Insect morphology insect morphology insect morphology

Here u will learn about insect morphology

1. Insect Morphology
Dr. Farrukh Baig
Entomology
MNS-University of Agriculture, Multan

2. Outline
1. Integument
2. Head
Types of Antennae
Eyes and Types
Mouthparts and Types
3. Thorax
Legs and Types
Wings and Types
4. Abdomen
Segmentation
Body Systems

3. External Morphology (grasshopper)
Head Thorax Abdomen
Antenna Compound eye Wing

4. The integument consists of three main layers.
1. Cuticle (Epicuticle, Exocuticle and Endocuticle)
2. Epidermis
3. Basement membrane
What is integument ?
The outer covering or body wall of an insect is called
integument

5. Integument
Cross-section of cockroach cuticle Integument cross-section

6. 0








TTYYPPIICCAALL IINNSSEECCTT IINNTTEEGGUUMMEENNTT

SETA OR HAIR
SOCKET

FIXED HAIR

EPICUTICLE

EXOCUTICLE



PORE CANAL

ENDOCUTICLE


DUCT OF GLAND




EPIDERMIS

BASEMENT
MEMBRANE

GLAND
TRICHOGEN
TORMOGEN

7. Cuticle
➢Outer non-cellular layer.
➢Itissecretedbytheepidermalcellsbelowit.
➢Whennewlyformeditisflexibleandelastic
➢Lateronitbecomeshardthroughtheprocessofsclerotization.
➢Itprotectstheinsectsfromwaterloss,penetrationofinsecticides
andprovidesgroundfortheattachmentofmuscles.

8. Epicuticle
It is the outermost non-chitinous and very thin layer.
It is 1-4 m in thickness.
It is comprised of cement, wax, lipoprotein, polyphenol wax and
cuticulin layers
Exocuticle
It is the middle much thicker layer.
It is hard, pigmented, darker
Consists of chitin and protein
Endocuticle
Itistheinnermostthickestlayer,
Itissoftandflexibleandalsocontainschitinandprotein.

9. Epidermis
➢Unicellularlayerofcellswhichisknownasepidermis.
➢Amongthenormalcellsofepidermisaresomemodifiedorspecializedcellsforperforming
differentfunctions.
➢Thetrichogenandtormogencellsparticipateintheformationofsetaeorhair,whiletheglandular
cellsthrowtheirsecretionsthroughtheirductsonthesurfaceofcuticle.
➢Forformingaseta,asingletrichogencellbecomesgreatlyenlarged.Anotheradjoiningcellor
tormogenisalsoenlargedtoformacup-likesocketorpitandanarticularmembraneofthehairat
itsbase
Basement membrane
➢Itisaverythin(upto0.5mthick)
➢Non-cellularlayerlyingbeneaththeepidermis.
➢Theepidermalcellsstandonit.

10. Setae
Commonly known as hairs
Arise from a cup like Pit
At the point of articulation a membrane is present
Cuticular Processes
Rigidly connected with the cuticle
At the point of articulation a membrane is absent
Cuticular Appendages
1. Setae
2. Cuticular Processes

11. What is exoskeleton ?
The body wall having muscles on its inner side is called
exoskeleton.
Major component of exoskeleton
Chitin –25 –50% dry weight –mostly polysaccharide
Major Proteins
A –Sclerotins
B –Arthropodins
C –Resilin

12. Exoskeleton Hardening
➢Newly molted exoskeletons are soft and light colored.
➢Exposure to air and other chemicals(tyrosine) produced
by insect causes hardening.
➢Sclerotization (hardening) and later melanisation
(browning) takes place.
➢This can take several days

13. Exoskeleton Advantages
1. Support and strengthen the body of insects.
2. Protection of insects, especially the internal organs.
3. Protection against physical damage and abrasion
4. Provides excellent protection against many predators
5. Help for attachment of muscles
6. Retardation of water movement
7. Barrier against pesticides absorption

14. 1. For exoskeleton it is more difficult to regulate body temperature
2. Major restriction on growth
3. Exoskeleton is the thicker and heavier
4. Once damaged the internal organisms of an exoskeleton are very
susceptible
Exoskeleton Disadvantages

15. How Insects Jump Out of Their Exoskeleton
➢Chitinases and proteases secreted from endodermal glands dissolve endocuticle
➢Epidermal cells multiply and secrete new cuticle
➢Waxy layer is also secreted
➢Old insects cuticle splits along specialized wrinkles (ecdysiallines) and insect crawls out

16. Apodemes
Cuticularingrowthsorfourdeepinvaginationsthatmeetinternally
andformabracefortheheadandmusclesattachmentandfoundin
allinsects.
Inthepterygoteinsects,however,theseingrowthsstartatthe
tentorialpitsonthefaceandhaveevolvedtoformthehead
endoskeletonortentorium.

17. Fourmajorapodemesprovidesupportto
aninternalized‘endoskeleton’
Tissuesupportandattachmentsites.
For muscles.
•Tentorium---------head
•Furca---------------thorax
•Phragma----------thorax
•Apophysis--------thorax

18. Sulcus
These sclerites are separated by the grooves called sulci (sing. sulcus)
Appendages
Therearemanyoutgrowthsofthebodywall(suchasantennae,legs,wings,etc.)whichare
calledappendages
Sclerites
The body wall consists of a number of hardened areas or plates, the sclerites

19. Coloration
Pigmentary or chemical colours
Somesubstancesofdefinitechemicalcompositionwhichhavethepropertyof
absorbingsomelightwavesandofreflectingother.
Cuticularcolours:
Mostlycontainedintheexocuticle.Thesearebrown,blackandyellow,whichare
permanent.
Epidermalcolours
Intheformofgranulesordropsoffatinthecellsoftheepidermis.Theymaybered,
orange,greenoryellow
Subepidermalcolours:
Containedinthefatbodyandblood.

20. Appendages of Head

21. Antennae
Structure of typical Antenna
•Each antenna consist of three parts:
1. Scape
2. Pedicel
3. Flagellum
•Paired, jointed primarily sensory appendages
•Located b/w or below the compound eyes on the head
•Also called feelers
•Absent in order Protura

22. •Selection of food
•Selection of plants for the purpose of egg laying
•Find out friend and foe (Communication)
•Feelers
Function of Antennae

23. Appendages of insect Head
Antennae
•Sensory organs
•One Pair on head
•Jointed
•Called “feelers”
•Filiform most common
•shape (segments =
size)
•May be modified

24. Modifications of Antennae
Moniliform
•They are bead like in shape
•Example-termites

25. Modifications of Antennae
Filiform
•They have thread like shape
•Example-ground beetles, Cockroaches

26. Modifications of Antennae
Clavate
•Gradually clubbed at the end
•Example-carionbeetles

27. Modifications of Antennae
Setaceous
•These are simplest type of antenna
having bristle shape
•They are found in dragon fly, Cicadas

28. Modifications of Antennae
Geniculate
•They are hinged or bent like an elbow
•Example-bees and ants, weevils

29. Modifications of Antennae
Aristate
•Pouch like with a lateral bristle.
•Example-house fly

30. Modifications of Antennae
Plumose
•These type of antenna have horizontal brushes on root antenna
•They are found in mosquito

31. Plumose
Modifications of Antennae

32. Modifications of Antennae
Flabelate Antennae

33. Pectinate
•Comb like shape
•Example-glow worm and fire colored beetles
Modifications of Antennae

34. •Bi-pectinate
Modifications of Antennae

35. Serrate
•They are saw toothed
shape
•Example-click beetles
Modifications of Antennae

36. •Capitate antenna
•Abruptly clubbed at the end.
•Example-butterfly
Modifications of Antennae

37. Appendages of Head-EYES
Simple eyes, Ocelli(1 to 3)
•Records daily changes in light intensity

38. •Compound Eyes
➢Numerous faucets that each have a lens, each singly functional
➢Senses color, movement, and, to a lesser extent, distance
Appendages of Head-EYES

39. •Compound Eyes
Appendages of Head-EYES

40. Appendages of Head-Mouthparts

41. •MouthpartsAnother prominent feature of the head
•Adults that don’t feed
•Vestigial –highly reduced
•Absent –not there
•Shape and morphology related to the food it consumes
Appendages of Head-Mouthparts

42. Orientation of head (Three types)
1. Hypognathous
2. Prognathous
3. Opisthognathous
Six segments of head
1.Pre-antennary
2. Antennary
3. Intercalary
4. Mandibular
5. Maxillary
6. Labial

43. Hypognathous:
Thistypeofheadhavingthemouthpartsonitslowersideandprojecting
downwardiscalledhypognathous

44. Prognathous:
Head in which the mouthparts are on the front side and project forward is
called prognathous

45. Opisthognathous:
Typeofheadinwiththemouthpartsonitslowersideintheformofa
proboscisprojectingbackward

46. OpistognathousPrognathous Hypognathous

47. Types of Mouthparts
❑Chewing
•Ex. Grasshopper or mantis
❑Piercing-sucking
•Ex. Mosquito or assassin bug
❑Sponging
•Ex. House fly
❑Siphoning
•Ex. Flea
❑Chewing-lapping
•Ex. Honey bee
Appendages of Head-Mouthparts

48. Chewing Mouthparts
•Clypus–immovable; above the
labrum
•Labrum –“upper-lip”; can be
bent
•Mandibles –paired; responsible
for tearing or biting food and
then grinding or chewing it so
insect can ingest; darkest portion
is the hardest
Appendages of Head-Mouthparts

49. Chewing mouthparts
•Maxilla –below mandible;
projection near base called
maxillary palpiwhich helps
move food into the mouth;
•Labium –“lower-lip”
•Labial palpi–similar function
to maxillary palpi; project from
base of labium
•Hypopharynx–“tongue”; on
upper surface of labium
Appendages of Head-Mouthparts

50. Piercing-sucking mouthparts
•Why?
•Liquid diet
•Type of liquid diets?
•Nectar
•Plant juices
•Blood
•Mouthparts as a whole called
beak
Appendages of Head-Mouthparts

51. Piercing-sucking mouthparts
•Same general mouthparts as
chewing, but shaped differently
•Mandibles and maxillae are
shaped into long, slender stylets
•The styletsare housed within a
protective sheath made from the
labium
Appendages of Head-Mouthparts

53. Piercing-sucking mouthparts
•One or more channels
•Suck in food
•Salivary channel for secretions
•Types of secretions
•Antiesthetic
•Anti-coagluants
•Toxins
•Enzymes (break down food)
Appendages of Head-Mouthparts

54. Sponging Mouthparts
•Why?
•Non-invasive sucking of liquids
•Types of meals?
•Exposed food or liquid
•Blood
•Common among flies
Appendages of Head-Mouthparts

55. Sponging Mouthparts
•The proboscis is a
modified labium
•The end of the
proboscis are the
modified labella
•The labella are fleshy
lobes with transverse
grooves that use
capillary action to draw
food up to the mouth
Appendages of Head-Mouthparts

56. Variations of sponging mouthparts
•Horse fly –have blade-like part
that slices skin. Blood pools and
sponging mouthparts sponge the
blood up.
Appendages of Head-Mouthparts

57. Variations of sponging mouthparts
•Tsetse fly –have teeth on labella
that cut the skin then they suck up
the blood
Appendages of Head-Mouthparts

58. Siphoning mouthparts
•Why?
•Get liquid meals from deep within
flowers
•Types of food?
•Nectar
•Water
•Salt and minerals in liquid
•Butterflies and moths
Appendages of Head-Mouthparts

59. Siphoning mouthparts
•Coiled tongue is modified
maxillae
•Labial palpiare located
between head and proboscis
•Other mouthparts are either
too small to see or have been
lost evolutionarily
•Proboscis works like a straw
Appendages of Head-Mouthparts

60. Chewing Lapping mouthparts
•Insects that lap up liquids, but
still have intact mandibles
•Uses mandibles to perform
other tasks
•Ex. Honeybee will use
mandibles to form wax into
combs
Appendages of Head-Mouthparts

61. •Chewing Lapping mouthparts
Appendages of Head-Mouthparts

62. Other mouthparts
•Antlionlarvae have huge toothed mandibles
that grab ants as they fall into their sand
traps
•Dragonfly larvae (naiads) labiumshave
become a long, flat hinged structure that
shoots out and impales or hooks the prey
•Antlionlarvae
•Dragonfly larvae
Appendages of Head-Mouthparts

63. Insect Thorax
-3 segmented
ProthoraxMesothoraxMetathorax
Pterothorax
Anterior
Posterior

66. pleuron
notum
sternum
pleuron
Cross section of insect thorax
Insect Thorax

67. pleuron
notum
sternum
scutum
scutellum
epimeron
basisternum
trochantin
sternellum
tergum
episternum
Insect Thorax

68. pleuron
notum
sternum
Insect Thorax

69. Internal support in thorax
pleural ridge
pleural apophysis
sternal apophysis
sternopleural muscle
furca
Furca
Pleural/sternal apophysis
Apodemes
Insect Thorax

70. Appendages -Legs
coxa
trochanter
femur
tibia
tarsus
pretarsus
tarsomeres
coxa
Insect Thorax

71. •11 Segments of Legs
1.Epicoxa (present, e.g., as the wing articulation on the
thorax of winged insects)
2.Subcoxa (embedded in pleu-ral membrane as the pleuron)
3.Coxa
4.Trochanter
5.Prefemur (typically fused either with the trochanter or
femur)
6.Femur
7.Patella (fused with the tibia)
8.Tibia
9.Basitarsus
10.Eutarsus (often subdivided)
11.Pretar-sus
Insect Thorax
Appendages -Legs

72. Insect Leg -Articulation
Monocondylic
leg
•Monocondylicjointshaveasinglepointofarticulation,somewhatlike
aball-and-socketjoint,andusuallyaresituateddorsally.
•Theyallowconsiderablefreedomofmovementandarecharacteristic
ofthelegsoflarvalinsects
Insect Thorax

73. Insect Leg -Articulation
Dicondylic
leg
Insect Thorax
•Dicondylic joints have an anterior and a posterior condyle, or a dorsal
and ventral condyle in the case of the trochanterofemoral joint.
•They typically limit movement to that of a hinge.

74. Insect Leg -Articulation
Monocondylic
Decreasing mobility
Increasing strength
Trochantin Dicondylic
leg leg leg
Insect Thorax

75. Modifications of insect legs
•Saltatorial (metaleg of AK grasshopper)
•Cursoroial (metaleg of cockroaches)
•Antenna cleaner (proleg of Honeybee)
•Pollen colleting (metaleg of honey bee)
•Tarsal structures (Rubber fly)
•Silk secreting (proleg of webspinner)
•Clinging (louse)
•Natatorial (metaleg of giant water bug)
•Fossorial (pro leg of mole cricket)
•Raptorial (proleg of mentid)
Insect Thorax

76. Saltatorial (jumping)
Migratory locust (Orthoptera: Locustidae)
Insect Thorax
Thoracic Appendages –Legs Modifications

77. Insect Thorax
Thoracic Appendages –Legs Modifications
Antenna Cleaner Legs (Pro legs of Honey bees)

78. Insect Thorax
Thoracic Appendages –Legs Modifications
Pollen collecting Legs (Meta legs of Honey bees)

79. Insect Thorax
Thoracic Appendages –Legs Modifications
Clinging Legs (Louse)

80. Insect Thorax
Thoracic Appendages –Legs Modifications
Silk Secreting (Pro-leg of Webspiner )

81. Insect Thorax
Thoracic Appendages –Legs Modifications
Cursorial (running) Tiger beetle, Cockroaches

82. Thoracic Appendages –Legs Modifications
Digging (Fossorial)
Mole cricket (Orthoptera:Gryllotalpidae)
Insect Thorax

83. Insect Thorax
Thoracic Appendages –Legs Modifications
Natorial (swimming) Predaceous diving beetle

84. Pneustonic (water surface)
Whirlig beetle (Coleoptera: Gyrinidae)
Insect Thorax
Thoracic Appendages –Legs Modifications

85. Raptorial (Apposition/Grasping)
Insect Thorax

86. Suction (mating pads)
Predaceous diving beetle (Coleoptera:Dytiscidae)
Insect Thorax
Thoracic Appendages –Legs Modifications

87. Thoracic Appendages -Wings
Development
cuticle
haemocoel
Evagination of body wall
1.
2.
blood(hemolymph)
tracheanerve
cuticle
epidermis
vein

88. The Insect Wing
costa
subcosta
radius
medial
cubitus
anal
jugal
C
Sc
R
RS
MA
MP
CuA
CuP
A
J

89. The Insect Wing
Wing modifications
Dragonfly (Odonata)
-archedictyon

90. Evolutionary Trends
1. Reduce number of cross veins = loss of weight
2. Fuse or lose longitudinal veins
3. Less sclerotization
4. Reduce fluting except on anterior

91. The Insect Wing
Wing folding

92. The Insect Wing
Wing folding
Melolontha

93. Wing Coupling
Paleoptera

94. Wing Coupling
Frenate (Lepidoptera)
frenulum retinaculum
male
female

95. Wing Coupling
Hamate (Hymenoptera)
Hamuli (hooks)

96. Wing Coupling
Jugate (Lepidoptera)

97. Wing Coupling
Overlap (Lepidoptera)

98. The Insect Wing
Wing modifications
Elytra (Several Orders)
elytra

99. The Insect Wing
Wing modifications
Hemelytra (True Bugs -Hemiptera)

100. The Insect Wing
Wing modifications
Halteres

101. INSECT PHYSIOLOGY

102. INSECT DIGESTIVE SYSTEM

104. Generalized Diagram (typical of grasshopper)

105. Absorption of digested material

106. Insect Excretory System
Malpighian Tubules

107. INSECT CIRCULATORY SYSTEM

108. INSECT CIRCULATORY SYSTEM

109. Insect Respiratory System

110. Insect Respiratory System (to Draw)
Spiracles, Tracheae, Tracheal Trunks & Air Sacs, Tracheoles

111. Respiratory System in Aquatic insects
Siphon

112. Respiratory Position of different mosquitoes

113. Supra-oesophageal
ganglion
Sub-oesophageal
ganglion
INSECT NERVOUS SYSTEM
Ventral Nerve Cord

115. Insect Abdomen
Insect Nervous System

116. Insect Reproductive System

117. Vas efferens
Testicular follicles

118. Ovariole
Ovary

119. Types of Reproduction
1-Oviparity:-Grasshoppers, butterflies
2-Viviparity:-Aphids
3-Parthenogenesis:-Wasps, Thrips
4-Paedogenesis:-Cecidomyids & Midges
(Henriasp)
5-Polyembryony:-Parasitic wasps
6-Hermaphroditism:-Phorid flies, Scale
insect

120. Insect Abdomen
Insect Muscular System

121. Insect Abdomen
Insect Exoskeleton

122. Caterpillar Digestive System Milkweed Bug Digestive System
Insect Abdomen
Insect Digestive System