Transcript INTERNAL STRUCTURES OF INSECT

INTERNAL
STRUCTURES OF
INSECT
DIGESTIVE SYSTEM
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Related with i) digestion; ii) absorption; 3)
water balance; 4) excretion
Main division: 1) foregut
2) midgut
3) hindgut
FOREGUT
Mouth: mandibles break down food
to small pieces. inside mouth salivary
glands excrete enzymes to: 1) aid
breakdown of food; 1) add moisture
 Phariynx: region that is circled by
muscles – force food from mouth to
esophagus
 Esophagus: at tube-like connecting
the crop(tembolok)
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FOREGUT
Crop: storage area for food. Insect eats
beyond repletion, so need storage before
pushed into midgut
 Proventriculus: sometimes grinding organ
(with small teeth; sometimes only as a
valve between fore & midgut
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FOREGUT
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MOUTH  PHARYNX  ESOPHAGUS
ENZYMES FROM
SALIVARY GLANDS
CROP (TEMBOLOK)
PROVENTRICULUS
MIDGUT
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Ventriculus: Enzymes breakdown food
chemically, initiate nutrient uptake (absorption
amino acid, carbo, lipids, vit., mineral)
Single layer epithelial cells, convoluted
(berlingkar) & folded: provide absorption space
The lining is peritrophic membrane: 1) as a sieve
(penapis) which allows enzymes & b/down
poducts to move thru it. 2) protect midgut
Gastris caeca (sekum gastrik): involved in
harbouring m/organisms
Function of midgut??
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1)
2)
HINDGUT
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Water absorption and waste excretion
Waste products are concentrated and packaged
for excretion
Consists of 1) intestine (ileum+colon); 2)rectum;
3) anus
From intestine pass to rectal pads: further salt &
water retained
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Malphigian tubules: junction of mid & hindgut
 Function: kidneys of insect: absorbs salts,
water and wastes from the surrounding
hemolymph. The wastes then are released
from the organism in the form of solid
nitrogenous compounds.
Waste in form of uric acid (dry and nontoxic)
Feces Leaf chewing insects very distinctive –
take the shape of the intestine
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Function:
 1) filter hemolymph
 2) recover lost metabolites, water & salt
 3) excrete waste
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Ileumkolon  rectum rectum anus
(waste in form of acid uric- dry & nontoxic
T. Malphigian border of mid & hindgut
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Insect Nutrition
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Diverse
Some insects eat variety plants spp. Or maybe
restricted to single plant
Eg: Manduca sexta: eats Solanaceae (tobacco,
tomato,potatoes)
What do insects need?
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1)FAT (=LIPID)
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2) CARBOHYDRATE(SUGAR)
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For energy
3) PROTEINS
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For hormone production
Need amino acid, for development (eg arganine, leucine,
lysine etc)
4) Vitamins
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Vitamin A for vision
Vit B1 (thiamine:energy),B2
(riboflavin:energy),B6(pyridoxine:amino acid metabolism)
RESPIRATORY
SYSTEM(TRACHEAL SYS.)
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Gas exchange
Insect blood doesn’t contain haemoglobin
Has massive plumbing with tubes carry air to
cells
GAS (outside)spiracles tracheal trunk
(pimary trachea) 2o & 3o trachea tracheol
SPIRACLE
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Air comes thru
Opening on the body
Open and close (have muscles) to minimize
water loss
Mechanism:
Co2 high in body muscles relax  spricales open
Co2 escape + Oxygen in
 O2 in body approx. outside  muscles recover 
spricales pull shut
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TRACHEAL TRUNK
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Spiral of tough filaments (resist collapse)
Branches to secondary & tertiary trachea
Smaller tubes : tracheols
Tracheols are intimately associatied with cells
Eg: muscles cells: tracheols enter deep into the
cells: close to mitchondria (where o2 needed)
Or diffuses from tracheols to cells, Co2 from
tissues to tracheols
AQUATIC ADAPTATION
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Some without spiracles, they have modified gills
The gills with thin layer of cuticles with lots of
tracheoles
Some have ‘snorkel’ : a tube with spiracles- the
tube above water for air intake
CIRCULATORY SYSTEM
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No arteries, veins or capillaries
The organ sits in open cavity filled with insect
blood called ‘HEMOLYMPH’
FUNCTIONS
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Transport of nutrient and hormones
Storage for substance like acid amino
Water reservoir
Hydrostatic pressure for movement
Protection from foreign organism which invade
HEMOLYMPH
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Consists of:
 1) 90% PLASMA:
 a watery fluid: usually clear, sometimes greenish or
yellowish
 high concentrations of amino acids, proteins, sugars, and
inorganic ions.
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1) 10% HEMOCYTES:
 various cell types
 involved in the clotting reaction, phagocytosis, and/or
encapsulation of foreign bodies.
does NOT contain hemoglobin (or red blood cells).
Oxygen is delivered by the tracheal system, not the circulatory
system.
DORSAL VESSELS (SALUR DARAH)
AORTA
•In front of the heart,
•lacks valves or muscle.
•continues forward to the head
and empties near the brain.
•Hemolymph bathes the organs
and muscles of the head as it
emerges from the aorta
•then back over the alimentary
canal,through the body until it
reaches the abdomen and reenters the heart.
HEART
•divided segmentally into
chambers
• that are separated by valves
(ostia) to ensure one-way flow of
hemolymph.
•A pair of alary muscles are
attached laterally to the walls of
each chamber.
•Peristalsis: these muscles force
the hemolymph forward from
chamber to chamber
PERICARDIAL
SINUS
DORSAL DIAPHRAGM
PERIVISCERAL
SINUS
PERINEURAL
SINUS
VENTRAL DIAPHRAGM
To facilitate circulation of hemolymph, the body
cavity is divided into three compartments:
REMEMBER!!!!
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NOT CARRY OXYGEN!!!
 So blood flow is not critical like us
human
HEMOLYMPH FROM BODYENTER OSTIA( HEART MUSCLE RELAXPERISTALSIS
BATHES HEAD
AND ALL ORGANS
& BACK TO
ABDOMEN
AORTA
(LACK MUSCLES & VALVE)
MOVE FORWARD CHAMBERS
SENSORY SYSTEM
 Exoskeleton
need sensory organ
 To evaluate changes in the
environment
 First info receive by SENSILLA:
specialized cuticullar structure
equipped with nerve cells and neuron
 Usually hair-like
PHOTORECEPTOR
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Light/vision
Vision can be restricted in insects
Some to differentiate light from dark
Some can distingusih shape & images
3 types of photoreceptor:
1) ocelli
 2)stemmata
 3) compound eye
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OCELLI
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Many adults and nymph of hemimetabolous
Related to flight, most flightless insects don’t
have
Sensitive to light intensity
Cannot perceive images or shape
STEMMATA
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Only on larvae of holometabolous
Larvae of holometabolous almost never have
compound eyes
capable only of detecting light.
cannot focus or allow reception of images.
COMPOUND EYES
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Consists of numerous hexagon shaped
facets/lense called ommatidium
2 major components: 1) lenses; 2) light receiving
syst.
MECHANISM
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Lens guide light to a group of pencil-shaped like
cells tie up together called rhabdom
These photoreceptor absorp the light then
convert to eletrical signal which is conveyed in
brain
RHODOPSIN: chemical pigment to absorb
light, with the help of Vitamin A
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Insect eyes cannot focus until sharp image
The best insect eye resolves less detail than
human eye
But sensitive in movement
So what they perceive ? Shape & form
Broken shapes are differentiated solid
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Some can see colours
Pigments in ommatidia sensitive to different
array of colours
Insect sees from 700 nm (red) range down to
3o0 (violet)
Bees see flower blue
CHEMORECEPTOR
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Smell/taste (olfaction)
Well developed compared to photoreceptor
A) Close range,
chemical signals in solution form (taste)
 Found in legs
 Eg: honeybee: taste sweet, sour, salty and bitter
 Eg: red admiral butterfly 200x sensitive to sugar than
hman tongue
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CHEMORECEPTOR
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B) distant range (jarak jauh)
Airborne chemical signal = smell
 Found on antennae
 detect odours great distance, miles
 Useful for finding mates
 PHEROMONES: chemical signals
 Smells much more sensitive than human
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MECHANORECEPTOR
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Touch/pressure/vibration or sound
Sense of pressure/touch usually on legs: often
contact to ground
Many insects are deaf: sound not really
important
Tympanum: on legs for cricket, on abdomen for
cicadas
Hair sensilla in antenna: eg Johnston’s organ
THERMORECEPTOR
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Changes in temperature
Bed bug use thermoreceptor to locate warm
blooded verteb.
HYGRORECEPTOR
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changes of humidity
Blood feeding parasites
 Warm, moist breath good indicator of host
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NERVOUS SYSTEM
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INSECT SIMPLE CREATURE????
What happen when you attack the fly?????
3 components
1)brain
central
 2)ventral nerve cord
nervous system (CNS)
 3)peripheral nervous system (extend outside the
central nervos system to serve the limbs and organs
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Each of the components consists millions of
neurons
VENTRAL NERVE CORD
WHAT IS NEURON?
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Nerve cell
For information transfer
Composed of
1) dendrite (enter the cell body)
 2) cell body (nucleus found)
 3) axon( leaving the body)
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Repeating unit of neuron form a nervous system
Individual nerve cells connect with one another
through special junctions, called synapses.
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3 categories, depending on their function within the
nervous system:
 1) Afferent (sensory) neurons
 bipolar or multipolar cells
 dendrites associated with sense organs or receptors.
 carry information toward the central nervous system.
A
D
2) Efferent (motor) neurons
 unipolar cells
 conduct signals away from the
central nervous system
 stimulate responses in muscles
and glands.
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A
D
3) Interneurons
 unipolar cells (often with several collaterals
and/or branching axons) that conduct
signals within the central nervous system.
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BRAIN
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Nerve cord to the head is the BRAIN
3 pairs of ganglia region:
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1)protocerebrum: associated with vision; they
innervate the compound eyes and ocelli.
2)deotocerebrum: pair lobes with sensory pathway to
antennae
 3)tritocerebrum: lobes with connective to 1st
ganglion of ventral nerve cord
VENTRAL NERVE CORD
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1) subesophageal ganglion
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2) thoracic ganglia
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innervates mandibles, maxillae, and labium,
hypopharynx, salivary glands, and neck muscles.
) control locomotion by innervating the legs and
wings.
3) abdominal ganglia
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control movements of abdominal muscles.
PERIPHERAL NERVOUS
SYSTEM
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1) neuron of sensory organs (sensory neuron)
2) neuron attached to muscles (motor neuron)
Function of insect nervous syst critical in insect
control
REPRODUCTIVE SYSTEM
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Reproduce: 1) SEXUALLY 2) ASEXUALLY
Mosy sexually
2 sex cells
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1) sperm
2) ovum
MALE REPRODUCTIVE SYSTEM
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Sperm produce by testes (A)
From testes sperm stored in
seminal vesicle (B)
During copulation discharge
thru aedeagus (C) (penis) along with
secretion from accessory glands (D)
A
D
B
C
FEMALE REPRODUCTIVE
SYSTEM
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Ovum produce by OVARY (A)
Inside ovaries: OVARIOLES (B)
A
egg producing tubules
SPERMATHECA (C): storing sperm
-sp. That mate once stored sperm
for months/years
ACCESSORY GLANDS (D): provide
materials for egg to attach to substrate
B
D
C
ASEXUAL REPRODUCTION
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Benefit:
 Rapid increase in number
 Close match between organism & environment
 Save time: don’t have ti find and court mate
Disadvantage: offspring (anak) not variable
3 modes(cara):
 1) HERMAPHRODISM: egg & sperm produce by same
individual
 2) GYNOGENESIS: egg is activated by the presence of
sperm in order to develop. However, the sperm cell does not
contribute any genetic material to the offspring.
 3) PARTHENOGENESIS: reproduction without
fertilization (persenyawaan)
PARTHENOGENESIS
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1) ARRHENOTOKY
unfertilised eggs develop into males
 Bees, ants, wasps
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2) THELYTOKY
Unfertilized eggs turn to female
 aphid
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EGG LAYING
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use ovipositor
variaton:
long, tubular- sticking eggs into hard suface
 Long-horned grasshopper, parasitic wasp
 Some are short
♀
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ovipositor
6-7 cm
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Eggs hatch to produce larva/nymph
METAMORPHOSIS:
 1) AMETABOLOUS
 Without metamorphosis or unclear
 Silverfish (Thysanura)
 2) HEMIMETABOLOUS (EXOPTERYGOTA)
 Incomplete m/morphosis (eggnymph/naiadadult)
 a) Paurometabolous: the nymph and the adult would live
in the same environment (grasshopper,cricket)
 b) Heterometabolous: the nymph & adult live in
different environments. For example, Odonata naiad live
in the water and cicada nymph underground, whereas the
adults are aerial.
 3) HOLOMETABOLOUS (ENDOPTERYGOTA)
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Complete m/morphosis (egglarvapupaadult)