Guest Speaker Lecture

Question 1

Natural Selection

Answer 1

survival of the fittest

occurs at level of reproduction

Question 2

symbiotic relationships feature multiple _________

Answer 2

reproductives

maxing reproduction is in the best interest of each organism

Question 3

pathogenesis

Question 4

mutualism

Question 5

commensalism

Question 6

all macroorganisms live with _______

Question 7

How do these microbes interact with their host and each other?

Question 8

How do these interactions change?

Question 9

How does coevolution function given such complexity?

Question 10

Attine Ants

Question 11

Attine diversity

Answer 11

Gradient of evolutionary sophistication
- colony size
- nutrient source
-caste differentiation

Question 12

Trachymyrmex septentrionalis

Answer 12

Klassen lab model system
Ranges in USA from NJ to TX
Small colonies ~ 1000 workers
Eat mostly oak catkins, catepillars frass, fresh leaves

Question 13

Trachymyrmex septentrionalis body characteristics

Answer 13

redish brown
have wings to do a mass swarm for mating, then the males die, the women start a new colony

Question 14

Trachymyrmex septentrionalis

Answer 14

Live in NJ pine barrens, also done work on south east coast

Question 15

What do we look for in ID colony?

Answer 15

small mound 5-6 inches
dig a hole next to it until there is a wiggle,
then you can find the fungus garden underground which is the symbio the ants are growing underground with the plant material they harvest

Question 16

What type of forest are they found?

Answer 16

Oak pine mix, preferably an area which has been burned

Question 17

How do you take samples of ants?

Answer 17

Asperator, a glass rod which goes in a tube, attached to another tube attached to the mouth, to suck up the ants into the tube to the vile

Question 18

Once captured, how are they stored/kept?

Answer 18

In a sand boxed chamber with a fungus garden, water, and airways

Question 19

Leaf-cutter ants

Answer 19

The most highly evolved fungus-growing ant
Atta:
- millions of colony members
- dominant herbivore in neo-tropical forests

Question 20

Life cycle of a leaf-cutter colony

Answer 20

production of sexuals -> fungus fragment -> mating flight -> colony founding -> colony growth -> production of sexuals

Question 21

Clonal propogation

Answer 21

the queen carries the fungus to start the new garden

Question 22

When the queen dies….?

Answer 22

The colony dies

Question 23

Why is clonal propogation advantageous?

Answer 23

Allows co-specialization
- fungal gongylidia of the leaf-cutter cultivar
-behavioral adaptation
Fungus garden propagation by the queen
Ant nest structure to house the fungus
garden and dump
Disease management

Question 24

How does the fungus contribute to clonality?

Answer 24

fungus-fungus antagonism increases with increasing genetic distance

fungus enzymes pass through the ant’s digestive tract and are absorbed by the grden to help leaf digestion

Question 25

Mutualism of plant and fungal garden problem

Answer 25

Pathogen susceptibility

Question 26

Pathogen susceptibility

Answer 26

If the pathogen gets into a healthy garden then the ant can also get sick or vice versa

Question 27

Escovopsis

Answer 27

Shows specificity to different cultivar strains

Some prduce Shearinines that inhibit ant movement and cause ant death

Question 28

Ant solution #1: Antiseptic Behavior

Answer 28

1. Waste, old, and diseased biomass transferred from gardens to dumps
   - maintained by specific castes to avoid garden contamination

Increased fungus grooming upon infection}

filter and collect spores of the contaminant to clean themselves

If you have hitchhikes, there are more spores than those not exposed to hitchhikers

Question 29

Metarhizium

Answer 29

ant pathogen

Question 30

Ant solution #2: chemical defense

Answer 30

Metapleural gland antimicrobial secretions

Question 31

Ant solution #3: Switch cultivars

Answer 31

Benefit: access more diversity from the wider population

Disadvantage: limit the specialization of a tighter symbiosis

Question 32

Fungus solution

Answer 32

Form fruiting bodies

-genetic interactions with the larger free-living population
-dispersal from site of pathogen infection

Question 33

Ant solution #4 Find new friends

Answer 33

Pseudonocardia: antibiotic-producing actinobacteria

Question 34

Pseudonocardia

Question 35

Genome-guided natural product discovery

Answer 35

analyzing natural product biosynthetic gene help us discover new compounds

Question 36

Pseudonocardia Natural Product Capacity

Question 37

Problem with a 3rd symbiont #1

Answer 37

Potential antagonism with th cultivar fungus

Question 38

Problem with a 3rd symbiont #2

Answer 38

Pseudonocardia compete with each other
- presumably living in ant glands is advantageous fro Pseudonocardia
- competition between pseudonocardia may select against Escovopsis defense

Question 39

Bacteria in T. septentrionalis fungus gardens have very high ______

Answer 39

high diversity

Question 40

Northern forests vary seasonally

Answer 40

T. septentrionalis ants are inactive in winter
- Enter torpor

Varies by geography/climate

Food availability also varies by season

Question 41

Seaonsal variability of T. septentrionalis fungus garden microbes

Answer 41

T. septentrionalis fungus gardens collected in July are distinct

Represents peak of ant foraging activity

Transient microbes or colonists

Question 42

What metabolites are produced in fungus gardens?

Question 43

Wild fungus gardens are chemically diverse

Question 44

Pepaibol secondary metabolites occur in wild fungus gardens

Question 45

Tricoderma - A Fungus Garden Parasite

Question 46

Ants prevent Trichoderma infections by “trashing”

Question 47

Crude Trichoderma Extracts Induce Ant Trashing

Question 48

Peptaibols induce ant trashing

Question 49

Conclusion