Immature Insect Identification

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Immature Insect Identification

• Kelly V. Tindall
• Extension Entomologist
• Twin Falls County

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After the Specimen is Collected

• Adults (winged)
• Place in the freezer until it can be delivered
• To keep alive, put food in the container from the
  host on which it was collected
• Also include a moisture source (moist paper
  towel)
• Immatures (non-winged, soft bodied)
• Store in alcohol
• (70 Ethanol is best, isopropyl is okay for short
  term)
• Keep alive by placing in container with food try
  to mimic the environment as closely as possible
• Sometimes easier to key as adults

3
Arthropoda Characteristics

• Exoskeleton
• Chitin
• Segmented appendages
• Segmented body
• Bilateral symetry
• Dorsal tubular heart
• Ventral paired nerve chord

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Classes of Arthropods

• Arachnida spiders, mites, ticks
• Diplopoda millipedes
• Chilopoda centipedes
• Insecta insects

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Arachnida Characteristics
Ticks, mites, spiders, scorpions

• Body divided into two parts
• Four pairs of legs
• No antennae
• No wings

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Chilopoda
Centipedes

• Longer antennae than millipedes
• Flattened in cross section
• 1 pair of legs per segment
• Beneficial prey on other arthropods
• Are fast moving
• Have poison glands can
• inflict a painful bite

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Dilopoda
Millipedes

• Feed on fungi and decaying plants
• Can damage plants
• 2 pair of legs per segment
• 2 visible body parts head and body
• Round in cross section
• Slow moving

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Insecta Characteristics

• Mandibulate
• Mouth consists of mandible, maxilla labia
• 3 body segments
• Head
• Thorax
• Abdomen
• Pair of antenna
• Most have compound eyes

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Orders of Insects

• Collembola spring tails
• Thysanura silver fish
• Ephemerptera maylfies
• Odanota dragonflies
• Phasmida walking sticks
• Orthoptera - grasshoppers
• Mantodea preying mantids
• Blattaria - roaches
• Isoptera - termites
• Dermaptera - earwigs
• Plecoptera - stoneflies
• Psocoptera book bark lice
• Phthiraptera true lice

• Hemiptera true bugs
• Homoptera aphids/hoppers
• Thysanoptera - thrips
• Neuroptera lace wings
• Coleoptera - beetles
• Mecoptera scorpionfly
• Siphonaptera - fleas
• Diptera flies, mosquitoes
• Tricoptera - caddisflies
• Lepidoptera butterfly/moth
• Hymenoptera ants, wasps, bees

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No. of Species per Order
Aprx. 800,000 species
Hymenoptera
Hemiptera
Lepidoptera
Coleoptera
Diptera
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Helpful Hints for Identification

• Pictures
• Specimens from a collection
• Biology
• Habitat soil, wood, plant, food, aquatic
• Sometimes host specific
• Characteristic damage patterns
• Time of year may help
• Rear immatures to adults
• Keys
• Ask the expert

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Characteristics of an Adult

• Head
• Pair of antennae
• Pair of mandibles

• Thorax
• Locomotor appendages
• 3 pairs of true legs
• 1 or 2 pairs of wings

head

• Abdomen
• Genitalia at the end
• Spiracles

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Characteristics of Larvae
Abdomen Prolegs
Thorax (1st 3 segments after head true legs)
Head
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Head of Insect
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Head of Insect
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Head of Insect
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Head of Insect
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Head of Insect
Mouth
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Antennal Types

• Setaceous
• Bristle-like
• Dragonfly

• Filiform
• Thread-like
• Cockroaches
• Ground beetles

• Moniliform
• Bead-like
• Termites

• Serrate
• Sawtoothed
• Click beetles

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Antennal Types

• Clavate
• Gradually clubbed
• Carrion beetles

• Capitate
• Abruptly clubbed
• Butterflies

• Pectinate
• Comb-like
• Male glow-worms

• Geniculate
• Elbowed
• Ants
• Weevils

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Antennal Types

• Lamellate
• Nested plates
• Scarab beetles (June bugs)

• Pulmose
• Feather-like
• Mosquitoes
• Male moths

• Aristate
• Pouch-like with lateral bristles
• Flies

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Mouth Parts
Chewing
Sucking
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Mouth Parts of the Orders

• Chewing
• Collembola
• Thysanura
• Ephemerptera
• Odanota
• Phasmida
• Orthoptera
• Mantodea
• Blattaria
• Isoptera
• Dermaptera
• Plecoptera

• Sucking
• Hemiptera
• Homoptera
• Phthiraptera
• Thysanoptera
• Siphonaptera
• Diptera
• Tricoptera
• Lepidoptera
• Hymenoptera

• Psocoptera
• Phthiraptera
• Neuroptera
• Coleoptera
• Mecoptera
• Siphonaptera
• Diptera
• Tricoptera
• Lepidoptera
• Hymenoptera

Mouthparts are different on immature and adult
forms
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Thorax
Prothorax 1st thoracic segment 1st pair of legs
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Thorax
Mesothorax Middle segment of thorax 2nd pair of
legs 1st pair of wings (forewing), if present
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Thorax
Metathorax Last segment of thorax 3rd pair of
legs 2nd pair of wings (hindwings), if present
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Abdomen

• Multiple segments
• Spiracles present on abdominal segments
• May have appendages on last segment
• Genitalia present on abdomen

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Spiracles

• Used for respiration
• Usually 1 10 pairs
• Can be important for ID purposes (maggot larvae)

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Abdominal Appendages
Mayfly

• Cerci
• Paired abdominal segments
• Sensory or defensive in nature
• Often reduced or retracted into the body

• Cornicles
• Tubular structures on the 5th or 6th segment
• Secrete defensive fluids

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Metamorphosis

• Simple
• external wing development (if winged), no period
  of inactivity
• Ametabolous
• Hemimetabolous
• Paurometabolous
• Intermediate
• External wing pads internal development, period
  of inactivity
• Complete
• Internal wing development, period of inactivity

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Simple Metamorphosis
Ametabolous Immatures look identical to adult
only smaller (silverfish)
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Simple Metamorphosis
Hemimetabolous Immatures (niads) look different
than adult NO PUPA (mayflies and odanates)
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Simple Metamorphosis

• Paurometabolous
• Immatures (nymphs) look similar to adult
• Gradual development of wing pads externally
• Homoptera, Hemiptera other orders

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Incomplete Metamorphosis

• Intermediate
• Immatures (nymphs) look similar to adult
• Some internal wing development
• prepupal and pupal stages (period of inactivity)

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Complete Metamorphosis

• Holometabolous
• Immatures (larvae/ maggots) look different than
  adult
• Pupa formed
• Bettles, diptera, lepidoptera, hymenoptera)
• Internal wing development

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Type of Metamorphosis by Order

• Simple (A)
• Collembola
• Thysanura

• Simple (P)
• Phasmida
• Orthoptera
• Mantodea
• Blattaria
• Isoptera
• Dermaptera
• Psocoptera
• Phthiraptera
• Hemiptera
• Homoptera
• Psocoptera

• Intermediate
• Thysanoptera

• Complete
• Neuroptera
• Coleoptera
• Mecoptera
• Siphonaptera
• Diptera
• Tricoptera
• Lepidoptera
• Hymenoptera

• Simple (H)
• Ephemerptera
• Odanota
• Plecoptera

A ametabolous H hemimetabolous P
paurometabolous
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Larval Types

• Scarabaeiform
• Grub-like
• Usually curved (C-shaped)
• Well developed head
• Thoracic legs, NO prolegs

• Elateriform
• Wireworm-like
• Elongate body
• Cylicrical
• Hardshelled
• Short legs

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Larval Types

• Vermiform
• Maggot-like, worm-like
• Legless
• With or without a developed head

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Larval Types

• Eruciform
• Caterpillar-like
• Cylindrical body
• Well developed head
• Short antennae
• Thoracic and prolegs

• Campodeiform
• Elongate body
• Somewhat flattened
• Usually well developed antennae
• Active

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Larval Types by Order

• Eruciform
• Lepidoptera
• Mecoptera
• Hymenoptera

• Campodeiform
• Neuroptera
• Tricoptera
• Coleoptera

• Vermiform
• Diptera
• Siphonaptera
• Hymenoptera
• Coleoptera
• Lepidoptera

• Scarabaeiform
• Coleoptera

• Elateriform
• Coleoptera

Not the most common larval form of the order
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Pupal Types

• Obtect
• Appendages more or less glued to body
• May be covered by cocoon
• Lepidoptera, some Diptera

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Pupal Types

• Exerate
• Appendages free
• Not covered by cocoon
• mummified adult
• Most insects with complete metamorphosis NOT
  Lepidopteran or Diptera

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Pupal Types

• Coarctate
• Like exerate but covered with hardened cuticle
• Some Diptera

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Orders of Insects

• Collembola spring tails
• Thysanura silver fish
• Ephemerptera maylfies
• Odanota dragonflies
• Phasmida walking sticks
• Orthoptera - grasshoppers
• Mantodea preying mantids
• Blattaria - roaches
• Isoptera - termites
• Dermaptera - earwigs
• Plecoptera - stoneflies
• Psocoptera book bark lice
• Phthiraptera true lice

• Hemiptera true bugs
• Homoptera aphids/hoppers
• Thysanoptera - thrips
• Neuroptera lace wings
• Coleoptera - beetles
• Mecoptera scorpionfly
• Siphonaptera - fleas
• Diptera flies, mosquitoes
• Tricoptera - caddisflies
• Lepidoptera butterfly/moth
• Hymenoptera ants, wasps, bees

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Hemiptera vs Homoptera

• Mouthparts arise at end of head
• Elongate, filiform antennae

• Mouthparts arise on underside of head
• Long, filiform OR bristle-like antennae

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True Bugs
Nymphs
Leaf-footed bug
Plant bug
Assassin bug
Stink bug
Bed bug
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Hoppers, Aphids, etc
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Coleoptera
Beetles Weevils

• Largest order of insects
• Usually two pairs of wings
• Front pair are thick (elytra)
• Straight line down the middle of back
• Plant feeders, predators, scavengers, wood
  borers, etc

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Beetle Larval Characteristics

• Body type variable
• Mouthparts chewing, opposable mandibles
• Eyes 6 stemmata
• Antennae 4 segments or less
• Head Well-developed no Y- or V-shaped sutures
• Legs usually 5-6 segments
• Abdomen usually 10 segments no prolegs

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Beetles
Dermestid
Leaf beetles
Weevil
Ladybird beetle
White grub
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Diptera
True Flies, Mosquitoes, Gnats, Midges

• Winged or wingless
• One pair of membranous wings one pair halteres
• Few feed on plant foliage
• Some of the most beneficial insects
• Beneficial as pollinators, parasites predator,
  stings are a nuisance

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Fly Larval Characteristics

• Body type vermiform lacks legs
• Mouthparts mandibles bearing teeth to
  sickle-shape mandibles
• Head well developed and exposed to partially or
  completely retracted into thorax
• Eyes stemmata may be present
• Antennae 1-6 segments, usually 3
• Legs absent
• Abdomen 10-12 segments, may have prolegs or
  creeping welts

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Flies Retracted Heads
Deer Fly
Warble fly
Blow Fly
Leaf miners
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Flies Partially Retracted Head
Syrphids (flower fly)
Bot Fly
Soldier Fly
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Flies Well-developed Heads
Mosquito
Black Fly
Midge/ Bloodworm
No-see-ums
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Hymenoptera
Ants, bees, wasps, hornets, sawflies

• Winged or Wingless
• Two pair of membranous wings
• Few feed on plant foliage
• Many beneficial insects - pollinators, parasites
  predators
• Stings are a nuisance
• Complete metamorphosis
• Many social insects

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Bee/Wasp/Ant Larval Characteristics

• Body type vermiform lacks legs OR
  caterpillar-like
• Mouthparts mandibulate, working in horizontal
  plane
• Head well developed OR retracted into thorax
• Eyes single pair of stemmata if present
• Antennae short, 1-7 segments
• Legs absent, may have prolegs or creeping welts
• Abdomen 10-12 segments, may have prolegs 5 (no
  crochets)

Parasitic wasps
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Ants, Bees Wasps
Parasitic wasps
Ants
Bees
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Sawflies
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Lepidoptera
Moths Butterflies

• Four well-developed wings
• Wings have overlapping scales
• Caterpillars on leaves of plants
• Leaf feeders
• Some are pests most are benign

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Lep. Larval Characteristics

• Body type eruciform
• Mouthparts chewing
• Head well developed V- or Y-shaped adfrontal
  sutures
• Eyes 6 stemmata
• Antennae short
• Legs usually well-developed
• Abdomen 10 segments, prolegs 5 with crochets

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Leps - Moths
Inch worm
Bagworms
Hornworm
Looper
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Leps - Moths
Tussock moth
Tent caterpillars
Wooly Bear
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Noctuidae
Armyworm
Corn earworm
Black cutworm
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Leps - Butterflies
Monarch
Skipper
Brushfoot
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Heads of Caterpillar-Like Larvae
Beetles
Lepidoptera
Sawfly
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Leps vs Sawflies

• 5 prolegs
• Crochets

• gt5 prolegs
• No crochets

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Crochets
Hook-like structures on prolegs
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Leps vs Sawflies

• 5 prolegs
• Crochets
• Adfrontal sutures
• Setal hairs on body

• gt5 prolegs
• No crochets
• No adfrontal sutures
• Wrinkly skin

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Isoptera
Termites

• Small, soft bodied
• Yellowish or whitish insects
• Wide waist, bead-like antennae (not bent)
• Liven in colonies in wood
• Three castes workers, soldiers and reproductives
• Structural pests

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Ants vs Termites

• Elbowed antennae

• Bead-like antennae

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Ants vs Termites

• Elbowed antennae
• Complete metamorphis

• Bead-like antennae
• Simple metamorphis

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