| Line 13: |
Line 13: |
| | | | |
| | | | |
| − | ==Structure and Function== | + | ==[[Insect Structure and Function]]== |
| | | | |
| − | ===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===
| |
| − | [[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====
| |
| − |
| |
| − | *Form varies amongst insecta
| |
| − | **E.g. long and segmented, short and squat etc.
| |
| − |
| |
| − | *[[Hair - Anatomy & Physiology|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====
| |
| − | [[Image:Insect Wing Venation.jpg|thumb|right|150px|Alan Hadley]]
| |
| − | *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 - Anatomy & Physiology|trachea]]) and [[Vascular System - Anatomy & Physiology|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 - Anatomy & Physiology|trachea]] strengthened by spiral thickenings in the walls
| |
| − |
| |
| − | *[[Trachea - Anatomy & Physiology|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 [[:Category:Arthropods|arthropods]]
| |
| − |
| |
| − | *The Alimentary canal is divided into fore, mid and hind gut
| |
| − |
| |
| − | *Foregut:
| |
| − | **[[Oesophagus - Anatomy & Physiology|Oesophagus]]
| |
| − | **[[Crop- Anatomy and Physiology|Crop]] for temporary food storage
| |
| − | **[[The Proventriculus - Anatomy & Physiology|Proventriculus]]
| |
| − | **[[The Gizzard - Anamtomy & Physiology|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====
| |
| − |
| |
| − | *[[Heart - Anatomy & Physiology|Heart]] situated dorsally
| |
| − | **Valves divide [[Heart - Anatomy & Physiology|heart]] into compartments
| |
| − | **Valves only let blood flow forwards
| |
| − |
| |
| − | *[[The Aortic Arches - Anatomy & Physiology|Aorta]]
| |
| − |
| |
| − | *Branching [[Vascular System - Anatomy & Physiology|blood vessels]]
| |
| − |
| |
| − | *Haemocoele
| |
| − | **General body cavity
| |
| − | **Equivalent to the capillary circulation in mammals
| |
| − | **Contains haemolymph
| |
| − |
| |
| − | *Ostia (openings) in the [[Vascular System - Anatomy & Physiology|blood vessel]] walls allow return of blood to the heart
| |
| − |
| |
| − | ====Nervous System====
| |
| − |
| |
| − | *Small brain above the [[Oesophagus - Anatomy & Physiology|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
| |
| | | | |
| | ==Life cycles== | | ==Life cycles== |