Difference between revisions of "Insect Structure and Function"
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− | ==Insect Body== | + | ===Insect Body=== |
− | + | *Covered by an exoskeleton | |
− | The outer layer is called the '''epicuticle''' which is composed of proteins and covered by a waxy layer | + | **Provides support and protection to the living tissues |
− | + | **Acellular so is secreted by underlying epidermis | |
+ | **The outer layer is called the '''epicuticle''' which is composed of proteins and covered by a waxy layer | ||
+ | **The inner layers are the '''endocuticle''' and '''exocuticle''' which are composed of protein and chitin | ||
− | ==Insect Head== | + | *Body is '''metameric''' (divided into segments) |
− | [[Image: | + | |
− | [[Image:Insect Eyes.jpg|thumb|right|150px| | + | *Divided into head, body and abdomen |
− | [[Image: | + | **Articular membranes link segments allowing movement |
− | + | ||
− | + | ===Insect Head=== | |
+ | [[Image:Insect Head and eyes.jpg|thumb|right|150px|Alan Hadley]] | ||
+ | [[Image:Insect Eyes.jpg|thumb|right|150px|Alan Hadley]] | ||
+ | [[Image:Blow fly head.jpg|thumb|right|150px|Blowfly Head Close Up - Martin Pot - Wikimedia Commons]] | ||
+ | *Capsule of fused plates at the anterior end of the body | ||
+ | |||
+ | *One large pair of compound eyes | ||
+ | **Honeycomb like corneal facets | ||
+ | |||
+ | *Three simple ocelli | ||
+ | **Dorsal to compound eyes | ||
+ | |||
+ | *One pair of antennae | ||
====Antennae==== | ====Antennae==== | ||
− | + | *Form varies amongst insecta | |
+ | **E.g. long and segmented, short and squat etc. | ||
+ | |||
+ | *[[Hair - Anatomy & Physiology|Hairs]] sometimes present | ||
+ | |||
+ | *Aristae (bristles) sometimes present | ||
====Mouthparts==== | ====Mouthparts==== | ||
− | + | *Modification depending on feeding method | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | Larval mouthparts are prominent | + | *Insects which suck up liquified food have an expanded sponge like labellae |
+ | **Cannot penetrate skin | ||
+ | **Palps are also present which are sensory structures | ||
+ | |||
+ | *Insects which suck blood have long slender mouthparts for piercing skin | ||
+ | **Hypopharynx | ||
+ | **Mandibles | ||
+ | **Labrum | ||
+ | **Maxillae | ||
+ | |||
+ | *Larval mouthparts are prominent | ||
+ | **One pair of hooks | ||
+ | **Cephalo-pharyngeal skeleton | ||
**Mouthparts help identify larvae | **Mouthparts help identify larvae | ||
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====Wing==== | ====Wing==== | ||
− | [[Image:Insect Wing Venation.jpg|thumb|right|150px| | + | [[Image:Insect Wing Venation.jpg|thumb|right|150px|Alan Hadley]] |
*Insects usually posess two pairs of wings | *Insects usually posess two pairs of wings | ||
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*Foregut: | *Foregut: | ||
**[[Oesophagus - Anatomy & Physiology|Oesophagus]] | **[[Oesophagus - Anatomy & Physiology|Oesophagus]] | ||
− | **[[Crop - Anatomy and Physiology|Crop]] for temporary food storage | + | **[[Crop- Anatomy and Physiology|Crop]] for temporary food storage |
− | **[[Proventriculus - Anatomy & Physiology|Proventriculus]] | + | **[[The Proventriculus - Anatomy & Physiology|Proventriculus]] |
− | **[[Gizzard - | + | **[[The Gizzard - Anamtomy & Physiology|Gizzard]] present in insects which eat solid food |
***Muscular wall and teeth on inner surface | ***Muscular wall and teeth on inner surface | ||
Line 123: | Line 148: | ||
**Valves only let blood flow forwards | **Valves only let blood flow forwards | ||
− | *[[Aortic Arches - Anatomy & Physiology|Aorta]] | + | *[[The Aortic Arches - Anatomy & Physiology|Aorta]] |
*Branching [[Vascular System - Anatomy & Physiology|blood vessels]] | *Branching [[Vascular System - Anatomy & Physiology|blood vessels]] | ||
Line 166: | Line 191: | ||
**Recepticle for spermatozoa | **Recepticle for spermatozoa | ||
**Sperm remains viable for most of the female's life cycle | **Sperm remains viable for most of the female's life cycle | ||
− | + | [[Category:Insecta]][[Category:To_Do_-_Parasites]] | |
− | + | [[Category:To_Do_-_AimeeHicks]] | |
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− | [[ | ||
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− | [[Category: |
Revision as of 16:08, 6 July 2010
Insect Body
- Covered by an exoskeleton
- Provides support and protection to the living tissues
- Acellular so is secreted by underlying epidermis
- The outer layer is called the epicuticle which is composed of proteins and covered by a waxy layer
- The inner layers are the endocuticle and exocuticle which are composed of protein and chitin
- Body is metameric (divided into segments)
- Divided into head, body and abdomen
- Articular membranes link segments allowing movement
Insect Head
- Capsule of fused plates at the anterior end of the body
- One large pair of compound eyes
- Honeycomb like corneal facets
- Three simple ocelli
- Dorsal to compound eyes
- One pair of antennae
Antennae
- Form varies amongst insecta
- E.g. long and segmented, short and squat etc.
- Hairs sometimes present
- Aristae (bristles) sometimes present
Mouthparts
- Modification depending on feeding method
- Insects which suck up liquified food have an expanded sponge like labellae
- Cannot penetrate skin
- Palps are also present which are sensory structures
- Insects which suck blood have long slender mouthparts for piercing skin
- Hypopharynx
- Mandibles
- Labrum
- Maxillae
- Larval mouthparts are prominent
- One pair of hooks
- Cephalo-pharyngeal skeleton
- Mouthparts help identify larvae
Insect Thorax
- Divided into three segments
- Prothorax, mesothorax and metathorax
- Each segment has one pair of legs attached
- One or two pairs of wings may be present on the mesothorax and metathorax
Leg
- Leg is attached to the body by coxa
- Trochanter
- Femur
- Tibia
- Tarsus, which is composed of several segments
- Claw
- Usually six-segmented
Wing
- Insects usually posess two pairs of wings
- Diptera have a reduced second pair of wings called halteres for balance
- Membranous outgrowth of the integument
- Strengthened by a network of veins comprising breathing tubes (trachea) and blood vessels
- The wing venation can be used for identification
- Longitudinal veins
- Cross veins
- Open cells
- Closed cells
Insect Abdomen
- Segmented
- Soft
- Appendages present
- Copulatory claspers
- Ovipositor
- External genitalia
Respiratory System
- Branching trachea strengthened by spiral thickenings in the walls
- Trachea communicate with outside via spiracles
- Spiracles on side of body
- Chitinous openings
- Muscular control so can open and close at will
- Mounted on stigmatic plates
- Lead to trachea
- Muscular contactions of the body wall produce respiratory movements
- Shape of spiracles and stigmatic plates used for species identification
Alimentary and Excretary System
- The precise shape of the gut varies between arthropods
- The Alimentary canal is divided into fore, mid and hind gut
- Foregut:
- Oesophagus
- Crop for temporary food storage
- Proventriculus
- Gizzard present in insects which eat solid food
- Muscular wall and teeth on inner surface
- Midgut:
- Stores food
- Secretes enzymes for digestion
- Outlet for malpighian tubules (equivalent of the mammalian kidney)
- Hindgut:
- Water resorption
Circulatory System
- Branching blood vessels
- Haemocoele
- General body cavity
- Equivalent to the capillary circulation in mammals
- Contains haemolymph
- Ostia (openings) in the blood vessel walls allow return of blood to the heart
Nervous System
- Small brain above the oesophagus
- Chain of fused ganglia running along the floor of the abdomen and thorax
- Nerves are given off from chain
- Complex nervous system
- Well developed visual senses
Fat Body
- Large structure
- Cells containing fat vacuoles
- Lines the body cavity and internal organs
- Equivalent to the visceral and parietal peritoneum in mammals
- Food reservoir during hibernation or starvation periods
Reproductive System
- Most insects have seperate sexes
- Reproductive organs are analogous to mammals
- Spermatheca present in females
- Accessory female sex organ
- Recepticle for spermatozoa
- Sperm remains viable for most of the female's life cycle