Diptera and Hemiptera Entomology

Question 1

what are diptera

Answer 1

• One pair of functional wings
• Hindwings modified to form halteres
• Flies, mosquitoes, midges, gnats

Question 2

diptera - Wings

Answer 2

• Single pair of membranous front wings
• instead of hind wings, they have halteres

Question 3

diptera: wings - what are halteres

Answer 3

• reduced hind wings that form a pair of balancing organs
• beat at the same frequency as wings, but out of phase

Question 4

dipera: wings - what do halteres allow the insect to do

Answer 4

• Hover
• Fly backwards
• 360 degree turns
• Upside down flight and landing

Question 5

explain the Indirect flight muscles

Answer 5

• Indirect flight muscles attach to thorax, not wings
• Muscles flex thorax, thorax flaps wings
• Asynchronous
• Enables high wingbeat frequency

Question 6

indirect flight muscles - asynchronous

Answer 6

multiple contractions from single nerve impulse

Question 7

indirect flight muscles - Enables high wingbeat frequency

Answer 7

can be higher than fastest possible neural re-polarization rate

Question 8

diptera - what are some of their niches

Answer 8

• Pollinators
• Predators
• Blood feeders
• Herbivores
• Parasitoids
• Scavengers

Question 9

diptera - explain their mouthparts

Answer 9

May be:
- sponging (e.g., housefly)
- Biting (e.g., horsefly)
- Piercing sucking (e.g., mosquito)

Question 10

diptera - Pollinators

Answer 10

• Bee flies and hoverflies are pollinators
• both feed on nectar as adults
• but as larvae, bee flies are parasitoids and hoverflies are predators

Question 11

diperta - Predators

Answer 11

• Robberfly kills honeybee with piercing-sucking mouthparts
• fly mimics a bumblebee

Question 12

diptera - Blood feeders

Answer 12

• Not just mosquitoes, diptera may use biting, rather than piercing/sucking mouthparts
• Horsefly feeds from pool of blood
• Sandfly feeds on human blood

Question 13

diptera - scavengers

Answer 13

• Along with Cleopatra, flies are the most important order for consuming feces and carrion
• Progression of species on carrion is the basis for forensic entomology

Question 14

how does the botfly lay eggs

Answer 14

1) female catches mosquito in flight, attaches eggs
2) mosquito finds mammal host; body heat causes 1st instar larvae to drop from eggs onto mammal
3) larvae burrows into host, feeds on blood
4) when done feeding, larva emerges from host to pupate in soil

Question 15

explain the three broad categories of insect attacks

Answer 15

• Direct harm: venoms and other chemical defenses
• Allergic reactions, often in conjunction with the above
• Vectors of other disease-causing organisms

Question 16

When insects attack humans – tissue feeders

Answer 16

Myiasis: when fly maggots develop in living flesh, often exploiting existing injury (e.g., infected mosquito or tick bite)

Question 17

when insects attack humans - explain Maggot therapy

Answer 17

some maggots eat only dead tissue – put them on a nasty wound, they clean it by consuming the dead, infected parts

Question 18

When insects attack huamns– blood feeders

Answer 18

• Blood feeders have evolved in multiple orders
• Generally, the direct effects of these are irritating (itches, potential infection) but not life-threatening
• The serious effects come from parasites vectored by insects (except bedbugs)

Question 19

when insects attack humans: blood feeders - where have blood feeders evolved

Answer 19

• Hemiptera
• Reduviidea (subfamily Triatominae)- kissing bugs
• Cimicidae – bedbugs
• Pthiraptera – lice
• Diptera has many groups, mosquitoes most prominent
• Also: Siphonaptera – the fleas
• Also: Ticks (not insects), but prominent arthropod blood feeders

Question 20

diptera - explain malaria

Answer 20

• Malaria is a mosquito-borne infectious disease caused by the parasite Plasmodium falciparum
• Malaria is transmitted by the infected female mosquito Anopheles
• Remember, piercing sucking mouthparts – the dirty syringes of nature

Question 21

what are the Siphonaptera

Answer 21

• fleas
• wingless
• Can use natural elasticity of cuticle for huge jumps
• All ectoparasites, mostly mammals (few birds)
• Piercing sucking mouthparts
• Laterally flattened (i.e., ‘skinny’), mostly ectoparasites are dorso-ventrally flattened

Question 22

siphonaptera - explain the black death

Answer 22

• Fleas are the vector, bacteria Yersinia pestis the pathogen
• Primarily flea-rodent disease, but when fleas can’t find rats to bite, they go for humans
• Bacteria infects flea, blocks the gut so that flea regurgitates when it feeds
• Will thus regurgitate bacteria into new hosts when feeding
• Bc flea cant get food, its starving, and feeds more and more aggressive