Lectures 14-21 Flatworms & Related Phyla, Ecdysozoans Flashcards
Bilaterally symmetrical animals are part of the clade
Bilateria
Two benefits of bilateral symmetry
- Motor Coordination (able to move in a forward, directed movement)
- Cephalization (formation of a head region)
Bilateria are ____ organisms
Triploblastic
Triploblastic means
3 germ (embryonic cell) layers are developed during the blastula stage
The 3 germ layers are
-ectoderm
-endoderm
-mesoderm
The development of tissues and organs is due to
Distinct layer development during the Blastula Stage
Diploblastic means
2 germ layers
Having two germ layers gives rise to _____ and allows for _____
-tissues/organs
-greater complexity and formation
In mammals, the ectoderm forms (8)
-skin
-hair
-nails
-mouth lining
-tooth enamel
-brain
-nerves
-peripheral nerves
In mammals, the mesoderm forms (6)
-kidneys
-gonads
-circulatory system
-muscles
-notochord
-body cavity
In mammals, the endoderm forms (4)
-lining of GI tract
-respiratory tubes
-liver
-pancreas
Three clades of Bilateria are
-Lophotrochozoa
-Ecdysozoa
-Deuterostomia
Lophotrochozoa are also called
Protostomes
Lophotrochozoa, Ecdysozoa, and Deuterostomia all have ____ symmetry
Bilateral
4 Phyla of Lophotrochozoa
-Platyhelminthes
-Mollusca
-Annelida
-Acanthocephala
Protostomes (Lophotrochozoans) lack
Backbones
Flatworms are part of the phylum
Platyhelminthes < Lophotrochozoa < Bilateria < Metazoa
Acoelomate means
No body cavity
Four major groups of Platyhelminthes are
-Turbellaria (free living)
-Monogenea (ectoparasites of fish)
-Trematoda (endoparasites (flukes))
-Cestoda (endoparasitic tapeworm)
All Platyhelminthes are
-motile
-predatory
-reproduce sexually or asexually
Parasitic species of Platyhelminthes reproduce
Asexually
Flatworms lack (3)
-body cavity
-circulatory system
-anus
Flatworm gas exchange occurs
Across the surface of its body
Parasitic Groups of Platyhelminthes are
-Monogenea
-Trematoda
-Cestoda
Two vet significant Platyhelminthes groups
-Trematoda (liver fluke)
-Cestoda (tapeworms)
Turbellaria are (6)
-mostly free living
-some commensals
-some parasitic
-lack a body cavity
-have a ciliated epidermis for locomotion
-Part of Platyhelminthes
Protonephridial refers to
The excretory system of Flatworms - drains waste directly from the body
Feature of the Flatworm excretory system are
Flame cells
Dugesia tigrina (Planaria) is important as
A model for regeneration, aging, and stem cell biology
With the exception of Turbellaria, Platyhelminthes are (3)
-always parasitic/commensal
-have a ciliated epidermis in larva
-have a syncytial epidermis as adults
Monogenea means
One host/species
Ectoparasites of fish are in the class
Monogenea < Platyhelminthes < Lophotrochozoa < Bilateria < Metazoa
Monogenea live
On the skin / gills of fish
Life cycle of Monogeneans is
-simple
-eggs laid, they fall off the host and hatch, larva seeks a new host
Monogenea have a ____ attachment site
Posterior
Life cycle of Gyrodactylus is
-strange and atypical
-contains a baby within a baby within an adult!
-don’t produce many offspring
Fasciola hepatica is the
Sheep liver fluke
Flukes are part of the Class
Trematoda < Platyhelminthes < Lophotrochozoa < Bilateria < Metazoa
Adult flukes usually live in
The intestine of a vertebrate host
Flukes have (2)
-flat leaf-like body
-two suckers (oral used for attachment and feeding; ventral used for attachment)
Flukes attach to ____ by ____ and feed on _____
Mucosal wall;
Oral and Ventral Suckers;
Mucus, tissue fluid, and blood
Diecious means
Two separate genders
Monoecious means
Hermaphrodite (both male and female characteristics)
Flukes are mostly
Hermaphroditic
Excretion of flukes is through
The oral sucker (no true anus)
Liver fluke of sheep, cattle, other grazing animals, and humans is
Fasciola hepatica
Life cycle of Fasciola hepatica (6)
-eggs containing Miracidium pass in host faeces
-Miracidium enters the intermediate host (snail)
-asexual reproduction occurs within the snail (Sporocysts < Redia < Cercaria)
-Cercaria exits the snail, attaches to plant material and encysts into Metacercaria
-Plants with Metacercaria are eaten by the definitive host (sheep)
-Excysts in small intestine and moves to the liver
-cycle repeats
The second most important parasite in humans after malaria
Schistosomes (blood flukes)
Schistosomes differ from Fasciola hepatica (3)
-don’t attach to plants
-are dioecious (have separate sexes)
-active entry to final host through skin/ingestion
Cestoda are
Tapeworm parasite of the small intestine of vertebrates
Tapeworms lack
A mouth, digestive tract, and anus
How do Cestoda obtain nutrients?
Nutrients are absorbed across the body surface
How do Cestoda (tapeworms) reproduce
Reproductive system is copied/replicated as a chain
6 parts of Cestoda (tapeworm) and its function
- Scolex - attaches in intestinal crypts
- Neck - generation of new proglottids (ie. new reproductive system)
- Immature Proglottids
- Mature Proglottids - mature male and female organs
- Gravid Proglottids - uterus with fertilized eggs that detach and pass out of the host via faeces
- Strobila = neck + proglottids (can be a few mm to >20m long)
Beef Tapeworm Lifecycle
- Parasite crawls out of anus of host
- Ingested by intermediate host (cattle)
- Bladderworm in muscle
- Ingested by final / definitive host (humans) through consumption of undercooked meat
- Larval scolex attachment to intestine
The larval stage of the bladderworm (cysticercus) occurs in
Intermediate host
Taenia solium is known as
Pork tapeworm
The bladderworm in pigs affects the
Muscle
Echinococcus granulosus is also called
Hydatid tapeworm
One of the smallest Cestodes of domestic animals is
Hydatid tapeworm (Echinococcus granulosus)
Cats are NOT susceptible to
Hydatid tapeworm (Echinococcus granulosus)
Echinococcus granulosus (Hydatid tapeworm) definitive host is
Dog, dingo, fox
-harbours adult tapeworms
Echinococcus granulosus (Hydatid tapeworm) intermediate host
Sheep, cow, marsupials, humans, and other mammals
-Harbours larval stages
Lophotrochozoans with NO body cavity are the
Platyhelminthes
Lophotrochozoans WITH a body cavity are (2)
-Mollusca
-Annelida
Three types of body cavities and an example of each
-Acoelomate (no body cavity): Flatworms
-Coleomate (fluid filled cavity between gut and body wall lined with mesoderm): Vertebrates
-Pseudocoelomate (intermediate form of cavity lined with mesoderm on only one side): Nematodes
Molluscs are
Non segmented Lophotrochozoans
Annelids are
Segmented Lophotrochozoans
Acanthocephala are (3)
-parasitic
-bizarre
-affect small intestine of host
Acanthocephala have two host life cycles:
-arthropod intermediate host
-vertebrate definitive host
Macracanthorhynchus hirudinaceous are in the phylum
Acanthocephala
Macracanthorhynchus hirudinaceous have a proboscis that is (2)
-spinous
-penetrates the mucosa
M. Hirudinaceous life cycle is
-eggs pass in faeces
-eggs ingested by beetle larva (intermediate host)
-infects pig (definitive host) small intestine
*only found in wild pigs
The phylum Mollusca can be further divided into (4)
-Chitons
-Gastropods
-Cephalopods
-Bivalves
Torsion is when
The anus is over the head, as in Gastropods
Gastropods are (6)
-part of the phylum Mollusca
-non-segmented
-have a body cavity
-includes snails and slugs
-have a ventral nervous system
-have a primitive circulatory system
The sentient invertebrates are the
Cephalopods
The name Annelida means
“Little rings”
Phylum Annelida have these two features
-segmented
-body cavity
Three sub-phylum of Annelida and examples are
-Oligochaete (giant Australian earthworm)
-Hirudinea (leeches)
-Polychaete (fire worm and Christmas tree worm)
Seven benefits of having a Body Cavity
-independent movement of body wall and enclosed organs
-more space for complex organs and larger organ systems
-storage for eggs/sperm
-Coelomic Fluid protects internal organs
-waste removal
-functions as a hydrostatic skeleton
-circulatory function for oxygen / nutrients to cells (some animals)
Two reasons why organisms became segmented
-better control of body secretions
-diversification of function
Having a septum between segments allows for
Movement
Ecdysozoa means
“Ecdysis” = shedding
“-ozoa” = animal
Ecdysis means
Shedding (molting) of the exoskeleton
Ecdysozoans include (2)
-Nematodes
-Arthropods
Roundworms are
Nematodes
Major role of Nematodes are as
Decomposers
Roundworms are (7)
-microscopic
-interstitial dwellers
-many are parasitic
-non-segmented with cylindrical body
-free living
-have a “complete gut” (mouth and anus)
-mostly dioecious with internal fertilization
Dioecious means
Separate male and female
Triploblastic means
Three layers
The body cavity of Nematodes is
Pseudocoelom (ie. no structures) with longitudinal muscles
Nematodes lack
Respiratory and circulatory systems
Triploblastic cell layers of Nematodes are
-cuticle
-epidermis
-muscle
Nerve ring in Nematodes is called
Annuli
The brain of nematodes is a
Series of nerves surrounding GI tract anteriorly
Moulting or Ecdysis is associated with (3)
-change in environment
-reproduction
-behaviour
The cuticle layer of nematodes is
Complex and resilient to handle internal pressure
Nematodes live in
A liquid environment with high pressure
Movement of Nematodes involves
Moving in a serpentine (s-shape) by contracting muscles side to side
The hydroskeleton of nematodes
Has high internal pressure to bring the body straight
A model organism is ____ and an example is ____
An organism chosen by researchers wanting to understand broad biological principles
Ex. Caenohabditis elegans
The first multicellular organism to have its genome sequenced was
Caenorhabditis elegans (Nematodes, Ecdysozoans)
C.elegans (4)
-free-living soil nematodes
-has few cell types
-short generation time
-Eutely (defined number of cells)
Haemonchus contortus is also called
Barber’s Pole Worm
Haemonchus contortus (Barber’s Pole Worm) is (4)
-major parasitic pathogen of sheep and goats
-blood feeder
-occurs during summer rainfall areas
-resistant to antihelminthics
The Life Cycle of Haemonchus contortus (Barber’s Pole Worm):
-adult worms in the abomasum of sheep
-eggs pass with faeces
-First Larval Stage (L1) hatch and feed on bacteria in faeces
-Moult into L2 and L3 within the faeces
-L3 migrate and climb wet grass blades
-Sheep eat infected L3 grass
Hookworms are
Parasitic nematodes of humans and animals
Hookworm life cycle steps are
Skin —> bloodstream —> heart —> lung capillaries —> alveolar space —> move to trachea to be swallowed —> mature in small intestine —> pass through faeces
Hookworms can cause ___ especially in ____
Anemia; children/puppies
Ascarids are
Large intestinal worms of mammals that compete with the host for food
Ascarids cause disease by
Occluding intestine and aberrant migration in the host
Female Ascarids lay
Desiccation-resistant eggs (eggs don’t hatch in environment)
An important Ascarids of horses is
Parascaris equorum
Parascaris equorum life cycle
-eggs pass in faeces and can survive on pasture for years
-eggs mature but DO NOT hatch
-eggs ingested by horse and larva hatches in small intestine
-larva burrow into wall of small intestine and find blood vessels
-larva travel to the lungs and burst alveoli
-larva travel to trachea to be swallowed
-maturation occurs in small intestine
*takes up to 12 weeks
Parascaris equorum has these effects on the equine host (5):
-pneumonia
-loss of energy
-colic
-intestinal perforation
-intestinal obstruction
Pinworms are (4)
-Nematodes - small worms in the rectum of mammals
-not pathogenic, they feed on bacteria
-two species affect the horse
-one species affects humans
Dirofilaria immitis is also called
Heartworm
Adult Dirofilaria immitis affect
Right side of heart and pulmonary artery in dogs, cats, foxes, and humans
HEARTWORM
Heartworm is transmitted by
Mosquito salivary glands
The only worm species that becomes an Intracellular parasite is
Trichinella spiralis
Trichinella spiralis is transmitted
Mammal to mammal via undercooked meat
Trichinella spiralis larva are found in _____ while adults are found in _____
Nurse cells within skeletal muscle; intestine
Trichuris trichiura is also called
Whip worm
Nematomorpha are
Parasites of insects (Gordian worms and Horsehair worms)
Nematomorpha only infect
Insects via water
Arthropods are part of the phylum
Ecdysozoa
Arthropods means
“Jointed feet”
Arthropods are (4):
-segmented
-located in all major environments
-play a major role in food chains, as pollinators/decomposers/scavengers
-decreasing in diversity due to agriculture and pesticide control
“Success” of a species is based on (3)
-species
-habitat diversity
-total numbers
Why are arthropods so successful (4)
-adaptable body plan
-ability to thrive in a range of environments
-segmented, fused body (head, thorax, abdomen)
-exoskeleton with jointed appendages
Three specializations of Arthropod segments are
-Head (sensation/feeding)
-Thorax (movement)
-Abdomen (intestine/reproduction)
Having multiple segments means
Having multiple functions
Jointed appendages of arthropods are used for
Moving and feeding
Early forms of the Arthropod body plan were
Pronounced, segmented, and had little specialization
Tagmatisation / Tagmosis means
Fusion of segments to produce “super segments” or Tagmata
Tagmata are
Body regions (ie. head, thorax, abdomen)
Tagmata allowed for the
Specialization of body form, function, and appendages
Features of Arthropods (9):
-exoskeleton
-segmentation
-Tagmata (head, thorax, abdomen OR head, trunk OR cephalothorax, abdomen)
-appendages
-complex respiratory structures
-circulatory system (lacks haemoglobin)
-ventral nervous system
-complex excretory system
-sexual reproduction
Arthropod appendages are used for (4)
-mobility
-sensing
-feeding
-reproduction
Exoskeleton is made of
Protein and chitin
Three cons of Ecdysis are
-must moult in order to grow
-temporary vulnerability
-takes energy
Exoskeleton provides (3)
-physical and physiological protection
-muscle attachment
-body support
Five lineages of Arthropods
-Trilobates (extinct)
-Chelicerates
-Hexapods
-Crustaceans
-Myriapods
Insects and 6 legged relatives are the
-chelicerates
-hexapods
Two groups of Arthropods based on mouthparts are
-Chelicerate Mouthparts
-Mandibulate Mouthparts
Chelicerate Mouthparts are (3)
-used for grasping food
-fang like or pincer
-hollow and carry venom (in spiders)
Mandibulate mouthparts use
Mandibles for chewing/grinding food
Chelicerates include
-ticks
-mites
Arachnids include
-spiders
-scorpions
-ticks
-mites
Chelicerate body is
Simple, includes cephalothorax and abdomen
Chelicerate mouthparts possess (2)
-Chelicerae (paired feeding appendages ie. fangs or pincers)
-Pedipalps (feeding and sensory)
Chelicerates lack
A true antennae
What has 8 eyes and 4 pairs of legs
Chelicerates
The hypostome is
An additional mouth part in chelicerae used for sucking blood
Palps are used
In chelicerae to cut flesh
Ticks, mites, spiders, and scorpions are all
Chelicerates
Two chelicerates of veterinary importance are
-Ticks (Acarines)
-Mites
Ticks are (2)
-external parasites of mammals, birds, and reptiles
-heavy blood feeders that engorge
Saliva of ticks (3)
-assists with feeding
-carries disease-causing microorganisms
-secretes neurotoxins
Babesia is
A microorganism carried by ticks that causes tick fever or canine erlichiosis
Most venomous tick species is
Ixodes holocyclus
Ixodes holocyclus
Secretes neurotoxins that cause tick paralysis
Ticks can cause
Blood loss leading to anemia and skin damage
Rhipicephalus (Boophilus) australis is also called
Cattle Tick
Cattle Tick Lifecycle
-21 days
-has one host (cattle) where the entire life cycle occurs usually in the shoulder/neck region of the host
-egg —> larva —> nymph —> adult female or male
Larval development of Cattle Tick can take
-2 months in the summer
-up to 7 months in the winter
Ticks have denticulated hypostome which means
Teeth are backwards so it locks into the host
Mites are
mostly free living and not parasitic
A parasitic mite is
Scabies which lives in the burrows of the skin
Scabies mites cause
Mange
Mange is ___ and causes (3)
An infectious condition associated with:
-severe dermatitis
-hair loss
-scabs and keratinized skin
The family Culicoidea includes
Mosquitos
Two Culicidae subfamilies of medical importance include
- Anophelinae
- Culicinae (Culex and Aedes)
Mosquito anatomy includes (5)
-abdomen
-thorax
-head
-legs
-proboscis
The proboscis of mosquitos can cause (3)
-irritation (Fly Worry)
-allergy
-transmission of viruses
Only ____ mosquitos can bite and transmit disease
Female
Male mosquitos have (2)
-longer palps
-long hairs on antennae (feather appearance)
How many species of mosquitos are there in Australia
72
Culicinae mosquitos includes (2)
-Aedes (aggressive day bites, hard to eradicate)
-Culex (active at dawn/dusk, common)
Anophelinae mosquito includes
Anopheles (dawn/dusk, can bite at night)
The proboscis of Aedes is
Pointed
The proboscis of Culex is
Rounded
The palps of Anopheles are ____ while Culex palps are ____
Long; short
Three mosquitoes of medical importance are
-Culex
-Aedes
-Anopheles
Life cycle of mosquitos depends on
Temperature
Upper threshold life cycle of mosquitos means
High temperature, quick life cycle
Over wintering in mosquitos means
Temperature is too low for egg laying
Lower threshold life cycle for mosquitos means
Only basic physiological functioning
Life cycle of mosquitos
-Eggs laid on/above stagnant water surface
-Larva takes air from water surface via siphon or respiratory tube
-Pupa takes air from water surface
-Adult emerges from pupa at water surface
Mosquito larvae “breathe” through
A siphon
Mosquitos are anthrophilic which means
Anthro = humans
Philic = loving
Moquitos can perceive (4)
-CO2
-skin emanations
-temperature
-visual stimuli
Culex annulirostris are
Fresh water breeding mosquitoes
Culex annulirostris can transmit (4)
-Ross River Virus
-Barmah Forest Virus
-Heartworm
-Japanese encephalitis
Japanese encephalitis is (2)
-New in Australia
-transmitted by Culex annulirostris
Aedes vigilax are
Saltmarsh mosquitoes
Three diseases that Aedes vigilax transmit are
-Heartworm
-Ross River virus
-Barmah Forest Virus
Aedes notoscriptus is a
Container breeding mosquito
Australian backyard mosquito is called
Aedes notoscriptus
Aedes notoscriptus can transmit
Heartworm
The time from blood meal to egg laying in mosquitos is called
Gonotrophic Cycle
The time from infection of mosquito to infection of vertebrate host is called
Extrinsic Incubation Period (EIPs)
Which mosquito is invasive and a risk to public health
Aedes
What factors influence globalization (3)
-environment
-biology
-social
What affects the emergence of Vector Borne Disease (VBD)
Temperature
An increase in temperature has what effects on VBD (3)
-vector-biting rate
-vector development rate
-pathogen replication
A decrease in temperature has what effect on VBD
-vector survival
Mosquitos are insects which means they are
Ectotherms and affected by temperature
The effects of climate change are
Multiple and non-linear
Vector competence involves (4)
-isolation of the virus
-infection
-transmission
-association on field
5 important VBD are
-malaria
-yellow fever
-dengue fever
-filariasis
-encephalitis
Uncommon Viral VBDs of mosquitos include (4)
-west Nile
-rift valley
-Ross river
-chikungunya
Prevention and control of mosquitos involves (2)
-insecticides and repellants
-environmental management
Challenges in controlling VBDs include (3)
-insecticide resistance
-lack of expertise in vector control
-lack of surveillance
How can one interrupt the mosquito life cycle (3)
-maintain rainwater tanks
-protect yourself
-remove breeding sites in your yard
Insects (Hexapoda) are
-diverse
-abundant
Super segments are
3 Tagmata: head, thorax, and abdomen
The thorax of Insecta (Hexapoda) has
-3 pairs of legs
-sometimes 2 pairs of wings
Insecta (Hexapoda) adapted to terrestrial environments through (9)
-small size
-exoskeleton
-jointed, hardened locomotory appendages
-excretory system
-advanced respiratory system
-advanced nervous system
-advanced sensory system
-internal fertilization
-resistant eggs
The excretory system of Insecta (Hexapoda) is
-Composed of tubules that pass through the body
-Waste excreted as uric acid
The respiratory system of Insecta (Hexapoda) has
-Spiracles on the body that open to the outside
-Trachae (tubules) that ramify through the body and direct oxygen to supply tissues
The cerci in cockroaches
Detect changes in air pressure
The Malphigian tubules in Insects is used for
Excretion
Arthropod eyes are ancestrally
Compound eyes
Insect evolution is associated with
Evolution of plants
The most abundant insect are
Beetles
Apterygota (4)
-primitively wingless
-simple mouthparts
-invasion of land
-includes Springtails and Silverfish
Palaeoptera (4)
-evolution of wings
-simple insects with simple development
-wings did not fold over abdomen
-includes Dragonflies and Mayflies
The development of wings that fold over the abdomen was seen in
Orthropteroida
Grasshoppers, praying mantis, cockroaches, and stick insects are part of
Orthropteroida
Enhanced inversion of insects led to two lineages:
- Hemimetabolous (simple development)
- Holometabolous (complete metamorphosis)
Hemimetabolous insects are (2)
-hemipteroida (includes lice, bed bugs, kissing bugs, etc)
-retain simple development
Life cycle of Hemimetabolous insects includes
- Egg
- Nymphs (juvenile forms that look like adults but lack wings and are not sexually mature)
- Moulting stage
- Adults (sexually mature and may develop wings)
Trypanosome cruzi (4)
-causes Chagas’ disease
-transmitted by Assassin or Kissing Bugs
-occurs mostly in South America
-chronic disease (scarring and swelling of heart, liver, GI tract)
Bed bugs have a life cycle that involves
5 nymph stages
True metamorphosis is seen in
Holometabolous development
Holometabolous development involves
- Egg
- Larva specialized in feeding, growth, and development
- Larva moults to Pupa (internal, transitional phase)
- Adult specialized in reproduction, dispersion, and egg laying (can be feeding or non feeding)
Holometabolous groups include (3)
-Neuropteroida
-Hymenopteroida
-Panorpoida
Advantages of true metamorphosis (3)
-allows adults to occupy different habitat from larvae
-exploit different food resources as larvae and adults
-metamorphosis allows insect to escape from temporary habitat
Lepidoptera includes
-moths
-butterflies
Coleoptera includes
-beetles
-weevils
Siphonaptera includes
Fleas
Diptera includes
-flies
-mosquitoes
Three main insect groups of vet significance are
-lice
-fleas
-flies (mosquitoes)
Lice develop through
Hemimetabolous development
Lice are (3)
-permanent ectoparasites
-small, wingless and dorso-ventrally flattened
-host specific
Hooked tarsi are
Terminal segments on legs of lice that allow them to grab onto hair/feathers and hook onto host
Sucking lice (2)
-affect only mammals
-feed on blood
Chewing lice (2)
-affect mammals and birds
-feed on skin
Lice eggs are called
Nits
Lice cause harm to the host by (4)
-irritation, skin damage
-anaemia
-vectors of disease
-intermediate hosts of parasites
Mallophaga
Chewing lice
Anoplura
Sucking lice
Life cycle of lice is
- Egg (nit)
- 3 nymph stages
- Adult
Takes ~21 days
Hematopinus
Blood sucking louse of pigs and ruminates
Sheep body louse feeds on
Skin and wool, decreases production
Vectors of typhus are
Head/body louse
Pubic louse is (3)
-host specific to humans
-sexually transmitted
-can also infect eyebrows/eyelashes
Fleas are (4)
-not permanent ectoparasites
-small, laterally compressed
-have muscular hind legs
-Holometabolous development
Life cycle of fleas
- Eggs laid on host
- Larvae contain chewing mouthparts and feed on detritus
- Pupae
- Adult have sucking mouthparts and are blood feeders
Fleas cause harm to the host through (3)
-direct harm (hypersensitivity, blood loss, anaemia)
-vectors of bacteria and viruses
-intermediate host to cucumber tapeworm
Ctenocephalides felis is
The cat flea
Major problem in the sheep industry is
Flystrike (Blow Fly)
Life cycle of Ctenocephalides felis (cat flea)
Off Host:
1. Larvae feed on detritus
2. Pupa live off energy stored from larva phase
On Host:
3. Adults drink host blood
4. Eggs
Bot fly maggots
Grow in internal organs
Myiasis
Infection of living tissue with maggots
The dominant aquatic arthropod are
Crustaceans
Crustaceans have
Extensively specialized appendages
Copepods are (4)
-an important group of crustaceans
-important food source
-can be parasitic on fish (exploits feeding behaviour by living on tongue as female or in the gills as male)
-used to control dengue mosquitos
Crustaceans have two Tagmata:
-Cephalothorax (head and thorax)
-Abdomen
