Mutualism - 18

Question 1

Define mutualism

Answer 1

an INTERSPECIFIC interaction that is beneficial to both species, in terms of costs and benefits for both species

Question 2

What are examples of benefits and services involved in mutualism

Answer 2

goods/benefits = food, nutrients, shelter
services/benefits = transport of gametes or offspring, protection from enemies

Question 3

Explain mutualism as mutual exploitation

Answer 3

natural selection doesn’t produce modifications for the good of others, but throughout nature, species take advantage and benefit from structures of others

Question 4

Define facultative mutualists vs. obligate mutualists

Answer 4

facultative = populations can persist without the mutualist
obligate = cannot survive without the other

Question 5

What is the interdependence continuum

Answer 5

provides examples of facultative and obligate mutualists and display increasing interdependence from facultative to obligate

Question 6

Benefits of mixed-species foraging as mutualism

Answer 6

benefits = increased feeding efficiency and better predator defense
ex. zebra and wildebeest are complementary grazers. zebra = superior vision and hearing and wildebeest are often preferred by predators

Question 7

Explain mutualism of mycorrhizal fungus interaction

Answer 7

fungi gets sugars from photosynthesis
plants get root extensions and better access to nutrients

Question 8

Explain/Example of plant-pollinator mutualism

Answer 8

transport of gametes for plant
food for pollinator

Question 9

Example of legumes and rhizobium interaction

Answer 9

plant/legumes = nitrogen
rhizobium = carbon

Question 10

What is the “temptation” in mutualism

Answer 10

cheating (conflicts of interest)

Question 11

Explain yucca moths and yucca plants as an example of cheating in mutualism

Answer 11

yucca moths use maxillary tentacles to pollinate yucca plants
can lack tentacles and lay eggs in plants without pollinating and cheating

Question 12

How can yucca plants prevent the cheating of yucca moths

Answer 12

fruit only develops for food when pollinated and can cut off fruits particularly infested with larvae

Question 13

Explain the example of nectar robbing as an example of cheating in mutualism

Answer 13

usually insects go inside flowers and get pollen on them when eating the flower so they also spread pollen
involves not going inside the flower to feed because it’s easier and therefore don’t penetrate the flower and don’t get any pollen on them

Question 14

What are the 3 ways orchids and other flowering plants can cheat

Answer 14

1. completely nectarless species
2. nectarless individuals in otherwise nectar-producing species
3. nectarless flower within nectar-producing inflorescences

Question 15

Explain cheating in legumes

Answer 15

many legumes produce fruits that have no food value, but mimic fruits that are valuable

Question 16

Explain Mullerian mimicry vs. Batesian mimicry

Answer 16

Mullerian = when everyone is defended (ex. toxic) = mutualism
Batesian = when a species in a mimicry system is undefended (not-toxic) = cheating/parasitism because batesian mimics fail to pay the costs associated with defense

Question 17

How can cheating occur in mycorrhizal fungi

Answer 17

arbuscular mycorrhizal fungi can act as parasites under certain circumstances by taking carbon but failing to provide many nutrients back

Question 18

When would you expect cheating to readily evolve

Answer 18

in general it readily evolves, especially in pairs of mutualists whose interests are highly divergent (different)

Question 19

When would you expect less cheating

Answer 19

when interests are aligned

Question 20

When would cheating not expect to evolve much at all

Answer 20

when cheating substantially limits fitness (ex. yucca moths)