of plant disease

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)

Order Thysanoptera (=fringe wing) thrips (singular & plural!) Small (most <4 mm), elongate Chewing mouthparts Small conical beak Rasping mouthparts Most with 4 wings Strap-like Fringed with long bristles Some species are wingless

Order Thysanoptera (=fringe wing) thrips Plant feeders or predators Flowers are favored Gradual metamorphosis but more intermediate: egg, larva, prepupa, pupa, adult Thrips: only plural form of word!

Thysanoptera (=fringe wing) (thrips; 4.5K spp.) [small; front and hind wings bladelike with hair fringe, often absent; mouthparts modified rasping sucking; antennae short]

Order Psocoptera (=rub wings) psocids, booklice, barklice Small, soft-bodied Front of head bulging Wings present or absent Reduced veins when present Often reduced (brachypterous) Chewing mouthparts Eat molds & mildews Barklice feed on lichens

Psocoptera (=rub small wing) (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]

Order Phthiraptera (=lice without wings) Formerly 2 separate orders Suborder Mallophaga (wool eater): chewing lice Suborder Anoplura (unarmed tail): sucking lice

Order Phthiraptera (=lice without wings), Suborder Mallophaga (=wool eater) chewing lice Small, hard, dorso-ventrally flattened Wingless Chewing mouthparts Head usually broadly rounded & wider than prothorax Gradual metamorphosis Feed mostly on birds, some mammals

Phthiraptera (Mallophaga) (lice without wings) (biting lice; 2.7K spp.) [very flat, small; no wings; chewing mouthparts; external parasites of birds and mammals] Chicken biting louse

Biting louse adult (above) and eggs (right) on goose feathers.

Order Phthiraptera (=lice without wings), Suborder Anoplura (=unarmed tail) sucking lice Small, hard, dorso-ventrally flattened Wingless Piercing/sucking mouthparts Head narrower than prothorax Suck blood of mammals Gradual metamorphosis

Phthiraptera (Anoplura) (sucking lice; 0.3K spp.) [small, flattened; no wings; sucking mouthparts; external parasites of mammals] Human head louse Human crab louse