Multitrophic Interactions

Question 1

explain Trophic levels

Answer 1

• Fundamentally divided between producers and consumers
• Energy passes through each level
• Less energy is available at each level
• Consequently, the total biomass rapidly falls when climbing trophic levels

Question 2

define trophic interactions

Answer 2

Anything done by members of one trophic level that affects members of another

Question 3

define herbivory

Answer 3

• Second trophic level
• Take advantage of enormous level of resources offered by plants
• Dominated by insects

Question 4

define predation

Answer 4

• Hunt and kill second trophic level and above
• Predators are often generalists, but some are specialists

Question 5

define parasitism

Answer 5

• Similar to predation, but does not immediately kill host
• Extremely successful, accounting for much as half of all species

Question 6

define parasitoids

Answer 6

• Either a subset of or adjacent to parasitism
• Key difference: host almost always die
• Include upwards of 100,000 insect species, primarily wasps and flies

Question 7

explain how trophic levels are fluid

Answer 7

• Many organisms, including insects, change trophic levels or multiple
• This can create complex interactions bc they are context dependent

Question 8

trophic levels are fluid - examples

Answer 8

• most parasitoids and all omnivores
• They may drop down or go up a trophic level when they become adults
• They may also feed on other insects when given the chance

Question 9

how do organisms Finding prey

Answer 9

Predators and parasitoids can directly search for prey

Question 10

finding prey - primary signals

Answer 10

• Visual
• Chemical

Question 11

finding prey - problem

Answer 11

• a pairwise approach
• prey species are under selection to hide

Question 12

finding prey: problem - how do prey hide

Answer 12

• Cryptic coloration
• Minimal chemical signature – lower their chemical signature, causes them to smell less

Question 13

How do pairwise interactions expand?

Answer 13

they expand when something happens at one trophic level affects others

Question 14

pairwise interactions expanding - examples

Answer 14

• Exotic plants outcompete natives, caterpillars starve, caterpillar predators decline
• Parasitoids reduce herbivore population, increasing plant growth or reproduction
• Plant defensive compounds may harm predators of herbivores on the plant

Question 15

what are plant volatiles

Answer 15

• Organic compounds with a high vapor pressure and low water solubility
• they readily evaporate
• Parasitoids (and some predators) can detect this

Question 16

What promotes production of plant volatiles?

Answer 16

• many things
• particulary damage

Question 17

what are herbivore induced plant volatiles (HIPVs) are triggered by

Answer 17

• Damage-associated molecular patterns (DAMPs)
• Herbivore-associated molecular patters (HAMPs)

Question 18

explain kin selection regarding plant volatiles

Answer 18

• Volatiles are detected by nearby plants that are relatives, and they prepare for defense
• Plants may have evolved volatiles to call for help

Question 19

what are hyperparasitoids

Answer 19

• they target other parasitoids
• they wait until an insect is parasitized and then lay eggs within the parasitoid’s eggs
• Constitute higher trophic level
• they are typically specialists and have a narrow range of hosts

Question 20

why do species want to be in a mutualism with ants

Answer 20

• Ants are good friends and dangerous enemies
• There are a lot of them
• Colonies persistent
• Ants are dominant predators in many systems
• Few predators want to mess with ants

Question 21

why may an ant betray their mutualism partner

Answer 21

• Ants are protecting for a reward
• If another mutualist have a better reward, they will betray their current mutualist

Question 22

How do multitrophic interactions shape communities

Answer 22

• Populations experience top-down and bottom-up pressure
• Many organisms require mutualists
• Dense networks are often required to maintain stability

Question 23

explain Multitrophic interactions in the Anthropocene

Answer 23

• Phenology is altered
• Non-indigenous species are introduce to ecosystems
• Simplification of habitats and networks

Question 24

multitrophic interactions in the Anthropocene - definition phenology

Answer 24

• cyclic timing of events
• Animals/insects have their own period to do things, climate change changes phenology

Question 25

What does the changes in multitorphic interactions mean for conservation

Answer 25

- Species do not function in a vacuum - We need to consider ecosystems, not just individual species - Insects (and plants) are essential to multitrophic interactions