Lecture 2
Phylum Arthropoda Class: Insecta
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Abdominal Appendages(Head- Thorax- Abdomen)
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•Compound Eyes (C) -made up of many small lenses, called ommatidia.
•Purpose: detect movement, light intensity and color.
•Simple Eyes (S) -“ocelli” Insects have 0-3 simple eyes. Purpose: detect light intensity.
Head appendages – 1-Eyes
C
C
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IIIIInsect Head – 2- Antennae
• Insects have one pair of antennae.• May have the function of touch, smell, and in
some cases, hearing.• Used for navigation, food location, grasping (in
some species)• Used for detection of:
• temperature• chemicals produced by plants or other foods• chemicals produced by other members of their
species (pheromones)
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Insect Head – 2-Antennae• Shape, number, and size of the segments are frequently used for
identification.• The overall appearance of the antennae are also used in identification.
plumoselamellate serrate filiform
geniculate
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antennae
The antennae are a pair of sense organs located nearthe front of an insect's head capsule. Althoughcommonly called "feelers", the antennae are muchmore than just tactile receptors. They are usuallycovered with olfactory receptors that can detectodor molecules in the air (the sense of smell). Manyinsects also use their antennae as humidity sensors,to detect changes in the concentration of watervapor. Mosquitoes detect sounds with theirantennae, and many flies use theirs to gauge airspeed while they are in flight.
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Antennal Segments
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Types of Antennae
a. and f. Filiform –thread-like h. Geniculate –elbowed
b. Moniliform –bead-like i. Lamellate –plate-like
c. Setaceous –hair-like g. Capitate – head-like (less enlarged at the tip would be clavate –clublike
d. Serrate –sawtoothed j. Plumose –plumed or feather-like
e. Pectinate –comb-like 9Prof. Dr. Badr El-Sabah / Lecture2
Setaceous --bristle-like
Dragon fly10
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Filiform -- thread-like
Ground beetle11
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Serrate -- sawtoothed
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Moniliform -- bead-like
Termite13Prof. Dr. Badr El-Sabah / Lecture2
Clavate --gradually clubbed
Carrion beetle 14
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Capitate -- abruptly clubbed
Butterfly 15
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Lamellate -- nested plates
Scarab / Rhinoceros beetle16
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Pectinate -- comb-like
Fire-colored beetle 17
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Plumose -- brush-like
Mosquito18
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Geniculate -- elbowed
Ant 19Prof. Dr. Badr El-Sabah / Lecture2
Aristate -- pouch-like with lateral bristle
House fly20Prof. Dr. Badr El-Sabah / Lecture2
Types of Mouth Parts
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Orientation of Mouthparts
• Prognathous –projecting forward (horizontal)
• Hypognathous – projecting downward
• Opisthognathous –projecting obliquely or posteriorly
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1. CHEWING MOUTH PARTS - Animals w/ these are
likely to feed upon plant material such as leaves Ex.
Grasshopper & Locust
2. PIERCING & SUCKING MOUTH PARTS:
- These animals will feed on different food sources Ex.
Mosquito sucks blood from its host
piercing/suckingchewing
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Generalized insect MOUTHPARTS
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There are five different structures which are used for
the initial collection and processing of food:- Labrum -
a cover which may be loosely referred to as the upper
lip. Mandibles - hard, powerful cutting jaws. Maxillae -
'pincers' which are less powerful than the
mandibles. They are used to steady and manipulate
the food. They have a five segmented palp which is
sensory and often concerned with taste. Labium - the
lower cover, often referred to as the lower lip. It
actually represents the fused pair of ancestral second
maxillae. They have a three segmented palp which is
also sensory. Hypopharynx - a tongue-like structure in
the floor of the mouth. The salivary glands dischargesaliva through it. Biting Mouthparts.
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From Gullen & Cranston 2000
The mouthparts of most
insects are highly
specialized for a single
purpose.
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The paired mandibles and maxillae are formed into
needle-like structures (stylets) which are enclosed by
the labium. When a mosquito 'bites', the
pointed and barbed pair of maxillae penetrate the
dermal tissue of the vertebrate to anchor the
mouthparts in the tissue. This also provides leverage
when the other mouthparts are inserted. The sheath-
like labium slides back and the remaining mouthparts
pass through its tip and into the tissue. The mosquito
injects saliva, which contains anticoagulants, into the
tissue to stop the blood from clotting. The labrum acts
like a tongue and is used to suck up the blood.
Piercing & Sucking Mouthparts.
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3. LAPPING MOUTH PARTS:
- An example of an insect wh/ has these is the housefly as it
feeds on various food sources
4. SIPHONING MOUTH PARTS:
- The insect will have a very long coiled structure called the
PROBOSCIS
- The PROBOSCIS is used for feeding on the nectar found
in flowers
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Adult housefly mouthparts.
from Gullen & Cranston 2000
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Mouthparts are soft and end in spongy pads.
Houseflies depend on their keen sense of smell,
provided by their antennae. For tasting andconsuming meals, the insect uses its proboscis, a
plunger-like appendage that extends from the bottom
of the head. Two small, antenna-like feelerscalled maxillary palps allow the fly to taste its food The
end portion of the proboscis, called the labellum,
terminates in a spongy mouth, where the fly slurps its
food. It feeds only on liquids. It regurgitates part of its
last meal on to its next meal. This liquid and the
enzymes in it soften and liquefy part of the solid which
the fly then mops up. This is another way of spreading
germs. Also it frequently defecates while feeding.Sponging & Sucking Mouthparts.
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from Gullen & Cranston 2000
Specialized mouthparts of butterfly.
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Found in butterflies and some moths (Lepidoptera). The
probiscis (galea) is a modification of the maxillary galea
found in the more primitive madibulate (chewing)
mouthparts, as seen in the cockroach. The probiscis
consists of paired galea which, during feeding, fit
together to form a tube that is used to suck up nectar (it
acts like a straw). When not in use the proboscis is
coiled and held close to the underside of the head.The
Morgan's sphinx moth, Xanthopan morgani , has
the longest proboscis at 30 to 35 cm in length. SiphoningMouthparts
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5- Cewing Lapping . Multi-purpose mouthparts of the honey
bee, a facilitation & consequence of social life.
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This is accomplished by having both mandibles and a
proboscis. The mandibles are the paired "teeth" that
can be open and closed to chew wood, manipulate
wax, cleaning other bees, and biting other workers or
pests (mites). The proboscis is mainly used for
sucking in liquids such as nectar, water and honey
inside the hive, for exchanging food with other bees
(trophallaxis), and also for removing water from
nectar. The workers can put a droplet of nectar
between the proboscis and the rest of the mouth parts
to increase the surface area, and slowly moving the
proboscis back and forth. Chewing & SuckingMouthparts
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THANKS
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