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22 Cards in this Set
- Front
- Back
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Micropredators
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Blood feeding
Mosquitoes, tsetse flies, tabanids Short-lived, adults feed frequently and quickly in minutes Specialised mouthparts, require blood for egg production Females may feed several times in weeks/months Need to live long enough to transfer parasite with a relatively rapid life-cycle Transmit parasites with short-cycles Tabanid bites painful and often interrupted |
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Ticks
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Long-lived ectoparasite arachnids
Mostly free-living on ground Feed infrequently for long periods (days/weeks) Specialised mouthparts Synchronise life-cycles with host to ensure infective stages are ready when feeds Jointed legs and exoskeleton, bilateral, metamorphosis, moult between growth stages, metameric segmentation may not be obvious |
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Parasite transmission
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Flies attracted to host by odour
Mechanical: parasite on mouthpart, don't develop in fly, painful bite, acts as flying syringe (Tabanid) Biological: develop in fly rapidly (Mosquito) |
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Metamorphosis
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Change in form/structure during development
Dramatic: immature insect to adult |
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Holometabolous life cycle
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Complete metamorphosis
Egg, larva, pupa, imago, adult Adults and larvae develop in different environments Different species live in different environments with different adaptations Adults of some species feed on vertebrate blood |
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Tsetse fly
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Larvae singly in mother's uterus until mature
Voided and pupariate |
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Order Diptera
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Flies, minority suck blood
One pair wings on 2nd thoracic segment 2nd pair modified to halteres for gyroscope to aid flying Holometabolous life cycle, most lay eggs, some larvae Most free living, some ectoparasitic Nematocera: long, filamentous antennae, many segments, mosquitoes Brachycera: antennae with no more than 3 segments, tabanids, tsetse, keds |
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Mouthparts of blood feeding flies
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1 pair mandibles: strong toothed jaws
1 pair maxillae: accessory jaws, lobes, palps, sensory and handle food Upper lip: labrum Lower lip: labium, 2 pairs maxillae united, 4 lobes and sensory maxi palps Epipharynx: tongue-like lobe, roof of mouth Hypopharynx: tongue-like lobe, floor of mouth |
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Family Culicidae
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Mosquitoes
Soft body, filamentous, segmented (13-15) antennae, palps porrect (face forward), scales on body and wings, wings have characteristic venation and scales, eggs, larvae and pupae adapted to still (lenthic) water Female: pilose (sparse hair) antennae, 1 pair wings, scales on head and palps, suck blood, painless Male: plumose (many hairs) antennae and palps, proboscis of labium and labellar, lobes hold on to thin maxillae and mandibles and hypopharynx, plants |
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Plasmodium transmission
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Life cycle in mosquito 10-12 days, temperature dependent
Female lives 1-2 weeks in tropics, 1-2 months in temperate Takes meal, eggs develop and laid in 2-3 days, takes another meal, more eggs etc, up to 1000 1 meal per batch eggs - Gonotrophic cycle If parasite picked up in first feed and survives 2 weeks it will infect another host Parasite lifecycle from uptake to sporozoites in mosquito salivary glands just fits female life time |
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Family Tabanidae
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Horse flies/clegs
Hard body, compact fly, large head, bulbous eyes, often metallic and brightly coloured, no scales, 3-segmented porrect antennae, hexagonal discal cell Painful bite, persistant feeders, coarse slashing and piercing, frequently interrupted, labellar lobes remain wet with blood so parasites stay alive between bites |
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Tabanid feeding
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Maxillae and claws hold on
Cut with mandibles Labellar lobes form pseudotrachaae (chitonous tubes) and act as sponge before sucking to gut Blood for protein for eggs Males feed on nectar if at all |
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Family Glossinidae
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Tsetse fly
Medium/large, brown, 5-10mm, hard compact body, hatchet shaped discal cell, 3 segmented pendulous antennae with feathered aristae (bristles), wings fold like scissors, m&f suck blood and trypanosomes Males: claspers on ventral side of wing to hold female during sex |
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Tsetse fly feeding
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Long forward proboscis ensheathed in palps
Bulb at back, teeth at tip of labellum, pierce/break capillary to form blood pool, proboscis protected by palps, saliva with anticoagulant pumped down hypopharynx and into wound, food sucked up food channel by muscular pharyngeal pump, gut has symbiotic bacteria which digest blood, bacteria passed to larvae |
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Biological transmission of trypanosomes
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Different species cause sleeping sickness in humans and nagana in cattle
Develop for 15-35 days in fly Life span < 6 months Females feed 2-3 days, need several meals per larva 9-12 days development |
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Chelicerata: Araci
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Ticks and mites, 2 part body
Anterior: mouthparts, 1 pair chelicerae, 1 pair pedipalps, 4 pairs walking legs Posterior: no appendages, contains organs No waist, mouth forms tube of 2 chelicerae and ventral hypostome Ticks: Order Ixodida, large exposed toothed hypostome Mites: many orders, very small untoothed |
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Hard ticks
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Terminal capitulum: mouthparts, 4-segmented palps inserted on base capituli
2 dorsal chelicerae protruding from sheaths or ventral toothed hypostome Sexual dimorphism: scutum covers all male dorsal surface and part of female, often ornate. Female depends on degree of engorgement, Haller's organ senses hosts Puvillus pad between claws enables crawling on smooth surfaces |
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Tick lifecycle
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Outdoor, usually diurnal, 1 nymphal stage
Feed 3 times (larva, nymph, adult) Stages loosely host specific, feed on small animals, adults on larger, maintenance hosts have blood needed to mature/mate/produce eggs, usually mate on the host, lay 1 batch eggs (2-15000), find host by questing/hunting Lays eggs - 6-legged larva - 8-legged nymph - adult |
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Hard tick feeding
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Hypostome held in by hooks, chelicerae secured by cement secreted by salivary glands
Larval/nymph/males grow as they feed Body distends without bursting, females may feed for days (needs much blood for 1 batch eggs, cuticle can stretch many times original size) Males come to host to mate and feed for sexual organs to mature |
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Nidicolous parasites
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Birds nests and burrows, animals which stay at site
Different stages on different animals Helps all stages get compatible hosts in physiologically suitable environment Few on one host |
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Multi-host
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2-3 different in one generation, larvae/nymph feed on wider range of smaller animals, adults on particular group of related hosts via hunting
Helps find sufficient compatible hosts to feed/mate in a suitable environment Specificity not absolute - hungry ticks attack to others, allows zoonotic infections to spread |
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Theileria transmission by ticks
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Kinetes: products of sexual reproduction in tick gut
Move to salivary glands, enter cells, develop into sporozoite with finite life when temperature rises, infective for vertebrate host Parasite develops in particular host cells Avoids cells producing cement for anchorage Moves to salivary gland in response to moulting hormone Synchronise infective stages with tick feeding/development |
