Welcome to the Wonderful World of Insects

Welcome to the
Wonderful World of
Insects
Characteristics of Insects
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A body divided into three parts: head, thorax & abdomen
Three pair of legs
Usually one pair of antennae
Usually one pair of compound eyes
Usually two pair of wings
Chitinous exoskeleton
Beetles (Coleoptera)
More than
350,000 Species Worldwide
•  Front pair of wings = elytra
•  Hind pair are membranous
•  Chewing mouthparts
Butterflies & Moths
Butterflies & Moths (Lepidoptera)
More than 165,000 Species
Worldwide
•  Wings have scales
•  Siphoning mouthparts
Flies (Diptera)
Flies (Diptera)
More than150,000
Species
Worldwide
•  Hind pair of wings = halteres
•  Variable mouthparts
1/6 of the
world’s human
population is
affected by a
fly-borne illness
at any one
time.
Wasps, Bees & Ants
Wasps, Bees & Ants
(Hymenoptera)
More than 130,000
Species Worldwide
•  Front & hind pair of wings
connected via hamuli
•  Many capable of stinging
•  Many social
True Bugs (Hemiptera)
True Bugs (Hemiptera)
More than 82,000
Species
Worldwide
•  Piercing-sucking mouthparts
•  Have leathery/half
membranous wings
Vertebrate Skeleton
Purpose
1. 
2. 
3. 
4. 
5. 
Provide a framework for all body
systems and give the body
adaptive form.
Provide attachments for muscles.
Enclose and protect vital organs.
Serve as a reserve storehouse for
minerals.
Enclosing armor (protection).
Membranes
vs. Sclerites
Metamorphosis
Instar – the insect between successive molts
Three major types of metamorphosis in insects:
I. 
Add an abdominal segment with each molt
II.  Little change in appearance until final molt
(simple metamorphosis)
III.  Immature stages differ radically (complete
metamorphosis)
II. Simple Metamorphosis
(little change)
a.  Ametabolous – without change.
b.  Paurometabolous – both immatures and
adults are in the same habitat.
c.  Hemimetabolous – immature stages are
aquatic and adults are terrestrial.
Ametabolous
•  Springtails
•  Diplurans
•  Jumping Bristle-tails
•  Silverfish
Paurometabolous
(nymphs)
nymphs
Hemimetabolous
(nymphs or naiads)
Complete Metamorphosis
(Holometabolous)
“Entognatha”
Apterygota Insecta
(Microcoryphia)
(Thysanura)
Pterygota
“Palaeoptera”
“Neoptera”
Exopterygota
Endopterygota
From: An
Inordinate
Fondness for
Beetles
Insect Vision
•  Ocellus – simple eye,
lacking crystalline lens
•  Stemmata – simple
eye, with crystalline
lens; found laterally on
holometabolous larvae
•  Ommatidium – single unit or component of
compound eyes; has crystalline lens and light
concentrating cells
•  Compound Eye – aggregation of ommatidia
We have two eyes that face
forward and have good
resolution, providing a
detailed image, but a narrow
field of view. Our eyes
detect a fairly broad range of
color and give us good
depth perception. However,
we cannot see into the
infrared or ultraviolet ends of
the spectrum as some
insects can.
Butterfly Vision
•  Butterflies can see
more colors than any
other animal on Earth!
•  Can see ultraviolet
•  Many flowers have UV
lines or patterns to
guide pollinators
•  250º field of view
Caterpillar Vision
•  up to 6 pairs of simple eyes
•  distinguish dark from light
•  would be consider legally blind
Dragonfly Vision
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Almost 360º field of view
Sharpest image up close
Don’t perceive shades of red
Up to 30,000 lenses in each eye
Jumping Spider
Vision
•  have very large eyes
•  see far more clearly than
insects
•  no compound eyes, but up
to eight simple eyes that
work more like ours
•  4 largest eyes face forward
and give them focused and
colorful images within a
fairly narrow field of view
•  secondary eyes on side and
top of head add to field of
view, but can’t focus well or
see color
Variations
in the
compound
eye
250 nm
600 nm
The Basic Antenna
(filiform)
pedicel
scape
flagellum
Antennal
Variation
filiform moniliform
serrate
capitate capitate/
clavate
pectinate bipectinate
stylate
lamellate
plumose
setaceous
aristate
geniculate
Insect
Mouthparts
Hemiptera Mouthparts
Insect Leg
femur
tibia
pretarsus
tarsus
coxa
trochanter
Raptorial
Legs
Mantidae
Mantispidae
Saltatorial
Legs
Acrididae
Rhaphidophoridae
Dytiscidae
Corixidae
Natatorial
Legs
Dytiscidae
Primitively
Wingless
(Apterous)
Thysanura/Zygentoma
Microcoryphia/Archaeognatha
Odonata
Ephemeroptera
Palaeopterous
Neopterous
Plecoptera
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