Entomology LECTURE2 (1).pptx

Linnaean Classification System
• A way to impart order to a complex environment
• Species is the basic unit of biological classification
• Genus represents a group of closely related species
• Family represents a group of closely related genera
• Order represents a group of closely related genera
• Etc., etc., etc.

Insect are successful in diversity
 Insects possess an amazing diversity
in size, form, and behavior.
 Protective shell or exoskeleton,
they are small, and they can fly.
 Small size and ability to fly permits
 Escape from enemies dispersal to
new environments.
 The Ant: A Most Successful Insect

 Insects are the dominant life-form on earth.
 Millions may exist in a single acre of land. About one million species
have been described, and there may be as many as ten times that many
yet to be identified.
 Of all creatures on earth, insects are the main consumers of plants.
 Play role in the breakdown of plant and animal material
 Food source for many other animals
 Insect populations also possess considerable genetic diversity
 A great potential for adaptation to different or changing environments

Arthropods, and Related Phyla
• Annelids (Segmented Worms)
– Segmented bodies
– No legs
– Appendages in the head (jaws, feelers, etc.)
• Onychophorans (Velvet Worms)
– Long, soft-bodied, carnivorous worms
– Head with eyes, rasping jaws
– Unjointed ‘lobopodia’
• Arthropods

Annelids: Segmented Worms
– Segmented bodies
– No legs
– Appendages in the head
(jaws, feelers, etc.)
Annelid: Earthworm
Annelid: Leech
Annelid: Polychaete

Onychophorans: Velvet Worms
– Long, soft-bodied, carnivorous worms
– NEMATODES ( intestinal parasites)
– Head with eyes, rasping jaws
– Unjointed ‘lobopodia’
Image Source:
http://www.ucmp.berkeley.edu/annelida/nereid.gif
Image Source:
http://www.britannica.com/eb/art-6767/Onychophoran

The Arthropod Phylum
• A phylum is a major group of organisms.
• Insects are a Class in the Phylum of
Arthropods.
• Characteristics of Arthropods Include:
– Segmented Bodies
– Jointed Legs
– Exoskeleton
– Open Circulatory System
– No Backbone
– Bi-lateral Symmetry

Phylogeny of
Major Groups
Defined by embryology
Blastopore becomes anus
Defined by:
Exoskeleton
Jointed legs
Time

Major Groups of Arthropods
• Class Xiphosura
– Common Name: Horseshoe Crabs
• Class Arachnida
– Includes Scorpions, Spiders and Mites
• Subphylum Mandibulata
– Includes Crustaceans, Millipedes, Centipedes
• Class Insecta

Major Classes of Arthropods
Class Xiphosura
(Common Name: Horshoe Crabs)
• No antennae
• Two distinct body
divisions
– Body with broadly oval
shell and long, slender tail
– Abdomen with leaf-like
gills on ventral side
• First pair of appendages
are chelicera
• All are aquatic
Image Source:
http://paleo.cortland.edu/tutorial/Arthropods/Arthropod%20Images/horseshoe.GIF

Class Arachnida
• Two distinct body divisions
• 4 pair of legs
• First pair of appendages are chelicerae
• No antennae
Chelicerae
Photo Images Courtesy of: Dept. of Entomology, University of Nebraska-Lincoln

Class Arachnida: Order Araneida
(Common Name: Spiders)
• Two distinct body divisions, 8 true legs
• All possess venom glands and spinnerets
• Pedipalps in male are modified for sperm
Photo Images Courtesy of: Dept. of Entomology, University of Nebraska-Lincoln
Spinnerets
Chelicerae
delivery
Pedipalps
(male)

Class Arachnida: Order: Scorpionida
Common Name: Scorpions
• Relatively large arachnids
• Pedipalps are large and claw-like
• Abdomen distinctly segmented, and ending in a sting
• Found in arid regions in the South and West
Segmented
Abdomen
Cephalothorax
Pedipalps
Sting
Photo Image Courtesy of: Dept. of Entomology, University of Nebraska-Lincoln

Class Arachnida: Order Acarina
Common Name: Ticks & Mites
• No true head
• All ticks are parasites of warm-blooded animals
• Mites are abundant in the soil and debris, but may also be
parasitic
Photo Image Courtesy of:
Virginia Cooperative Extension Service
http://www.ext.vt.edu/departments/entomology/ornamentals/spidermites.html
European Red Mite
Two-Spotted Spider Mite

Subphylum Mandibulata, Class Crustacea
Common Name: Crustaceans
• Two pair of antennae
• At least 5 pairs of legs
• Two distinct body regions (cephalothorax and abdomen)
– Cephalothorax is covered by a hardened hood (carapace)
• Most are detritivores, with some predaceous habits
• Most are aquatic
– Lobsters, shrimp, barnacles, isopods, sowbugs, brine shrimp (sea
monkeys)

Subphylum Mandibulata, Class Diplopod
Common Name: Millipedes
• Worm-like and cylindrical
• Two pair of legs per body segment
• Some secrete cyanide as a chemical defense
• All are detritivores

Subphylum Mandibulata, Class Chilopoda
Common Name: Centipedes
• Worm-like and enlongate
• One pair of legs per body segment
• First pair of legs is modified into poison claws (fangs)
• Predaceous on insects and other small arthropods

Subphylum Mandibulata, Class Symphyla
Common Name: Garden Centipedes
• Similar to centipedes, but with only 10-12 pair of legs
• Closely related to insects
– 5 segmented head
– Labium similar to insects
– Bead like antennae
• Can be pests of field crops
Symphylan Centipede
Millipede

Class Insecta
Common Name: Insects!!!
• Most adult insects have the following characters:
– All have body divided into three parts (head,
thorax and abdomen)
– All have three pairs of legs
– Usually one pair of antennae and a pair of
compound eyes (a few exceptions to these
characteristics are found)
– Usually two pairs of wings
• absent in many insects such as lice, fleas, ants; flies
have one pair of wings)

Characteristics of Class Insecta
• Phylum: Arthopoda
– Class: Insecta
• Order: Diptera (flies)
– Family: Asilidae (robber flies)
Image Source:
http://pest.ca.uky.edu/EXT/Master_gardener/entbasics/introduction/introduction.shtml

Trends History of Arthropods
• Segmented tube with parapodia (Annelids)
• Legs developed with muscles
(Onychophora)
• Segmented or jointed legs (Arthropods)
• Tagmosis: division of body into specialized
units (Arthropods)
• Specialized leg units (Arthropods)
• Loss of leg pairs (Insecta)

Module Objectives
• Part I
– Explain the hierarchical classification system used in biology.
– Name the principle characteristics used to separate the phyla
and classes of insects and their relatives.
• Part II
– Review the general anatomy of insects
– Review the major types of insect life cycles, and the associated
stages of development.
– Review the common orders of insects.
• Part III
– Discuss insect collection techniques
– Current ecological research on pollinators in gardens
• Part IV
– How to diagnose insect problems

Insect External Anatomy
• 3 Body Regions
– Head: Sensory Center
– Thorax: Locomotory Center
– Abdomen: Reproductive Center
Image Source:
http://www.cartage.org.lb/en/themes/Sciences/Zoology/Insects/InsectAnatomy/Introduction/insectanatomy.gif
Image Source:
http://pest.ca.uky.edu/EXT/Master_gardener/entbasics/introduction/introduction.shtml

Head
• Mouthparts (paired mandibles, maxillae and labium)
– Labrum/clypeus as ‘upper lip’
–Maxillary palp and labial palp
are both part of maxillae
Md = mandibles
Lr=labrum
Mx=maxillae
Image Source:
http://www.answers.com/topic/evolution-insect-mouthparts-png
Chewing
Piercing/
Sucking Sucking/
Lapping

Head
• Antennae (1 pair)
• Compound Eyes (1 pair)
• Simple Eyes or Ocelli (3 total)
• Mouthparts (paired mandibles, maxillae and labium)
– Labrum/clypeus as ‘upper lip’
–Maxillary palp and labial palp
are both part of maxillae
Image Source:
http://www.ndsu.nodak.edu/entomology/topics/images/heads.gif

Thorax
• Pro-, meso- and meta-thorax
– Each segment bears a pair of legs
– Meso- and meta-thorax each bear a pair of
wings
Image Source:
http://bugs.bio.usyd.edu.au/Entomology/images/Topics/extMorphology/thoraxComponents.gif

Abdomen
• Cerci and external reproductive
appendages
– Ovipositor in females
Cerci/Pincers
Ovipositor

Objectives
• Part I
• Part II
• Part III
• Part IV

Insect Life Cycles
• Ametabolous: no obvious difference
between juveniles and adults
• Hemimetabolous: nymphs look like
smaller version of adult, without wings
• Holometabolous: nymphs look worm like
or grub like (without wings). Very different
from adult appearance

Ametabolous Development
• Juveniles resemble adults, except that they are
smaller
• With each molt, abdominal segments are added

Hemimetabolous Development
• Juveniles (called nymphs) resemble adults,
except that they are smaller, and do not have
wings
– Development of wing buds or wing pads in later
stages
• With each molt, wing buds get larger

Holometabolous Development
• Juveniles (called larvae) look quite different from adults
– Worm like
– Grub like
– Caterpillar like
• Pupal stage, where metamorphosis occurs
• Juvenile and adult stages often feed on very different things
and/or live in very different habitats

Insect Life Cycles
• Juveniles
– Not winged / can’t fly
– Not sexually mature
• Adults
– Winged / can fly
– Sexually mature
Monarch Butterfly
Potato Leafhopper Adult
Monarch Butterfly Larva
Potato Leafhopper Nymph
No Wings
Wing Pads
Wings
Image Sources:
(Lepidoptera: http://www.museum.vic.gov.au/bugs/life/butterflies.aspx)
(Hemiptera: http://www.ipm.uiuc.edu/cropsci270/syllabus/images/0207image13.jpg)
Wings

Modifications and Insect Diversity
• Waxy, Rigid Cuticle
• Increased number of sclerites
• Tracheal structures
• Dispersal by flight
• High reproductive potential
• Small size
• Lack of competition on land
• Complete metamorphosis

Insect Diversity
• Most diverse class, order, family of organisms

Common Insect Orders
• 31 Insect Orders
– Most recent discovery in 2002! (Mantophasmatodea)
• Orders of particular interest to gardeners
include:
– Coleoptera, Dermaptera, Diptera, Hemiptera,
Hymenoptera, Lepidoptera, Neuroptera, Orthoptera,
Thysanoptera
• ‘-ptera’ means ‘wing’ (think Pteradactyl)
– To ID almost all insects to order, you should look at
the wings of the adults
– Juvenile IDs are much more difficult

Classification of Insect Orders
• Gullan and Cranston. 1994. The Insects: An
Outline of Entomology. Chapman and Hall,
London.
• Borror, Triplehorn and Johnson. 1989. An
Introduction to the Study of Insects. 6th Edition.
Harcourt Brace Jovanovich, Orlando.
• Borror and White. 2004. Introduction to the
Study of Insects. 7th Edition. Brooks Cole.

Primitive Insects
• Ametabolous Development
• No wings (Apterygotes)
• Development of eyes occurs in this group
• Development of spiracles

Proturans and Diplurans
• Ametabolous, No Wings
• No eyes
• Some breath through
cuticle
• Proturans: no antennae,
sucking mouthparts, very
small and rare, found in
moist habitats
• Diplurans: antennae with
internal muscles, chewing
mouthparts, small,
uncommon, found in moist
habitats. Abdomen with
11 segments and 2 cerci.

Collembola
• Ametabolous, no wings
• Antennae with internal muscles
• Some species have eyes. Some
species don’t
• Abdomen has scales, collophore
on 1st segment, retinaculum on
3rd segment and furcula on 4th
segment
• Extremely abundant in certain
soil habitats (moist and with
much organic debris)
• Occasional pests in potted
plants, greenhouses.
• Important food source for many
arachnids and other insects.

Thysanura (silverfish, bristletails)
• Ametabolous, no wings
• Antennae very long and without
internal muscles
• Well-developed eyes
• Breath through spiracles
• Abdomen with 11 segments, 3
bristly cerci
• Mating rituals.
• Habitats include moist, shady
locations outside and hot, dry
locations indoors.
• Feed on starchy substances.
Can be indoor pests on
wallpaper, books, cereals.

Paurometabolous Insects
• Hemimetabolous Development with a
subimago or subadult stage
• All are winged as adults.
• Naiads are aquatic. Adults are found flying
near water.

Ephemeroptera = “Short Lived Wings”
Adult Characteristics
• Mayflies
• Adults are short lived (Vestigial
mouthparts)
• Nymphs are call ‘naiads’.
Penultimate nymphs are called
‘subimagos’
• Fragile bodies. Weak legs. Body
curved upward at the head and
tip of the abdemen, when at rest.
• Three caudal filaments at the end
of the abdomen.
• Adult swarms can be a nuisance

Ephemeroptera = “Short Lived Wings”
Naiad Characteristics
• Naiads emerge as adults in large swarms,
for a short mating period.
• Naiad antennae are short, bristle-like.
• Naids live 1-2 years in the water, with
many (30+) molts.
• 7 pair of abdominal gills.

Odonata = ‘tooth wing’
Adult Characteristics
• Dragonflies and
damselflies
• Adults have 2 pair of
membraneous, elongate
wings, with many
crossveins.
• Chewing mouthparts.
• Dragonflies hold wings
horizontal, at rest.
Damselfly wings are folded
over abdomen, upright,
when at rest.
• Long, thin abdomen.
• Adults patrol over streams,
ponds, an dother aquatic
habitats.
• All are predaceous.

Odonata = ‘tooth wing’
Naiad Characteristics
• Highly modified and hinged labium
– Highly predaceous.
• Dragonflies have rectal gills.
• Damselflies have tracheal gills.

Hemimetabolous Insects
• Hemimetabolous Development
• Most are winged
– Those without wings represent a secondary
loss of wings (e.g. aphids, scales

Orthoptera = ‘Straight wing’
Grasshoppers, katydids, crickets
• Two pair of wings. First
pair is a leathery
tegmina. Second pair is
membraneous and
fanlike.
• Chewing mouthparts.
• Can be found in a
variety of habitats – old
fields, woodland,
households
• Some are extremely
destructive pests to
cultivated crops

Dermaptera = “Skin Wing”
s
Earwigs
• Two pairs of wings
– Forewings short, square and veinles
• Leathery tegmina
– Hindwings fanlike
• Hemimetabolous Development
• Biting mouthparts
– Scavenge plant and animal matter
• Distinct Characteristics
– Cerci form pincers
• Color
– Pale brown to black,
– Temporarily white and cream after moulting
• Abdomen is uncovered and very flexible
• Distribution
– 1,800 species
– World-wide
– Ground dwelling, in crevices
Cerci/Pincers
Flexible
Abdomen
Leathery
Forewing

Isoptera = ‘Same Wing’
Termites
• Two pair of wings. Few cross
veins. Wings longer than body.
• Eusocial.
– Reproductive division of labor.
Castes. Cooperative care of young.
• Only reproductive caste has
wings, and only near the time of
nuptial flight.
• Live in ground or in wood.
• Many are pests of buildings. Most
are beneficial, because they
recycle nutrients from dead trees
and other plant materials.

Plecoptera = ‘Folded wing’
Stoneflies
• Two pair of wings. Both
membraneous. Hind pair folds fan
like under front wings.
– Wings folded flat over
abdomen
• Chewing mouthparts (reduced in
some species)
• Long, slender antennae
• Adults and naiads have 2 cerci at
apex of abdomen
• Adults on vegetation near water.
Naiads prefer cold, well-
oxygenated, water habitats.
• Naiads are an important prey and
predator component of aquatic
food chains.

Thysanoptera = ‘fringe wings’
• 2 pairs of tiny, feather-like wings
• Small  0.5 - 15mm long
• Mouthparts adapted for piercing and are highly
asymmetric
• Color: Y ellow, brown or black
• Very narrow body
• Prominent compound eyes
Adult Thrips Adult Thrips
Fringe Wings

Hemiptera = ‘Half Wing’
• 2 pairs of wings (some species wingless)
– Forewings generally hardened to some extent
• 1mm - 100mm long
• Mouthparts suctorial and developed for piercing
– Cibarial pump
– Most vegetarian or omnivorous.
– Some strictly carnivorous species
• Most are terrestrial, plant feeders (or
omnivores). A few families are aquatic. A few
families are predaceous.

Suborder Heteroptera
• Two sets of wings: Wings folded flat over the body at rest
– Forewings divided into two regions of different textures
– Hindwings membraneous and held under forewings, at rest
• Scutellum (triangle) on thorax
• Head projects horizontally and is visible from above
– Piercing/Sucking Mouthparts
Leathery part of forewing Membraneous part of forewing
Scutellum
Leathery part of forewing
Scutellum

• Two sets of wings
– Forewings are of uniform texture (all membraneous or leathery)
– Hindwings are membraneous
– Wings are held like a roof over the back
• Head deflected backwards
– Piercing/Sucking Mouthparts
Suborder Homoptera

Psocoptera
Book and Bark Lice
• Wings present or absent.
• If, present, 2 pair of
membraneous wings, with
reduced veination.
• Forewing larger than hindwing,
and held roof like over body at
rest.
• Small (<5mm in length)
• Enlarged face.
• Some species are pests that
damage books (feed on starchy
bindings).

Mallophaga / Anoplura
Chewing and Sucking Lice
• Mallophaga = chewing
mouthparts
– Head wider than thorax
– Many are important pests of
livestock
• Anoplura = sucking mouthparts
– Head is usually narrower than
thorax
– Includes species that are parasitic
to humans
• Minute (<4mm in length)
• Body dorso-ventrally flattened
• Tarsal claws

Holometabolous Insects
• Holometabolous Development
• Most are winged
– Those without wings represent a secondary
loss of wings (e.g. velvet ants, ants)

Coleoptera = “sheath wing”
• Two pairs of wings
– Forewings (elytra) are veinless, toughened and horny, covering the entire
abdomen and meeting at the midline
– Hindwings are membranous
• Prothorax is large, and covered by the pronotum
• Chewing mouthparts
• Distribution
– More than 300,000 species
– World-wide
– Habitats: from deserts to tropical regions, mainly ground dwelling and in
vegetation, some aquatic
– Feed on most solids, including crops, timber, pepper and dry bone

Neuroptera = ‘Nerve Wing’
Antlions, Owlflies, Lacewings
• Two pairs of membranous wings
– Dense network of cross veins on wings
– Prominent vein forks at wing margins
• Holometabolous Development
– Predators of smaller insects and pollen-eaters
• Distribution
– 6,000 species
– World-wide, although families are more restricted
– Vegetation, ground debris, in woodlands, sandy soils
Antlion Larva
Antlion Larval Pits Antlion Adult
Cross Veins on Forewings
Chewing Mouthparts

Megaloptera = ‘Big Wing’
Alderflies and Dobson flies
– Many veins and cross veins (forming a
nerve network)
– Numerous cross veins between costa
and subcosta veins
– Hindwing a bit wider at base than
forewing
– Anal area of hindwing folded fanlike at
rest
• Prognathous head with large
mandibles (sexually dimorphic)
• Larvae (i.e. hellgrammites) with
abdominal tracheal gills and anal
prolegs
• Larvae of Dobsonflies are often
used as fish bait.

Raphidioptera
Snakeflies
– Many veins and cross veins (forming a nerve network)
– Numerous cross veins between costa and subcosta veins
– Forewing contains a sitgma
• Prothorax elongate
• Front legs rise from the posterior end of the prothorax, and are
similar to other legs (not raptorial)

Lepidoptera = ‘Scale Wing’
– Both pairs covered in minute scales of various colours
• Mouthparts mainly suctorial, with proboscis
– Feed on liquids, usually nectar.
– Mud-puddling behavior
– Some drink tears, urine, and even blood
• Holometabolous
• Distribution
– 20,000 species
– Associated with higher plants, especially angiosperms
Mud Puddling
Nectaring

Siphonaptera = ‘No Wing’
Fleas
• Wingless
• Piercing, sucking mouthparts
– (obligate blood feeders)
• Laterally flattened
• Hindlegs adapted for jumping
• Pro-notal comb
• Larvae worm-like

Hymenoptera = ‘Membraneous Wing’
– Hind wings much smaller than forewings
• Biting mouthparts (except bees)
– Predators, herbivores and nectar feeders
• Distribution
– Over 100,000 species
– Habitats: from woodland to desert
• Social Systems in Hymenoptera
– Create own nests
– Young are provisioned to varying degrees by parents / other
adults

• Suborder Symphyta
– No typical wasp-waist
– Hold wings flat over the body

• Suborder Apocrita
– Wasp waist
– Have wingless castes
– Divided into two groups, the Parasitica and
Aculeata (Social wasps)

Diptera = ‘two wings’
• One pair of wings
– Membranous forewings used for flight
– Hindwings form small stick-like halteres
• Suctorial mouthparts
• No cerci on the abdomen
• Distribution
– Mainly associated with flowers and decaying organic matter
– Feed on vegetation and organic matter, some blood feeders and ectoparasites,
some species do not feed at all as adults
– Over 100,000 species,

• Suborder Nematocera
• Small, delicate insects
• Slender, many segmented antennae, with
no arista
• No distal cell in the wing, open anal cell
widens towards the wing margin
• Larvae have prominent, biting jaws

• Suborder brachycera
• Stout flies
• Antennae 3-segmented, shorter than the
thorax, may have terminal arista
• Discal cell not always present
• Larvae have reduced jaws which can be
retracted into the head

• Suborder Cyclorrapha
• Stout flies
• Antennae non-prominent, 3 segmented
and pendulous, bristle from dorsal surface
• Circular seam on head
• Larvae are maggot-like, with no visible
jaws

Module Objectives
• Part I
• Part II
• Part III
• Part IV

Collecting Insects in Gardens
Baby Food Jars
Water Pan Traps

Impact of Polylectic Pollinators on
Ornamental Invasives
• Exotic plants are often less subject to
damage from insect herbivores
• Exotic plants are not discriminated
against by insect pollinators

Pitfall Traps

Light Traps

Nets and Vacuums

Date / Locality
Collecting Method or
Plant from which Insect was Collected
Determination Label
(Including who ID’d the specimen)
Pinning and Labelling
Where to Pin, by Order

Diagnosing Insect Problems
• Do not, if at all possible, diagnose a pest problem from a
photo
• Get a sample of the ‘insect’
• Get a sample of the damage
• Make sure that the organism is indeed an insect
• Is it an adult or a juvenile?
• Identify the insect to order (easier to do for adults than
for juveniles)
• What do the wings look like? Are they membraneous? Are there
2 pair? What about cross veins? Are the wings held flat over the
body, or tent like over the body?
• Do the mouthparts of the insect match up with the type of
damage being reported?

Internal Feeders
Miners
Borers

External Feeding Guilds
Chewers Mesophyll Feeder

Closing Remarks
• Insects are cool! Most are innocuous to
humans. Many are beneficial. Relatively
few are pests (but these pests make their
presence known!).
• Work your way through a standard set of
questions, when ID’ing insects to order.

Entomology LECTURE2 (1).pptx

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Entomology LECTURE2 (1).pptx