Plant-Herbivore Interactions

Question 1

herbivory

Answer 1

consumption of all or part of a living plant by an animal

Question 2

______ of all macroscopic animal species are herbivores

Answer 2

25%

Question 3

compensation

Answer 3

plants grow enough to replace losses to herbivory

Question 4

overcompensation

Answer 4

some plants grow more than simple loss replacement in response to herbivory

Question 5

tissue loss to herbivory most commonly _________ of primary productivity

Answer 5

0-20%

Question 6

Physical plant defenses agianst herbivores

Answer 6

prevent or slow consumption
increase herbivore vunerabilities

Question 7

Chemical plant defenses against herbivory

Answer 7

toxins, repellents, growth inhibitors, abortions
reduce digestibility and egg production
make animals more susceptible to predators

Question 8

chemical defense in seed examples

Answer 8

cyanide in almonds
white oak has few chemical defenses, so they are eaten more than red oaks

Question 9

example of defense mutualisms

Answer 9

acadia tree and ants

Question 10

generalist herbivore

Answer 10

may increase diversity by feeding competitive dominants (eat most abundant species)

Question 11

specialist herbivore

Answer 11

effect depends on which plant species is the target (eating dominant species may help, eating subordinate species reinforces dominant species)

Question 12

what inflences the effect of grazing effects?

Answer 12

palatability of dominant species
productivity of system
history of grazing
spatial patterning of grazing

Question 13

bottom up process

Answer 13

plants control herbivores because they are bad food

Question 14

top down herbivores

Answer 14

predator limits prey population sizes

Question 15

removing predators can cause….

Answer 15

herbivore population explosions
depression of plant productivity when plants are unable to compensate for tissue loss
long term shift in plant species

Question 16

selective pressures involving herbivory

Answer 16

to defend
to eat, even if food is heavily defended
defended food may be open resource for which there is little competition

Question 17

key aspects of plant-herbivore interactions to evolutionary arms race

Answer 17

type and #of defenses
timing of defense
specialization of defence

Question 18

constitutive (static) defense

Answer 18

always on, requires little energy maintenance, likely to drive rapid selection in herbivores

Question 19

induced (mobile) defense

Answer 19

initaited upon attack and requires continual energy input when on

Question 20

generalist herbivores ate _____ on induced plants

Answer 20

less

Question 21

specialist herbivores ______ induced plants

Answer 21

preferred

Question 22

structural defenses of a herbivore

Answer 22

prevent toxins from interfering
moves toxin outside of body
toxin stays active to tolerance aquired
can be repurposed as an anti-predator defenses

Question 23

behavioral defenses of herbivores

Answer 23

feeding - avoiding cutting veins or eat low toxicity tissues
egg laying - lay eggs on low-toxicity plants

Question 24

biochemical defenses of herbivores

Answer 24

ability to detoxifiy defensive compounds

Question 25

host-race formation

Answer 25

genetically distinct subpopulations of a herbivore species that utilize different plant hosts

Question 26

steps to host race formation

Answer 26

mutations that allow changes in host preferance
assortive mating

Question 27

assortative mating

Answer 27

mating a function of host plant preferance