Diptera Flashcards
General characteristics
True flies
- 2 winged
- balancing halteres
- complex metamorphosis
Importance of diptera
Larvae of some species cause myiasis (larval infestation)
- adults of others are blood suckers
What determines if the larvae or adults are parasitic?
Mouthparts
- lapping: adults not parasitic
- piercing: adults are parasitic, role in disease transmission
- combo: horsefly
- nonfunctional: larvae are parasitic
Brachycera
- myiasis flies (bot, blow, fesh, muscid)
- stable flies
- horn flies
- keds
- horse and deer flies
Nematocera
- mosquitoes
- biting midges
- black flies
- sand flies
Brachycera breed in _______
Decaying material
- 3 larval instars
- morphology of spiracles
Myiasis
Parasitism by fly larvae
- may be living or necrotic tissue
- obligate, facultative, accidental
- GI and cutaneous are common sites (also have urogenital, ocular)
Oestridae
Bot flies
- highly host specific
- adults non-parasitic
- aberrant hosts
Gasterophilinae
Horse bots
- G. intestinalis (most common)
- G. nasalis
- G. hemorrhoidali (least common)
- hatching induced by environmental cues, larvae migrate to specific host location
Gasterophilus intestinalis
- eggs: legs, shoulders
- LI: tongue epithelium, tooth pockets
- L2: tooth pockets, stomach wall
- L3: nonglandular portion of stomach
Gasterophilus nasalis
- eggs: intermandibular region
- L3: pylorus and duodenum
Hasterophilus haemorrhoidalis
- eggs: lips
- L3: duodenum and rectum
Can you find L3 stages of horse bots in the stool?
No!
Oestrus ovis
Sheep bots
- subclinical infestation
- fly will deposit first larval stage, not the egg! on the nose of the sheep
Cuterebra
Rodent and squirrel bots
- also infest rabbits, dogs, cats, etc
- adults lay eggs in host habitat, larvae get onto host fur and enter natural openings, migrate to subq locations
Hypoderma
Cattle bots
- timing of treatment is critical: toxins from dead/dying larvae cause adverse rxns
- treat immediately after fly activity stops, NOT in winter!
Hypoderma lineatum vs hypoterma bovis
H. lineatum - eggs in rows on legs - LI: esophagus - L2/L3: SQ tissue on back - late spring/early summer H. bovis - eggs: singly on legs - L1: spinal cord - L2?L3: SQ tissue on back - late summer
Calliphoridae
Blow flies
- adults have a metallic color!!
- lay eggs/larvae in tissue
- faultative parasites (mostly)
- -> live tissue (obligatory, primary myiasis)
- -> dead tissue (facultative) secondary myiasis
Screwworms
Primary: Cochilomyia hominivorax (reportable!)
–> eggs immediately infect host, even with intact skin
Secondary: Chocliomyia macellaria
–> more common in US, will land on necrotic tissue
Sarcophagidae
Flesh flies
- larger than house flies
- eggs laid in carrion, feces, wounds
- cause facultative myiasis
- useful in forensic entomology
Muscidae
Musca domestica: house fly
- adults are nuisance
- pathogen transmission via mechanical (bacteria) or biological (nematodes)
Musca autumnalis
Face fly
- cattle, horses
- feed on ocular, nasal discharge
- pathogen transmission
- -> nematode Thelazia
- larvae rarely associated with cutaneous myiasis
Cutaneous myiasis
Larval infestation from blow flies, flesh flies, rarely muscid flies
- foul smelling, depressed or restless, decreased weight gain
- severe infestations are fatal
Muscidae are muscid flies that are _______ as adults
Blood feeders!
- both male and female are blood feeder
Stomoxys vs Haematobia
Stomoxy (stable flies) - quick feeder, house fly with proboscis - nuisance, decrease ADG - breed in manure w/feed Haematobia (horn flies) - slow feeder - house fly - less ADG - breed in manure only
Stomoxys calcitrans
Non-myiasis muscid fly
- dairy cattle, dogs, horses, humans
- biological vector for nematode and other pathogens
Haematobia irritans
Non-myiasis muscid fly
- beef cattle, horses
- biological vector for nematode
Control for muscidae
- sanitation
- regular spraying of premises
- fly baits, resin, strips, ear tags, UV traps
Keds
Hoppoboscidae (louse flies)
- non host specific
- dorsoventrally flattened
- piercing/sucking mouthparts
- larvae stay in female abdomen until ready to pupate
Melophagus ovinus
Transfer via direct contact
- entire life cycle on host
- Trypanosoma melophagium (sheep is a reservoir)
Lipoptena cervi
Wings break off (resemble lice)
Tabanidae
Horseflies and deerflies
- stout-bodied, vary in size
- only adult females require blood meal
- eggs glued to vegetation overhanging water –> L3 carnivorous
Greenheads
Tabanus spp. (horse flies)
Chrysops
Deer flies
- larger than house fly
- banded wings
- larvae feed on organic matter is soil
Nematocera
Delicate flies
- segmented antennae
- semi-aquatic to aquatic breeding sites
- only adult females are blood feeders!
- serve as vectors
Culicidae
Mosquitoes
- long antennae
- eggs laid on soil or water
- -> 4 larval instars, pupae require water, are motile
Veterinary importance of mosquitoes
Direct disease - nuisance, allergies - blood loss Indirect disease: vectors - nematodes, protozans, viruses Medical importance: #1 vector of human importance
What do mosquitoes feed upon
Nearly any animal that is not aquatic
- serve as food for fish, tadpoles, bats
- adults contribute to pollination
Culicidae life cycle
Complete in 4 days to >1 month
- eggs laid in area that will become wet or on existing wet surface –> larvae wigglers have siphon to take in air –> non feeding pupa also use siphon –> adult emerges from pupa
Standing water breeders
- eggs need water
- Anopheles quadrimaculatus (common malaria mosquito)
- Culex quinquefasciatus (southern house mosquito)
Floodwater mosquitoes
Eggs in moist soil or artificial containers
- hatch in rain or flood
- Aedes vexans (inland floodwater)
- Aedes sollicitans (eastern saltmarsh)
Anopheles quadrimaculatus
Most common in eastern US
- feed on big mammals
- vector for agents of malaria, heartworm!
Which species of Culicidae are native to US?
Culex quinquefasciatus (southern states)
- heartworm, encephalitis
Aedes vexans
- heartworm, encephalitis
Which species of Culicidae are introduced to US?
Aedes aegypti - Africa native - Yellow fever, dengue, chikungunya Aedes albopictus - Asia native - yellow fever, dengue, chikungunya
Culicidae integrated pest management
- biological
- mechanical: drain swamps, bed nets
- chemical: larvicides, adulticides, repellants
- green nanotechnology
Biting midges
Ceratopogonidae
- Culicoides spp
- short flight range, active at dawn and dusk
- painful bites!
Biting midges as vectors
Viruses - bluetongue - epizootic hemorrhagic disease Nematodes - Onchocercea Protozoa - Avain hemosporidians - Haemoproteus, Leucocytozoon
Black flies
Simulium
- small, stout bodied, hump on thorax, short antennae
- breed only in running water
- daytime biters
Black flies as vectors
Viruses - vesicular stomatitis Nematodes - Onchocerca Protozoa - Leucocytozoon
Sand flies
Psychodidae
- Lutzomyia spp
- small dull colored (hairy furry)
- nocturnal, rest in moist places in the day
- short lived adults, weak fliers
Sand flies as vectors
Viruses
- vesticular stomatitis
Protozoa
- Leishmania
Reduviid bugs
Kissing bugs
- vector: Trypanosoma cruzi
Bed bugs
Increasing population
- disease transmission not confirmed
- exsanguination in chickens
