6.1 Dipteran Flies

Question 1

What are the following characteristics of INSECTS:
- body divisions (#)
- pairs of legs
- pairs of wings

Answer 1

• 3 body divisions
• 3 pairs of legs
• 2 pairs of wings (if they have)

Question 2

Describe the basic life cycle of diptera; what type of metamorphosis is this

Answer 2

Egg -> L1 -> Ln -> Pupa -> Adult

Complex metamorphosis

Question 3

Describe the antennae and mouthparts of the following suborders of Diptera:

1) Nematocera
2) Brachycera
3) Cyclorrhapha

Answer 3

1) Nematocera has piercing-sucking mouthparts and long segmented antennae

2) Brachycera has slicing mouthparts and stylate antennae

3) Cyclorrhapha have variable mouthparts and aristate antennae

Question 4

What are some examples of Diptera - Nematocera

Answer 4

mosquitos, gnats, midges, blackflies

Question 5

What can Nematoceran flies cause (3)

Answer 5

• worry
• anemia
• transmission of pathogens (biological vectors)

Question 6

What are two examples of Diptera - Brachycera

Answer 6

horse flies and deer flies

Question 7

What can Brachyceran flies cause

Answer 7

• worry
• painful bites
• transmit disease (mechanical vectors)

Question 8

What are some examples of Diptera - Cyclorrhapha

Answer 8

house flies, stable flies, face flies, flesh flies, warble flies, bot flies

Question 9

What type of mouthparts does the common housefly (Musca domestica) have

Answer 9

sponging-lapping (and remember it has an aristate antennae since its a Cyclorrhaphan Dipteran fly)

Question 10

Where do house flies (Musca domestica) lay their eggs? Where do they pupate? What do maggots eat?

Answer 10

In undisturbed cattle feces or rotting organic material; in soil; organic debris

Question 11

Why are house flies (Musca domestica) a problem

Answer 11

Significant mechanical vectors of pathogens; also annoying

Question 12

What type of mouthparts does the face fly (Musca autumnalis) have

Answer 12

Sponging-lapping

Question 13

Where does Musca autumnalis lay eggs? Where does it pupate? What do ADULTS feed on?

Answer 13

Undisturbed cattle feces; soil; eye, nose and mouth secretions

Question 14

What is unique about the preferred environment of face flies (Musca autumnalis)

Answer 14

Adults live on horses and cows outdoors ONLY and only come into buildings to overwinter

Question 15

Why are face flies a problem (3)

Answer 15

• annoying, cause worry
• mechanical vector for pathogens (Moraxella bovis)
• biological vector for eyeworms (Thelazia spp.)

Question 16

What type of mouthparts do horn flies (Haemotobia irritans) have? What other suborder of Dipteran flies have the same type of mouthparts?

Answer 16

Piercing-sucking; Nematocera

Question 17

What is the size of horn flies in comparison to house flies

Answer 17

1/2 size

Question 18

What is unique about the environment of adult horn flies (Haemotobia irritans)

Answer 18

Live almost constantly on hosts both inside and outside (the exception being leaving the host to lay eggs)

Question 19

Where does horn flies (Haemotobia irritans) lay eggs? Where does pupation occur? Where do pupae overwinter? Where do adults live?

Answer 19

Eggs laid in undisturbed cattle feces; pupation in soil; pupae overwinter in soil; adults live on the backs of cattle

Question 20

What problems do horn flies (Haemotobia irritans) cause (4)

Answer 20

• worry, annoyance
• reduces milk production and weight gain
• blood loss
• biological vector of a filarial nematode (Stephanofilaria stilesi)

Question 21

What type of mouthpart does stable flies (Stomoxys calcitrans) have

Answer 21

bayonet-shaped

Question 22

Where does Stomoxys calcitrans (Stable fly) lay eggs? Where do maggots live? Where is pupation?

Answer 22

Eggs laid in decaying vegetation; maggots in damp straw; pupation in soil (overwinter in soil)

Question 23

What is the significance of stable flies (Stomoxys calcitrans) (3)

Answer 23

• worry and annoyance
• reduced milk production and weight gain
• intermediate host for Habronema (nematode)

Question 24

How can we control muscid flies (house flies, face flies, horn flies, stable flies) through the environment

Answer 24

1) Timely removal of manure
2) Removal of sites with rotting vegetation/wet decomposition
3) Proper draining to prevent standing water and muck

Question 25

How can we control muscid flies through medication/treatment

Answer 25

Insecticides (OPs or botanicals)

Question 26

What is unique about the appearance of Melophagus ovinus (Sheep keds) (3)

Answer 26

NO WINGS on the fly, flattened dorsoventrally, hairy and leathery

Question 27

How does Melphagus ovinus get around having no wings (in terms of lifecycle)?

Answer 27

Adult females lay mature larvae that pupate immediately (spin cocoons right away)

Question 28

What is the significance of Melohagus ovinus (Sheep keds) (3)

Answer 28

- blood loss - irritation - damage to the wool (rubbing, staining)

Question 29

When are sheep keds typically an issue and why

Answer 29

Winter -> indoors, long wool, crowding of animals to facilitate transmission

Question 30

What are some agents of myiasis

Answer 30

- sarcophagids (flesh flies) - calliphorids (blow flies) - bot flies - warble flies

Question 31

what is the relative size of flesh flies and blow flies in comparison to house flies

Answer 31

flesh flies and blow flies are larger than house flies

Question 32

Where do sarcophagids (flesh flies) and calliphorids (blow flies) lay eggs? Where do larvae develop? Where does pupation occur?

Answer 32

Lay eggs on or near wounds, carcasses, soiled skin/wool; larvae develop in the same site; pupation occurs off of the host

Question 33

What are some predisposing causes to fly strike/wool strike caused by sarcophagids and calliphorids

Answer 33

- open, putrefying wounds - decaying wool from moisture, urine, uterine discharge, diarrhea, etc. - diarrhea from intestinal parasitoses

Question 34

What are some problems with sarcophagids and calliphorids (4)

Answer 34

- toxemia from decaying flesh - invasion of normal tissues - migration into underlying skin and mm - sheep kick and bite at the area

Question 35

How should you treat fly strike caused by sarcophagids and calliphorids

Answer 35

shear away the area, physically remove visible maggots, apply insecticides, antibiotics for secondary infections if necessary

Question 36

What species are affected by the following types of flies: - warble fly (grubs) - nasal bot fly - rodent and rabbit bot fly - stomach bot fly

Answer 36

warble fly (grubs): cattle, rarely horses (Hypoderma spp.) nasal bot fly: sheep rodent and rabbit bot fly: small animals (Cuterebrae spp.) stomach bot fly: horses (Gasterophilus spp.)

Question 37

What are unique features of adult bot flies

Answer 37

adults do not feed; they are bee-like

Question 38

What are the two types of warble flies (cattle grub)? Where do they overwinter?

Answer 38

Hypoderma bovis: in the spinal canal or epidural fat Hypoderma lineatum: in esophageal connective tissue

Question 39

Do hypoderma spp. aka cattle grub aka warble flies cause OBLIGATE or FACULTATIVE myiasis

Answer 39

obligate

Question 40

Describe the life cycle of hypoderma spp. aka warble flies aka. cattle grub

Answer 40

eggs laid on legs of cattle -> larvae penetrate skin -> larvae migrate to their overwintering site by December -> larvae migrate to the back after about 3 months (Feb-April) -> larve produce subcutaneous cysts in the back called warble -> larvae mature and drop out of the wound -> pupation in the environment

Question 41

what are some problems caused by hypoderma spp. aka cattle grub aka. warble flies

Answer 41

1) holes in the hide can reduce the value 2) cannot ride horses if they warble in the saddle area 3) reduced production due to energy expenditure in the fall from oviposition

Question 42

how do the larvae of cuterebra spp. aka rodent and rabbit bots differ from hypoderma spp. aka cattle grub aka warble flies

Answer 42

the cuterebrae larvae have little spines

Question 43

does cuterebae cause FACULTATIVE or OBLIGATE myiasis

Answer 43

obligate

Question 44

what is the life cycle of Cuterebrae spp.

Answer 44

eggs are laid near burrow openings -> larvae enter the host through the mouth or nose -> larvae migrate to the skin and cut a breathing hole -> larva mature from the hole and drop to the ground when mature -> pupation on the ground -> overwintering as pupae -> adults mate and lay eggs the following year

Question 45

what are some problems caused by cuterebrae spp.

Answer 45

cysts, rarely larvae enter the CNS

Question 46

how do you treat cuterebae (4)

Answer 46

physically remove the bot; debride cyst contents; anti-inflammatory/anti-biotics; systemic treatment if severe

Question 47

what type of stomach bots are most common?

Answer 47

Gasterophilus intestinalis

Question 48

do Gasterophilus spp aka stomach bots cause FACULTATIVE or OBLIGATE myiasis

Answer 48

obligate

Question 49

what is the life cycle of gasterophilus spp.

Answer 49

eggs laid on the legs -> oral migration -> larvae swallowed -> overwinter in stomach -> larvae pass out with the feces when mature

Question 50

what are the problems caused by Gasterophilus spp.

Answer 50

usually asymptomatic but can cause stomach lesions, rarely perforations causing abscesses and peritonitis

Question 51

what are the two types of lice? how do you tell them apart? what does each feed on? what is the relative motility of each? Where would you find each?

Answer 51

Anoplura (sucking) and Mallophaga (chewing); Anoplura has a narrow head relative to the rest of the body whereas Mallophaga is wide; Anoplura feed largely on blood whereas Mallophaga feed on skin, hair, feather secretions; Anoplura found in protected areas of the host whereas Mallophaga are motile so can be found in a variety of locations on the host, typically in the underarm

Question 52

What is the pathogen transmitted by the following BIOLOGICAL vectors: - Musca domestica: - Musca autumnalis: - Stomoxys calcitrans - Haemotobia irritans

Answer 52

Musca domestica: stomach nematodes of horses (Habronema, Draschia megastoma) Musca autumnalis: eyeworm (Thelazia) Stable flies: stomach nematodes of horses (Habronema) Haemotobia irritans: filarial nematode (Stephanofilaria stelesi)