Sand Flies and Biting Midges Flashcards
- What is the name “Sand fly” commonly used to describe?
o Biting diptera
- What are ceratopogonidae?
o Midges (Diptera)
- What are simuliidae?
o Black flies (Diptera)
- What are Psychodidae?
o Sandflies (Diptera)
- What is the classification of sand flies?
o Order: Diptera
o Sub-order: Nematocera
o Family: Psychodidae
o Subfamily: Phlebotominae
- How do phlebotominae maneuver?
o Cryptic species
o Poor fliers
o Fly close to ground and walls
- What are the basic characteristics of sandflies that distinguish them from true flies?
o 1.5 to 3.5 mm in length
o Large black eyes
o Dense hair covers
o Long, stilt like legs
o When resting, the sand fly will have its wings in a V shape, at a 45-degree angle
o Pigmented pattern on the wings
- How are the species of sandflies split?
o Whether they are found in the old world (Asia, Europe, Africa) or the new world (America, Caribbean, South America)
- What is the distribution of sandflies?
o Locations that maintain a temperature above 15.6 degrees Celsius for at least 3 months
o Sandflies require both humidity and temperature to develop
- What kind of habitats do sandflies prefer?
o Indoors
o Cracks
o Holes
o Termite mounds
o Poultry houses
o Animal burrows
o Caves
o Latrines
o Leaf litter
- How long is the life cycle of the sandfly?
o Pretty long, it takes about 1 to 3 months
- What kind of life cycle do sandflies have?
o Complete metamorphosis-holometabolous
- What are the life cycle stages of the sandfly?
o Egg
o Larvae
o Pupae
o Adult
- Why is the life cycle of the sandfly different from the mosquito?
o The life stages of the sandfly are all terrestrial, unlike the mosquito which must develop in water during the immature stage of life
o Different from other nematoceran flies (mosquitos, crane flies, gnats, black flies, midges)
o The generation time also takes months instead of weeks
- How many eggs do sandflies lay in a batch?
o 30 to 70 eggs are laid individually or in groups of 2 to 3
- What are the characteristics of sandfly eggs?
o Small (0.3 to 0.4 mm)
o Ovoid shape
o Brown or black
- Since sandfly eggs are not laid in water, does that mean that eggs can withstand desiccation?
o No, the eggs require a high humidity to develop. Therefore, they cannot withstand desiccation
- What are the characteristics of sandfly larvae?
o 3 to 6 mm long
o White or grey
o 12 segments
o Well defined black head
o Small mandibles
o Pseudopods (fake foot) on the abdominal segments
o Thick bristles with feathered stems
- How many stages do sandfly larvae have?
o 4 that takes about 20 to 30 days to develop
- How does the winter affect sandfly larvae?
o Sandflies will overwinter and enter a dormant stage
- What are the characteristics of sandfly pupa?
o 2.6 mm in length
o Larval skin will remain attached to the end of the pupa
- What is the significance of the larval skin still attached to the pupa?
o The skin, along with caudal bristles aid in the recognition of phlebotomine pupa
- at what time of day adult sandflies emerge from the pupa stage?
o During darkness, just before dawn
- What are the characteristics of adult sandflies?
o 1.5 to 3.5 mm in length
o Hairy body
o The wings are held at 40 degrees when resting or blood-feeding, in a V-shape
o Long legs
- How does the sand fly feed?
o So, we know that it feeds through blood, therefore, it has a proboscis to feed
- T/F. Only the female sandfly bites.
o True
- What are the characteristics of the mouthpart for the sandfly?
o Short
o Inconspicuous
o Sucks blood
o Females:
Six broad stylets held in the fleshy labium (labrum, paired mandibles, maxillae, and hypopharynx)
Mandible and maxillae are toothed distally
o Five segmented palps with an array of sensory setae
- How do sandflies disperse?
o Sandflies are weak fliers, flying (or hopping) close to the ground
- When do the sandflies feed?
o At dusk of night when the temperatures lower and humidity rises
- When will sandflies bite during the day?
o In dark or shaded areas
- Where are the habitats of sandflies?
o Adults will have live near the larval sites, near a host
o The range remains near what is needed for the life cycle such as resting, feeding, and oviposition
- What kind of sensory cues do sandflies use?
o Long- and short-range cues
o Females will release a feeding pheromone from the palps to attract other females
- What kind of host feeder are sandflies?
o Opportunistic feeder
- Is the main diet of the sandfly blood?
o No, both male and females feed on sugar meals for energy
o It is just the female that feeds on blood for egg production (every 5 to 6 days)
- What can influence the feeding activity of the sandfly?
o Temperature
o Humidity
o Air movement
- What type of feeding patterns do sandflies have?
o Primarily exophagic
o The vectors that transmit leishmaniasis are endophagic
- Compare the mating habits of the sandfly to the mosquito.
o The sandfly, unlike most dipteran vectors, do not swarm. Instead, the males will aggregate on a location and conduct a courtship dance while releasing sex pheromones (lekking) to attract females.
o When the female lands, they may mate multiple times while feeding on blood
- When looking for oviposition sites, what do female sandflies look for?
o Female sandflies will analyze the temperature, humidity, UV exposure, and available locations
o Oviposition females prefer laying eggs on substrates that have already been used or are full of larvae over fresh substrates
- How do female sandflies know that the area they are about to lay eggs at has been used by other female sandflies?
o When a female lays eggs it will deposit a pheromone, dodecanoic acid, on oviposited eggs to attract other eggs
- How long is the gonotrophic cycle of sandflies?
o 5 to 8 days
- How many blood meals does a female sandfly require to complete the gonotrophic cycle?
o One or more per cycle
- How many times can a female undergo the gonotrophic cycle?
o Multiple cycle where 4 is common in the lifespan of sandfly
- What disease are of most concern from sandflies?
o Leishmaniasis, a protozoan disease where 70 species have been known to carry it
o Some carry Phlebovirus and other arboviruses
o One vector is known to carry Carrion’s disease
- What are the only natural vectors of Leishmania species?
o Phlebotomine sandflies
- For Leishmaniasis to progress in the host, what interactions are required?
o The parasite and the host immune system
- What are the clinical forms of Leishmaniasis?
o Cutaneous
o Mucocutaneous
o Visceral (most fatal)
- What is the mode of transmission for leishmaniasis?
o Cyclopropagative, meaning it develops in the vector and it multiplies
- What is the route of transmission of leishmaniasis?
o Regurgitation
- What is the transmission prevention method for leishmania?
o This is the relationship between the host and the vector
o The prevention methods include controlling animal reservoirs, IRS, repellents, and education
o For the vector, controls include IVM through insecticides and habitat control
- What is the pathogenicity prevention method for leishmania?
o This is the relationship between the vector and pathogen which is controlled by GMO
- What is the susceptibility prevention method for Leishmania?
o This is the relationship between the pathogen and the host
o The prevention method is vaccines
- Of the Ceratopogonidae, which species feed on humans?
o Culicoides
o Leptocanops
o Forcipomyia
o Austroconops
- What are the common names of ceratopogonidae?
o No-see ums
o Punkies
o Sand gnats
o Black gnats
o Flying teeth
- What is the classification of the ceratopogonidae?
o Order: Diptera
o Sub-order: Nematocera
o Family: Ceratopogonidae
- In the ceratopogonidae, which vector are we most concerned about medically?
o Culicoides
- What characteristics distinguish biting midges from other true flies?
o 2 to 4 mm in length
o Hanging female mouthpart
o Venation on membranous wings
o Brown and white spots on the wings
o Wing rest over the body
o Short fore legs
- What is the global distribution of the culicoides?
o Culicoides inhabit all large land masses except New Zealand, Iceland, and Hawaii
- What kind of life cycle do the culicoides have?
o Complete metamorphosis holometabolous
- What are the four stages of the life cycle in the culicoides?
o Egg
o Larvae
o Pupae
o Adult
- How long does the life cycle last for the biting midge?
o 14 to 42 days
o The life cycle may last months if climate conditions are poor requiring overwintering
- Where do biting midges lay eggs?
o In moist soil
o Immature biting midges require aquatic or semi-aquatic environments so eggs cannot withstand drying out
- How many eggs can a biting midge lay in a single batch?
o Up to 450
- How many batches may biting midges lay?
o Up to 7 in their lifetime
- During the life cycle, what do the larval instars and pupal stage of the biting midge require?
o Moisture
- What happens if during the life cycle climate conditions are poor?
o The larvae may overwinter/diapause
- Where will you find immature biting midges?
o Aquatic or semi-aquatic environments
o Fresh mud
o Salt or brackish water
o Tree holes
o Damp areas with decaying matter
o Rotting fruit
o Plant holders
- What are the characteristics of biting midge larvae?
o Worm-like
o Creamy white
o 2 to 5 mm long
o The first instar has a spine-bearing proleg
- How many instars do biting midge larvae have?
o 4
- T/F. Larvae of biting midges are strictly aquatic.
o False, larvae are not strictly aquatic or terrestrial. Remember, they can require a semi-aquatic environment. But they do require water, air, and food.
- What are the characteristics of the adult biting midge?
o The thorax extends slightly over the head
o The abdomen has 9 segments and is tapered at the end
- What is the activity of the biting midge?
o Crepuscular, meaning they are active at twilight, dawn or dusk
- Where do biting midges tend to forage?
o Around larval habitats
- What do both male and female biting midges feed on?
o Plant juices and sugar secretions
- What do only the female biting midge feed on?
o Blood
- How do biting midges feed?
o Telmophagy, meaning that biting midges feed on a pool of blood (hence “biting”)
- What hosts do female biting midges prefer to feed on?
o Mammals, birds, reptiles, amphibians
o The biting midges are host specific, but are opportunistic feeders
- What are the feeding and location behaviors of the biting midge?
o Endophagic
o Endophilic
o Exophagic
o Exophilic behaviors
- What drives the behavior of biting midges?
o Whether the biting midge prefers inside or outside is dependent on the temperature
- What are the mating behaviors of biting midges?
o The females, like the mosquitos, will fly into a swarm of males. The males will attach to the female, end to end, to mate
o There are some species that will go to a host where females are feeding. The males will then use a sex attractant that will lure the female to mate after feeding
- What kind of diseases can biting midges (culicoides) transmit?
o Viruses
Oropouche
Crimean-Congo hemorrhagic fever
Dugbe virus
Rift valley fever
Blue tongue virus
o Protozoans
o Filarial nematodes
Cavity filariasis
Mild dermatitis
o There are no known bacterial pathogens that can be transmitted by culicoides
- Where does blue virus occur?
o On livestock
o This is of medical importance because it can be a huge financial loss to farmers
- What methods are used to prevent transmission of Oropouche?
o This is the relationship between the host and the vector
o Methods to reduce transmission include repellents, education, and PPE
o To deter the vector, IVM methods such as insecticides and habitat control are used
- What methods are used to prevent pathogenicity of Oropouche virus?
o This is the relationship between the vector and the pathogen
o Sterile insect technique (SIT) or Incompatibility Insect technique (IIT) which create a lethal male dominant (self-killing sterile) population or genetic modification to reduce the population
