Q8: Endophyte/Animal Symbiosis & Community Ecology

Question 1

Neutral symbioses in which one partner benefits and the other is neither benefitted or harmed.

Answer 1

Commensalism

Question 2

Ways endophytes are disseminated.

Answer 2

(1) Vertically in seed and (2) horizontally by spore.

Question 3

The food source of fungus-cultivating termites.

Answer 3

Modified cellulose

Question 4

Ways that plants benefit from endophytes.

Answer 4

(1) Herbivore resistance, (2) protection from pathogens, (3) drought tolerance, (4) growth enhancement, (5) heavy metal tolerance, and (6) thermotolerance.

Question 5

Endophytes of woody plants are dispersed only by (vertical/horizontal) dissemination.

Answer 5

Horizontal

Question 6

(T/F) The symbiosis between termites and fungus has evolved many times.

Answer 6

False.

Question 7

Gongylidia

Answer 7

Swollen hyphal tips that form as a result of mycelial pruning by ants. The main source of food for leafcutter ants.

Question 8

(T/F) Leafcutter ants are often highly specialized with only one cultivated strain of a specific fungal species.

Answer 8

True; some species are more generalist, and can reform relationships with free-living fungi.

Question 9

In what stage of the symbiosis between Leucoagaricus spp. and leafcutter ants does the fungus usually fruit?

Answer 9

After the ants abandon the nest.

Question 10

C-selective fungi.

Answer 10

Combative fungi, characterized by slow growth rate; good competitors.

Question 11

What do chytrid endosymbionts provide for ruminants?

Answer 11

The mycelium can break down larger material to make it more available for other microbes.

Question 12

S-selected fungi.

Answer 12

Stress tolerant fungi adapted to specific extreme environments.

Question 13

Fungal community succession generally proceeds from communities dominated by (R/C/S)-selected species to (R/C/S)-selected species.

Answer 13

R-selected to C-selected

Question 14

Fungal community succession generally proceeds from communities (with/without) dominant species to communities (with/without) dominant species.

Answer 14

Without dominant species to with dominant species.

Question 15

The major drawback of direct observation of a fungal community.

Answer 15

Non-fruiting fungi can be missed or unidentifiable.

Question 16

Antibiosis in which secondary compounds are used to kill competing hyphae.

Answer 16

Fungicidal antibiosis

Question 17

Examples of direct effects of animals on fungal communities.

Answer 17

Fungivory, grazing.

Question 18

(T/F) Fungal commensals can be free-living.

Answer 18

True, requiring a host for only a stage in life cycle. Others, however, are never free-living.

Question 19

R-selecting fungi.

Answer 19

Ruderal/pioneer species selected for short lifespans and high rate of production in disturbed environments.

Question 20

Ruderal/pioneer species selected for short lifespans and high rate of production in disturbed environments.

Answer 20

R-selecting fungi.

Question 21

The fungus that is cultivated by termites.

Answer 21

Termitomyces

Question 22

Fungal community succession generally proceeds from communities dominated by (many/fewer) species to (many/fewer) species.

Answer 22

Many species to fewer species.

Question 23

Most endophytes belong to which group?

Answer 23

Ascomycota

Question 24

Direct antagonism.

Answer 24

A contact phenomenon that leads to the destructions of hyphae. Aggressive behavior by one or both fungi that requires hyphal contact.

Question 25

Endophytes

Answer 25

Fungi that live within plants but cause no outward symptoms.

Question 26

The negative influence of one fungus on another via production of secondary compounds, such as antibiotics.

Answer 26

Antibiosis.

Question 27

Endophytic dissemination in which spores are produced on dead/dying plant tissue, going on to infect and colonize tissues of a new plant.

Answer 27

Horizonal dissemination

Question 28

The FOUR broad influences on the composition and diversity of fungal communities.

Answer 28

(1) Substrate/nutrient availability, (2) physical environmental factors, (3) interspecific interactions, (4) impacts of animals.

Question 29

The range of leafcutter ants.

Answer 29

South America to southern United States.

Question 30

How do endophytes protect plants from pathogens?

Answer 30

(1) Production of toxins, (2) competitive exclusion, or (3) stimulating host defense.

Question 31

Combative fungi, characterized by slow growth rate; good competitors.

Answer 31

C-selective fungi

Question 32

What do leafcutter ants get out of the symbiosis with fungi?

Answer 32

The ability to use cellulose as a food source.

Question 33

Endosymbionts

Answer 33

Symbionts that live most of their life cycle within another organism.

Question 34

A contact phenomenon that leads to the destructions of hyphae. Aggressive behavior by one or both fungi that requires hyphal contact.

Answer 34

Direct antagonism.

Question 35

Aggressive behavior by one or both competitor that does not require hyphal contact.

Answer 35

Indirect antagonism.

Question 36

Ruderal

Answer 36

The term for pioneer/R-selected species.

Question 37

Agricultural activities practices by leafcutter ants.

Answer 37

(1) Cultivation, (2) fertilization, (3) weed/pest control, (4) pruning, (5) specialized labor forces, (6) domestication of new crops/crop improvement.

Question 38

(T/F) The symbiosis between leafcutter ants and Leucoagaricus spp. has evolved multiple times.

Answer 38

False

Question 39

Fungicidal antibiosis.

Answer 39

Antibiosis in which secondary compounds are used to kill competing hyphae.

Question 40

(R/C)-selective fungi tend to use more complex substrates.

Answer 40

C-selective

Question 41

Mycorrhizal fungal communities tend to become (more/less) host-specific as a forest matures.

Answer 41

More

Question 42

Commensalism

Answer 42

Neutral symbioses in which one partner benefits and the other is neither benefitted or harmed.

Question 43

Swollen hyphal tips that form as a result of mycelial pruning by ants. The main source of food for leafcutter ants.

Answer 43

Gongylidia

Question 44

Fungi that live within plants but cause no outward symptoms.

Answer 44

Endophytes

Question 45

Antibiosis.

Answer 45

The negative influence of one fungus on another via production of secondary compounds, such as antibiotics.

Question 46

What do ambrosia beetles and Ambrosiella get out of their symbiosis?

Answer 46

The beetles get food (the fungus) and the fungus receives transmission and refuge from competitors.

Question 47

The genus of fungus that is primarily cultivated by leafcutter ants.

Answer 47

Leucoagaricus

Question 48

The term for pioneer species.

Answer 48

Ruderal

Question 49

The key difference between endophytes and mycorrhizae.

Answer 49

Endophytic fungi live entirely within plant tissue with no external connections.

Question 50

Horizontal dissemination.

Answer 50

Endophytic dissemination in which spores are produced on dead/dying plant tissue, going on to infect and colonize tissues of a new plant.

Question 51

The specialized structure on the thorax of female ambrosia beetles for carrying fungi.

Answer 51

Mycangium

Question 52

Approaches to characterize and quantify fungal communities.

Answer 52

(1) Direct observation, (2) isolation, (3) molecular methods.

Question 53

Indirect antagonism.

Answer 53

Aggressive behavior by one or both competitor that does not require hyphal contact.

Question 54

The genus of snail that has been found to cultivate fungi.

Answer 54

Littoria

Question 55

Mycangium

Answer 55

The specialized structure on the thorax of female ambrosia beetles for carrying fungi.

Question 56

Vertical dissemination.

Answer 56

Endophytic dissemination in which the infection is passed from parent to progeny via seed.

Question 57

How do endophytes provide herbivore resistance to plants?

Answer 57

Production of toxins that reduce herbivory.

Question 58

(Vertical/horizonal) dissemination is found primarily in the endophyte-grass symbiosis.

Answer 58

Vertical.

Question 59

Fungistatic antibiosis.

Answer 59

Antibiosis in which secondary compounds are used to slow the growth of other fungi.

Question 60

Examples of indirect effects of animals on fungal communities.

Answer 60

Inputs of dung/urine, changing composition of plant communities.

Question 61

The term for pioneer/R-selected species.

Answer 61

Ruderal.

Question 62

The fungus cultivated by ambrosia beetles.

Answer 62

Ascomycota -> hyphomycetes -> Ambrosiella

Question 63

Endophytic dissemination in which the infection is passed from parent to progeny via seed.

Answer 63

Vertical dissemination.

Question 64

Major drawbacks to using isolation to study fungal communities.

Answer 64

Many fungi do not grow well in culture, have very specific requirements for growth in culture, or are not good competitors on artificial media.

Question 65

(T/F) Endophytes are parasitic.

Answer 65

False, most are mutualistic.

Question 66

R-selecting fungi are primarily (sexual/asexual).

Answer 66

Asexual

Question 67

What do the fungi get out of the symbiosis with leafcutter ants?

Answer 67

A readily available food supply.

Question 68

Broad possible outcomes of interspecific interactions within a fungal community.

Answer 68

(1) Stimulation of one or both species, (2) mutual tolerance, or (3) intolerance/antagonism.

Question 69

Most endosymbionts tend to be (mutualistic, commensal, parasitic).

Answer 69

Commensal.

Question 70

The alternate name for leafcutter ants.

Answer 70

Attine ants

Question 71

What is the endophyte Neotyphodium known for?

Answer 71

Reducing grass herbivory by producing alkaloids

Question 72

What is a common example of a commensal endosymbiont that can become a parasite under certain conditions?

Answer 72

Candida albicans

Question 73

How does the Littoria snail cultivate fungus?

Answer 73

It creates wounds that weak parasitic fungi can exploit, then it eats the fungi.

Question 74

What type of insect is Dutch Elm Disease spread by?

Answer 74

Bark beetles

Question 75

What is the Mycangium of an Ambrosia beetle used for?

Answer 75

Carrying fungi!

Question 76

What is the nutrient aquisition strategy for most C-selected / combative fungi?

Answer 76

Wood decay

Question 77

What is the character trait of Xerophilic fungi?

Answer 77

Drought loving

Question 78

T or F. Mycoparasitism includes both necrotrophs and biotrophs.

Answer 78

True.

Question 79

What compound does Trichoderma, and other mycoparasites, use to break down host fungal cell walls?

Answer 79

Chitinases

Question 80

Why are R-selected pioneers not good competitors?

Answer 80

They can't handle antibiotics.