Introduction to Phylum Arthropoda

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Introduction to Phylum Arthropoda
Dr. Vera Krischik, Department of Entomology,
University of Minnesota
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Phylum Arthropoda

• Segmented body.
• Paired segmented appendages.
• Bilateral symmetry.
• Chitinous exoskeleton.
• Tubular alimentary canal with mouth and anus.
• Open circulatory system, a tubular dorsal blood
  vessel.
• Body cavity or coelom.
• Nervous system of anterior ganglia and paired
  nerve cords.
• Striated muscles in skeletal system.
• Respiration by gills, tracheae, or spiracle.

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Phylum Arthropoda

• Insects
• Arachnids (spiders, ticks, mites, etc.)
• Crustaceans
• Millipedes
• Centipedes

Cottonwood Leaf Beetle,Chrysomela scripta
CUES, http//www.entomology.umn.edu/cues/IPM-turf/
sodwebworms.htm
Sod Webworm Moth, Crambus sp.
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Class Crustacea Crabs, lobsters, sowbugs

• Two main body sections.
• Five to seven pairs of legs.
• Twopairs ofantennae.
• Simpleeyes.

O.F.A.H.http//www.invadingspecies.com/
Crayfish
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Class Crustacea Crabs, lobsters, sowbugs
Pillbugs
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Class Chilopoda Centipedes

• One pair of legs per body segment.
• Flattened body.
• First pair of legs modified as venomous fangs.
• Nocturnal predators.
• Few are dangerous to humans.

Garden Centipede,Lithobius forficatus
Department of Entomology,University of
Nebraska-Lincoln
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Class Chilopoda Centipedes
Georgia ForestryCommission ArchivesGeorgia
ForestryCommissionwww.forestryimages.org
Fangs of Scolopendrid Centipede (above)House
Centipede,Scutigera coleoptrata (right)
Department of Entomology,University of
Nebraska-Lincoln
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Class Diplopoda Millipedes

• Two pairs of legs per body segment.
• Cylindrical body.
• Feed ondecayingplantmaterial.
• Nocturnal.
• Harmless.

Emily G. Tenczar
Pet African Giant Millipedes
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Class Diplopoda Millipedes
Photos by William Leonard, Tree of Life Web
Project, http//tolweb.org/tree/phylogeny.html
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Class Arachnida Spiders, ticks, mites,
harvestman, scorpions, etc.
Tick
Mite
Yellow Garden Spider
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Class Arachnida
Ronald F. BillingsTexas Forest
Servicewww.forestryimages.org

• Mouthparts are calledchelicerae.
• Most contain venom.
• Antennae are absent.
• Four pairs of legs.
• Book lungs for respiration.

Blacklegged Tick, Ixodes scapularis
Yellow Garden Spider,Argiope aurantia
Scott Bauer, USDA Agricultural Research Service,
www.insectimages.org
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Class ArachnidaOrder Araneae Spiders

• Two body regions(cephalothorax, abdomen).
• Fangs (chelicerae), mostare venomous.
• Most are not dangerous.
• Most make webs.
• Most have poor eyesighthairs compensate for
  it(jumping spiders are an exception).
• Potentially dangerous spiders (bites are
  uncommon) Brown recluse spider, Black widow
  spider

David Cappaert, www.insectimages.org
Jumping Spider, Phidippus audax
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Class ArachnidaOrder Araneae Spiders
David Keith, Department of EntomologyUniversity
of Nebraska-Lincoln
Crab Spider,Misumenoides formosipes
Wolf Spider,Lycosa carolinensis
James O. Howell, The University of Georgia,
www.forestryimages.org
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Class ArachnidaOrder Opiliones Harvestman
(Daddy Longlegs)

• One apparent bodyregion.
• Abdomen andcephalothorax short.
• Common and harmless.
• Nocturnal.
• Feed on detritus, fruit,or other animals.

Leiobunum sp.
Joseph Berger, www.insectimages.org
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Class ArachnidaOrder Scorpiones Scorpions

• Long tail with sting.
• Pedipalps are modifiedas pinchers.
• Most scorpion stingsare no worse than
  beestings only a minorityof species
  arepotentially dangerous.
• Nocturnal.
• Common in warmclimates.
• Feed on other animals.

E. Tenczar
Striped Bark Scorpion, Centruroides
vittatus,gravid female from Texas
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Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
E. Tenczar
Emperor Scorpion,Pandinus imperator,female
eating cockroach, native to West Africa
Northern Desert Hairy Scorpion, Hadrurus spadix,
native to US
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Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
Arizona Bark Scorpion, Centruroides exilicauda,
mating
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Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
E. Tenczar
Flat Rock Scorpion,Hadogenes troglodytes,female,
native toSouth Africa
Lined Devil Scorpion,Vaejovis spinigerus,female
from Arizona with young
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Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
Slenderbrown Bark Scorpion,Centruroides
gracilis,male from Central America
E. Tenczar
Pandinus imperator scorpions glow under UV/
black light
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Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
E. Tenczar
Black Thick-Tailed Scorpion, Parabuthus
transvaalicus, a highly venomous species native
to South Africa
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Class Arachnida Order Acari Ticks

• Ticks have two body regions.
• Young have six legs, adults have eight.
• There are hard and soft-bodied ticks.
• Ticks are much larger than mites, some females as
  large as a nickel.

Jim Occi, BugPics, www.insectimages.org
Blacklegged Tick, Ixodes scapularis
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Class ArachnidaOrder Acari Chiggers (Juvenile
Mites)

• Attach to skin using twoclaws.
• Two blade-like beaks enterthe skin.
• Injected fluid dissolves skintissue around
  beaks, buthardens surrounding tissue so that a
  stylostome, or tube is formed.
• Chigger sucks up liquid through stylostome.
• Tube remains after chigger leaves, causing
  itching.

Chigger Bites on Human
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Class ArachnidaOrder Acari Mites

• Mites have only one noticeable body region.
• Many are microscopic or close to it.

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Mites

• Egg, larva, protonymph, deutonymph, adult.
• Four pair legs three pairs on larvae.
• Two body segments head, thorax.
• Chelicerae fangs like spiders.
• Suck cells.
• Cause chlorosis yellowing of foliage.
• Transmit disease.
• Diagnostics chlorosis, webbing, rusetting, galls.

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Mites

• Female round abdomen
• Male pointed abdomen
• Larva 3 pairs of legs

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Epiclass HexapodaInsects, springtails,
diplurans, proturans

• Three distinct bodyregions head,
  thorax,abdomen.
• One pair antenna.
• One pair of mandibles.
• One pair of maxillae.
• Three pairs of legs onthorax.
• Tracheal respiratory system- composed of tubes
  with holes (spiracles) through the body that
  admit air.

Japanese Beetle,Popillia japonica
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Class EntognathaOrder Diplura Diplurans
David R. Maddison, Tree of Life Web
Projecthttp//tolweb.org/tree/phylogeny.html

• Ametabolous simplemetamorphosis.
• Two caudal filaments.
• Compound eyes.
• Antennae.
• Wingless adults.
• Difference between nymphs and adults is size.
• Feed on decomposing materials.

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Class Insecta Insects

• Protruding mouthparts, unlike non-insect
  hexapods.
• Ametabolous, hemimetabolous, parametabolus, or
  holometabolous.
• Most have wings.

David Cappaert, www.insectimages.org
Milkweed Leaf Beetle, Labidomera clivicollis
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Class Insecta Pterygota Winged Insects

• Most adult forms have wings.
• Hemimetabolous, parametabolus, or holometabolous.

Polyphemus Moth, Antheraea polyphemus
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Class InsectaOrder Ephemeroptera Mayflies
Tree of Life Web Project http//tolweb.org/tree/ph
ylogeny.html

• Hemimetabolousmetamorphosissimple, incomplete.
• Winged adults live for a day.
• Wings at rest held over body.
• 2-3 caudal filaments.
• Nymphs and adults in different habitat.
• Nymphs and adults different in appearance.
• Aquatic nymphs with gills.
• Indicate good water quality.

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Class InsectaOrder Odonata Dragonflies and
damselflies

• Hemimetabolous metamorphosis simple, incomplete.
• Toothed mandibles (chewing mouthparts).
• Winged adults.
• Nymphs and adults different in appearance.
• Aquatic nymphs with gills.
• Indicate good water quality.

David Cappaert, www.insectimages.org
Damselfly
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Class Insecta Pterygota, Neoptera

• These insects can fold their wings back over the
  body.
• Hemimetabolous, parametabolus, or holometabolous.

Green Stink Bug, Acrosternum hilare
David Cappaert, www.insectimages.org
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Class InsectaOrder Plecoptera Stoneflies

• Hemimetabolous metamorphosissimple, incomplete.
• Folded wings.
• Winged adults.
• Chewing mouthparts.
• Aquatic, gillednymphs.

Triznaka signata adult (top), Perlesta
decipiensnymph (bottom)
C. Riley Nelson Tree of Life Web
Projecthttp//tolweb.org/tree/phylogeny.html
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Class Insecta Pterygota, NeopteraPaurometabolou
s/gradual Metamorphosis

• Walkingsticks
• Grasshoppers and crickets
• Mantids
• Cockroaches
• Termites
• Earwigs

• Stoneflies
• Lice
• True Bugs
• Cicadas, hoppers and aphids
• Thrips

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Class InsectaOrder Phasmatodea Walkingsticks

• Paurametabolous metamorphosis gradual.
• Winged adults.
• Chewing mouthparts.
• Nymphs and adults in same habitat.
• Nymphs and adults similar in appearance.

Herbert A. "Joe" Pase III, Texas Forest Service,
www.insectimages.org
Anisomorpha sp.
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Class Insecta Order Orthoptera Grasshoppers,
katydids, and crickets

• Paurametabolousmetamorphosis gradual.
• Straight wings.
• Winged adults.
• Chewing mouthparts.
• Nymphs and adults in same habitat.
• Nymphs and adults similar in appearance.

Redlegged Grasshopper,Melanoplus femurrubrum
Russ Ottens, The University of Georgia
www.insectimages.org
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Class InsectaOrder Mantodea Mantids
Clemson Universityhttp//entweb.clemson.edu/cuent
res/cesheets/benefici/ce178.htm

• Paurametabolousmetamorphosisgradual.
• Winged adults.
• Chewing mouthparts.
• Nymphs and adults insame habitat.
• Nymphs and adultssimilar in appearance.

Praying Mantis
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Class InsectaOrder Blattaria Cockroaches

• Paurametabolous metamorphosis gradual.
• Winged adults.
• Chewing mouthparts.
• Nymphs and adults in same habitat.
• Nymphs and adults similar in appearance.

Clemson University - USDA Cooperative Extension
Slide Series www.insectimages.org
American Cockroach, Periplaneta americana
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Class InsectaOrder Isoptera Termites

• Paurametabolousmetamorphosisgradual.
• Equal wings.
• Winged adults.
• Chewingmouthparts.
• Nymphs andadults in samehabitat.
• Nymphs and adults similar in appearance.

Gerald J. Lenhard, www.insectimages.org
Formosan Subterranean Termite,Coptotermes
formosanus
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Class InsectaOrder Dermaptera Earwigs

• Paurametabolous metamorphosis gradual.
• Skin-like front wings.
• Winged adults.
• Chewing mouthparts.
• Nymphs and adults in same habitat.
• Nymphs and adults similar in appearance.

Striped Earwig,Labidura riparia
Joseph Berger, www.insectimages.org
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Class Insecta Order Phthiraptera (Mallophaga and
Anoplura) Lice

• Paurametabolous metamorphosis gradual.
• Wingless adults.
• Chewing or suckingmouthparts.
• Nymphs and adultsin same habitat.
• Nymphs and adultssimilar in appearance.

Sucking Louse,Haematopinus eurysternus
Iowa State University''s Entomology Image Gallery
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Class Insecta Order HemipteraSuborder
Heteroptera True bugsSuborder Sternorrhyncha
Aphids, whiteflies, scalesSuborder
Auchenorrhyncha Cicadas, hoppers

• Paurametabolous metamorphosis gradual.
• Usually winged adults.
• Sucking mouthparts.
• Nymphs and adults in same habitat.
• Nymphs and adults similar in appearance.
• Sternorrhyncha and Auchenorrhyncha used to be
  classified in Order Homoptera.

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Class Insecta Order HemipteraSuborder
Heteroptera True bugs

• Most bugs feed on plants.
• Some are predaceous.

CUES, http//www.entomology.umn.edu/cues/dx/vk/fou
rbug.htm
CUEShttp//www.entomology.umn.edu/cues/dx/vk/whit
emark.htm
Predaceous Stink Bug attacking caterpillar
Fourlined Plant Bug, Poecilocapsus lineatus
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Order Hemiptera Suborder Sternorrhyncha Soft
Scale (formerly in Order Homoptera)
Gerald J. Lenhard, www.insectimages.org
Summer Male
Summer Female and Crawlers
Tuliptree Scale,Toumeyella liriodendri Linden,
walnut
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Order Hemiptera Suborder Sternorrhyncha Armored
Scale (formerly in Order Homoptera)
Clemson University - USDA Cooperative Extension
Slide Series, www.insectimages.org
Euonymus Scale, Unaspis euonymi
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Order Hemiptera Suborder Auchenorhyncha Cicadas,
hoppers (formerly Order Homoptera)
Spittlebug
Leafhopper
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Class Insecta Order Thysanoptera Thrips
Alton N. Sparks, Jr., The University of Georgia,
www.insectimages.org

• Paurametabolousmetamorphosisgradual.
• Fringe-winged.
• Winged adults.
• Nymphs and adultsin same habitat.
• Nymphs and adultssimilar inappearance.

Onion Thrips, Thrips tabaci
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Class Insecta Pterygota, Neoptera,
Endopterygota Holometabolous/complete
metamorphosis

• Lacewings
• Beetles
• Scorpionflies
• Fleas
• Flies
• Caddisflies
• Moths andbutterflies
• Sawflies, wasps,and bees

Herbert A. "Joe" Pase III, Texas Forest Service,
www.insectimages.org
Forest Tent Caterpillars, Malacosoma disstria
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Class Insecta Order NeuropteraLacewings,
antlions, owlflies
Bradley Higbee, Paramount Farming,
www.insectimages.org
Green Lacewing, Chrysoperla sp., Adult (left) and
Larva (right)
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Class Insecta Order NeuropteraLacewings,
antlions, owlflies

• Holometabolous metamorphosis complete.
• Nerve-winged.
• Winged adults.
• Chewing mouthparts.
• Larvae and adults sometimes in same habitat.
• Some larvae are aquatic.
• Larvae and adults not similar in appearance.

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Class InsectaOrder Coleoptera Beetles
Japanese Beetle,Popillia japonica, Adult
(left)and Scarab Larva (below)
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Class InsectaOrder Coleoptera Beetles

• Holometabolous metamorphosis complete.
• Hardened forewings (elytra).
• Winged adults.
• Chewing mouthparts.
• Larvae and adults in same habitat.
• Larvae and adults not similar in appearance.

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Class InsectaOrder Mecoptera Scorpionflies
University of Minnesotahttp//www.entomology.umn.
edu

• Holometabolousmetamorphosiscomplete.
• Long wings.
• Winged adults.
• Larvae and pupaesometimes found in soil.
• Larvae and adults not similar in appearance.

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Class InsectaOrder Siphonoptera Fleas
David R. Maddison, Tree of Life Web
Projecthttp//tolweb.org/tree/phylogeny.html

• Holometabolousmetamorphosiscomplete.
• Wingless adults.
• Sucking mouthparts.
• Larvae and adultsnot similar inappearance.
• Often pests of mammals.

Oriental Rat Flea, Xenopsylla cheopis
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Class InsectaOrder Diptera Flies
Michigan State Universityhttp//www.msue.msu.edu/
vanburen/fappmag.htm
Fly Larva (maggot)
Tachinid Fly Adult
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Class InsectaOrder Diptera Flies

• Holometabolous metamorphosis complete.
• Winged adults.
• 2nd pair of wings are halteres.
• Larvae and adults often in same habitat.
• Larvae and adults not similar in appearance.
• Some spread diseases to humans and livestock.
• Some are parasitoids.

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Class InsectaOrder Trichoptera Caddisflies

• Holometabolousmetamorphosiscomplete.
• Winged adults.
• Aquatic larvaeconstruct and livein tubes.
• Larvae and adultsnot similar inappearance.
• Indicators of waterquality.

David Funk
Tree of Lifehttp//tolweb.org/tree/phylogeny.html
James C. Hodges, Jr.
Caddisfly Adult (top) and Larvae (bottom)
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Class InsectaOrder Lepidoptera Moths and
butterflies
Cankerworm Larvae (right)and Adult (below)
CUEShttp//www.entomology.umn.edu/cues/dx/vk/cank
er.htm
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Class InsectaOrder Lepidoptera Moths and
butterflies

• Holometabolous metamorphosis complete.
• Winged adults.
• Larvae and adults not similar in appearance.
• Most larvae feed on plant tissue.
• Many moths are pests most butterflies are not.

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Class InsectaOrder Hymenoptera Sawflies,
wasps,bees, ants
John H. GhentUSDA Forest Servicewww.forestryimag
es.org
CUES, http//www.entomology.umn.edu/cues/dx/sk/pin
e11.htm
Introduced Pine Sawfly, Diprion similis, Adults
(left) and Larva (right)
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Class InsectaOrder Hymenoptera Sawflies,
wasps, bees, ants

• Holometabolous metamorphosis complete.
• Membranous wings.
• Winged adults.
• Larvae and adults not similar in appearance.
• Sawflies are phytophagous.
• Some wasps are parasitoids.
• Many wasps, bees, and all ants are social.