Lecture 6

Question 1

parasitoid

Answer 1

parasitic while immature but free-living as an adult

Question 2

What distinguishes parasitoids from parasites?

Answer 2

Ultimately kills the host to complete its own life cycle (doesn’t occur in parasites)

Question 3

____ % of all described insect species are parasitoids

Answer 3

10%

Question 4

what portion of Hymenoptera species are parasitoids?

Answer 4

3/4

Question 5

what portion of Diptera & Coleoptera species are parasitoids?

Answer 5

1/4

Question 6

how many insect orders include parasitoids? & where how many have most of the diversity?

Answer 6

7

3

Question 7

what order includes the bulk of parasitoid diversity? & what are 3 ex?

Answer 7

Hymenoptera (most families of wasps are parasitoids)

ex: Braconid wasps
ex: ichneumonid wasps
ex: chalcid wasps

Question 8

braconid wasps attack what type of insects?

Answer 8

insects with holometabolous development

Question 9

what is likely the most diverse animal & insect family?

Answer 9

ichneumonid wasps of Hymenoptera

Question 10

what do ichneumonid wasps eat?

Answer 10

Attack broad range of insects

spiders

centipedes (not insects)

Question 11

chalcid wasps

Answer 11

super family

small

metallic

Question 12

what order are staphylinid beetles in?

Answer 12

coleoptera

Question 13

what is the largest animal family?

Answer 13

staphylinid beetles

Question 14

what are the 7 orders with parasitoids?

Answer 14

3 main: Hymenoptera, Diptera & Coleoptera

4 others: Lepidoptera, Trichoptera, Neuroptera, Strepsitera

Question 15

what is the 2nd largest family of flies?

Answer 15

tachinid flies

Question 16

who do tachinid flies attack?

Answer 16

generalists

attack caterpillar & sawflies

Question 17

ectoparasitoid

Answer 17

larval stage feeds from outside of host

Question 18

endoparasitoid

Answer 18

larval stage feeds from inside host

egg is implanted on the inside of the body & feeds on the inside of the host

Question 19

how do you determine the number of offspring produced per host?

Answer 19

depends on the size of the paraistoid compared to its host

Question 20

solitary parasitoid

Answer 20

one larvae develops on/in host

Question 21

gregarious parasitoid

Answer 21

multiple larvae develop in/on a single host

results form multiple eggs

Question 22

polyembryonic parasitoid

Answer 22

produce multiple offspring from a single egg

eggs undergo fission

Question 23

idiobiont

Answer 23

host growth stops at time of parasitism (as soon as host is parasitized, the host development stops)

mother injects venom immobilizing the host

primarily of ectoparasitoids or endoparasitoids of immobile phases

Question 24

koinobiont

Answer 24

host continues to feed, act normally & develop normally as parasitoids are developing within it

injections alter immune system

primarily endoparasitoids

parasitoid receives constant nutrition & protection

Question 25

parasitoids are only assoc with host during what stages?

Answer 25

egg

larval

Pupa

Question 26

primary parasitoid

Answer 26

attacks non-parasitoid host

Question 27

hyperparasitoid

Answer 27

attacks another parasitoid

Question 28

What forms of defense can help potential hosts to escape or otherwise reduce the impact of parasitoid activities? (3)

Answer 28

behavioural defenses

chemical defenses

immune responses

Question 29

behavioural responses (8)

Answer 29

o	Wriggling 
o	Aggregation 
o	Spitting 
o	Kicking 
o	Running 
o	Dropping 
o	Flying
o	Movement away from conspecifics

Question 30

chemical defense

Answer 30

ex: alarm pheromone release - invokes response in all other aphids in a colony

Question 31

when do immune responses occur?

Answer 31

if eggs are deposited into the hemolymph

Question 32

describe the process of when an immune response occurs?

Answer 32

hemocytes adhere to & form a capsule around the egg (of the parasitoid)

the capsule can melanize & suffocate the egg preventing it from hatching

Question 33

How do parasitoids overcome host defenses?

Answer 33

behavioural modification

specialized morphology

venom

polydna viruses

Question 34

what are some exs of behavioural modifications in hosts of parasitoids?

Answer 34

ex: parasitized caterpillars may actually increase consumption, thereby producing larger & more fecund parasitoids
ex: parasitized aphids move away from patches to the other side of leaves

Question 35

how do parasitoids have specialized morphology to overcome host defenses?

Answer 35

Laying eggs into host – highly modified ovipositors
Ex: parasitoid wasps have bits of metals to insert the eggs

Ovipositors can taste to ensure that they are injecting into the correct host

Question 36

how do parasitoids use their venom to overcome host defenses? (4)

Answer 36

paralytic activity

Disrupt hemocyte adhesion – increasing likelihood that the egg will hatch

Prevent host molting
Ectoparasitoid koinobionts
When a host molts it will shed the ectoparasitoid
May disrupt endocrine system & disrupt hormones important for molting

Severe metabolic alterations
Ex: make host more nutritious – make lipids available

Question 37

polydna virus

Answer 37

Integrated into wasp genomes

Replicates in wasp ovaries & integrates into host genome

Cause immune response breakdown upon injection into host – prevents host from responding to egg
Disrupts encapsulation
Prevents nutritive uptake

Breaks down immune response & makes host more nutritious at the same time