Difference between revisions of "Insecta"
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*Insects which suck up liquified food have an expanded sponge like labellae | *Insects which suck up liquified food have an expanded sponge like labellae | ||
**Cannot penetrate skin | **Cannot penetrate skin | ||
− | **Palps | + | **Palps are also present which are sensory structures |
*Insects which suck blood have long slender mouthparts for piercing skin | *Insects which suck blood have long slender mouthparts for piercing skin |
Revision as of 18:46, 24 October 2008
This article is still under construction. |
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Classification
The phylum arthropoda is divided into several subphylums including Chelicerata (which includes the arachnids), Myriapoda, Hexapoda (which includes the insecta), Crustacea and Trilobitomorpha. These are then divided into many classes. The two of major veterinary importance are the insecta and arachnida classes.
Structure and Function
Insect Body
- Covered by an exoskeleton secreted by underlying epidermis
- Divided into head, body and abdomen
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
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 in identification
Insect Abdomen
Respiratory System
Spiracles
Alimentary and Excretary System
Nervous System
Fat Body
Reproductive System
Life cycles
Fleas
Lice
Nuisance flies
Biting Flies
Myiasis Flies
- Oestrus ovis causes infection in nasal cavity
- Hypoderma bovis in myositis
- Cause skin infections, Simuliidae and Ceratopogonidae transmit onchocerciasis, flies involved in cutaneous habronemiasis and stephanofilariasis, protozoal skin infections
- Flea bite hypersensitivity
- Culicoides hypersensitivity