Arthropods Flashcards
What makes Arthropods so successful?
1) Adaptable body plan
2) Thrive in a range of environments
3) Segmented body - “blocks”
4) Segments are fused allowing greater control
5) Exoskeleton with joint appendages
Tagmatisation/tagmosis
Fusion of segments producing “super-segments”
Arthropod Features (9)
1) Exoskeleton
2) Segmentation
3) Tagmata
4) Appendages
5) Respiratory structures
6) Circulatory system
7) Ventral nervous system
8) Complex excretory system
9) Sexual reproduction
what type of respiratory system do arthropods have?
Haemocoel system
Means they have an open system
Ecdysis
Moulting, allows for growth
Temporary vulnerability
Energetically expensive
Exoskeleton of arthropods are made of what? (2)
1) Protein
2) Chitin
What are the 5 lineages of Arthropods (both extinct and living): [5]
1) Trilobites - extinct
2) Chelicerates
3) Hexapods - (insects/6-legged relatives)
4) Crustaceans
5) Myriapod
What are the two categories of mouthparts
1) Chelicerate
2) Mandibulate
Chelicerae
Group of mouthparts
Chelicerate mouthparts are for grasping
Mandibules
Group of mouthparts
Mandibles are for chewing
What are the two groups are chelicerae and what are their functions
1) Chelicerae: Paired feeding structures modified into fangs (spiders) or pincers
2) Pedipalps: [palps] Feeding or sensory
Chelicerates
Group of organisms including
1) Spiders
2) Scorpions
3) Ticks
4) Mites
*4 Pair of legs, 8 legs total
How many legs to chelicerates have?
4 pairs of legs, 8 legs total
Two types of ticks with veterinary importance (2)
1) Babesia –> Tick fever
2) Ixodes holocyclus –> neurotoxin -> Tick paralysis
3) Boophilus –> Cattle tick
What are three ways ticks impact host
1) Anaemia –> Blood loss
2) Secrete toxins
3) Transmit pathogens
Boophilus life cycle
Cattle tick
1) Adult ticks on cattle
2) Engorged female lays 3000 eggs, and dies
3) Larval development: 2 months in summer; 7 months in winter; leads to “spring rise”
4) Larva quests
5) Attaches to host, feeds, moults
Why is it so difficult to remove a tick?
They have a hypostome
Hypostome
Toothed hypostomes are parts of the tick attachment mechanism which have backwards projecting teet
Pulling out can cause an anaphalactic reaction
Mites General Features
Ectoparasite
Transmission: Predominantly by contact
Ex) Scabies
Scabies
Ectoparasite Transmission by contact Cause mange Associated with severe dermatitis Characterized by hairloss, scabs, keratenized skin with mites
How many legs do Mandibulates have?
3 pairs of legs, 6 legs in total
Mandibulates general features
3 pairs of legs, 6 legs total
2 pairs of wings
Beetles are most abundant
Complex bodies - 3 tagmata (head-thorax-abdomen)
Features of Insecta
Hexapods - 6 legs
1) Exoskeleton
2) Excretory system
3) Advanced respiratory system
4) Advanced nervous system
5) Advanced sensory system
6) Internal fertilization
7) Resistant eggs
Apterygotes
Primitively wingless insects
Mostly simple mouths
What are the 5 classes of insects
1) Apterygota
2) Palaeoptera
3) Orthopteroida
4) Hemipteroida
5) Neuropteroida/Hymenopteroida/Panorpoida
Palaeoptera
Evolution of wings
Simple insects with simple development
Wings didnt fold over abdomen
Orthopteroida
Development of wings that fold over abdomen
Hemipteroida
Retain simple development
Lifecycle: Egg, Juvenile [moult], Adult
How many nymph stages do bedbugs have?
5
Neuropteroida/Hymenopteroida/Panorpoida
True metamprphasis
Holometabolous development
What is the scientific name for metamorphosis
Holometabolous development
Advantages to metamorphasis
1) Adults occupy completely different habitat compared to larval stage
2) Larva and adults exploit different food
3) Allows insects to escape temporary habitats
Insects of veterinary significance (3)
1) Fleas
2) Lice
3) Flies
Fleas general information
non-perminant ectoparasites
host: dogs, cats, poultry, humans
Adult: blood-feedling - sucking mouthparts
Eggs: on host or in nest
Larvae: Detritus feeder including blood and faeces
How do fleas cause harm? (3)
1) Direct harm: Flea-bite allergy (hypersensitivity)
2) Vector: Bacteria (plague), virus (myxomatosis)
3) Intermediate host: fleas host to “cucumber” tapeworm of dogs and cats
ex) Dipylidium caninum
What is the name of the cat flea?
Ctenocephalides felis
Ctenocephalides felis
Complete metamorphasis - holometabolous-development
life cycle of cat flea
Ctenocephalides felis
1) egg derived from parent and found in bedding/carpets/soils/nests
2) larvae feeds on detritus/faeces
3) Pupa: lives off energy it stores when larvae
4) Adult: drinks host blood
Lice general features
Permanent ectoparasite
Small, wingless, flattened body
Split into biting lice and non-biting lice
Mallophaga (M)
Biting lice of mammals and birds
Anoplura (A)
Biting lice of mammals only
In what ways do lice cause harm to host?
1) Pediculosis: louse infection
2) Irritation, skin damage (M&A)
3) Anaemia from blood loss (A)
4) Vectors of bacteria eg, typhus (A)
5) Intermediate hosts: Tapeworms (M)
Human head/body louse name
1) Pediculus humanus
2) Pediculus capitis
Human pubic louse name
Phthirus pubis
Myiasis
Invasion of living tissue by dipteran larvae (blowfly strike)
Huge economic loss in sheep industry (lucilia cuprina)
Ex) botfly, screw worm flies
*All have holometabolous development
Mosquitos general features
- family Culicidae
- females feed on blood for protein source
- females feed multiple times on host for blood
Mosquitos in Australia transmit (3)
1) Ross River Virus (RRV)
2) Dengue fever
3) Barmah Forest Virus (BFV)
4) Dog heartworm
5) *Sometimes Malaria
Aedes aegypti
Mosquito adapted to human habitat
Transmits: Dengue Fever, Yellow Fever
Signs Dengue: fever, headache, muscle and point pains, haemorrhagic fever
Signs Yellow: Liver damage, jaundice, haemorrhagic fever
Aedes life cycle
2 habitats for life cycle
1) Larvae hatch in water
2) Pupae mature in water
3) Adults in terrestrial environment
4) Adults deposit eggs
Crustacean general features
Dominant aquatic arthropod
Specialized appendages
Many small crustaceans important in plankton
Plankton
Passive drifters, weak swimmers, most small, many microscopic
Includes larval forms but also larger crustaceans
Copepods
Important group of crustaceans
Food source in aquatic systems
Some copepods are predatory
Can be parasitic to fish
Which copepods are used to control dengue mosquito?
Mesocyclops species
