8: Heil et al 2003

Question 1

why may symbioses be good to study in order to study what?

Answer 1

to study social evolution and food web structure

Question 2

in how many genera of angiosperms and ants have ant plant mutualisms evolved in?

Answer 2

over 100 genera

40

Question 3

what can be considered an important indirect defence?

Answer 3

ants attracted to plant derived food rewards

Question 4

what is a direct reward given by the plant?

Answer 4

EFN of food bodies

Question 5

what are 3 plant enemies and what may compete for EFN?

Answer 5

herbivores, leaf cutting ants, fungal pathogens

mites and ladybugs

Question 6

how can EFN secreting plant control the effectiveness of their defence?

Answer 6

control amount/quality of nectar secreted

Question 7

what are rates of herbivory like on ant free trees?

Answer 7

higher

Question 8

where should defence be concentrated on a plant?

Answer 8

parts most vulnerable with peak production coinciding with greatest risk herbivore attack

Question 9

what is the timing of EFN production specific to?

Answer 9

selection pressures on each different plant species

Question 10

what type of nectar do ants generally prefer?

Answer 10

those highly concentrated in amino acids

Question 11

what can an abundance of plant derived exudates shape and why?

Answer 11

food web structure

ants can evolve energetically costly prey foraging strategies

Question 12

what are 4 examples of nesting sites/domatia?

Answer 12

hollow stems, thorns, petioles, leaf pouches

Question 13

when is survival and reproduction increased?

Answer 13

if ants better protect host tree and if plants invest more in maintaining protective ant colony

Question 14

how may some ants gain external food sources?

Answer 14

gather pollen grains or fungal spores falling onto host

Question 15

give 6 costs of the symbiosis

Answer 15

• food rewards may have ecological costs to plant
• defence trait may attract enemies
• nesting space may limit ant colony size
• ants may push resource demands to a range where they become parasitic
• ants may manipulate plants to invest more in resources benefiting ant at cost to plant
• beetles can live and feed on ant inhabited trees without being attacked by ants

Question 16

how can ants protect despite their small body size?

Answer 16

focus attacks on vulnerable parts of attackers

Question 17

what sort of defence can some plants switch between?

Answer 17

from biotic to chemical defence

Question 18

how is defence made optimal?

Answer 18

concentrate plant defence on vulnerable parts of the plant where it is most required