Societies, mutualists, & parasites - part 2

Question 1

Why does mutualism break down?

Answer 1

it shifts from a +/+ interaction to a +/- interaction

Question 2

how can a mutualism breakdown be explain as?

Answer 2

it can be explained by “why pay for something if you can get it for free?

Question 3

define Evolutionary cheating

Answer 3

Evolution of traits that allow an organism to receive the benefits of a beneficial interaction without reciprocating

Question 4

why are cheater traits favored by selection

Answer 4

same or greater benefits can be received without the cost of providing a service to a partner

Question 5

what do cheater traits result in

Answer 5

• a net gain in resources and offspring production
• as long as they can get away with it

Question 6

mutualism breakdown example

Answer 6

Acacia-ant mutualism with 4 ant species

Question 7

mutualism breakdown - acacia-ant mutualism

Answer 7

• One species provides weak to no defense to the tree.
• but it still uses nesting and food resources provided by the tree

Question 8

mutualism breakdown: acacia-ant mutualism - what has the weak ant evolved to do?

Answer 8

Evolved to colonize trees early and modify the tree to prevent a hostile takeover by a colony of one of the other three ant species — cuts connecting vegetation.

Question 9

mutualism breakdown: acacia-ant mutualism - how does it parasitize the tree

Answer 9

• removes extra-floral nectaries to make the plant less attractive (parasite is more predatory)
• makes entrance holes into the swollen thorns that are too small for the other ant species

Question 10

parasites and societies - diversity of interactions

Answer 10

• Endoparasitic individual parasites.
• Ectoparasitic individual parasites.
• Social parasites — one society parasitizes the social mechanisms of another whole society.

Question 11

define parasitism

Answer 11

an ecological interaction where we often see an extreme evolutionary arms race between host and parasite.

Question 12

define evolutionary arms race

Answer 12

evolutionary escalation of adaptation and counter-adaptation between host and parasite (and any consumer resource pairing of species).

Question 13

evolutionary arms race in parasitism - what does selection favor in the host

Answer 13

it favors traits in the host that maximize escape from the interactions with the parasite

Question 14

evolutionary arms race in parasitism - what does selection favor in the parasite

Answer 14

it favors traits in the parasitic species that prevent the host from escaping the interaction with the parasite

Question 15

General classes of adaptations in parasites that alter their ecological interactions with a social host

Answer 15

• Invisibility
• Mimicry.
• Attractiveness.
• Tolerance of host defenses.
• Neutralization of host defenses.

Question 16

what are forms of infiltration

Answer 16

Invisibility, mimicry, and attractiveness.

Question 17

what do invisibility, mimicry, and attractiveness rely on

Answer 17

• they all rely on ways to exploit or circumvent a society’s recognition system
• involving one or more modes of communication.

Question 18

define aggressive mimicry

Answer 18

mimic copies a harmless model for the purposes of preying upon or parasitizing the dupe

Question 19

example of aggressive mimicry

Answer 19

beetles and army ants

Question 20

aggressive mimicry - beetle

Answer 20

• beetle is small and slow, and army ants move frequently
• it stays with the colony by hitching a ride

Question 21

beetle example - how is the aggressive mimicry facilitated

Answer 21

invisibility and mimicry (chemical and physical)

Question 22

explain a parasites tolerance of host defenses

Answer 22

Parasite’s growth to maturity is not prevented by host defenses (either social or immune defenses).

Question 23

example of parasite tolerance

Answer 23

Phorid flies (decapitating flies)

Question 24

What is lost in parasitic interactions involving societies?

Answer 24

• Parts of individuals within a society.
• Whole individuals within a society
• Food and/or shelter resources.

Question 25

what within a society are often functionally parasites of the whole society.

Answer 25

Predators or parasitoids of an individual

Question 26

Predators or parasitoids of an individual within a society are analogous to what

Answer 26

a parasite consuming cells of a multicellular nonsocial animal.

Question 27

define endoparasites

Answer 27

damage or kill individuals within a society.

Question 28

define ectoparasites

Answer 28

• may damage or kill individuals within a society
• can also steal resources that do not harm living individuals directly

Question 29

define kleptoparasitism

Answer 29

Stealing resources held by another organism.

Question 30

example of kleptoparasitism

Answer 30

hyenas act as social kleptoparasites of lion prides

Question 31

kleptoparasitism via mimicry and eavesdropping in ants - visual mimicry

Answer 31

purpose of resource theft (form of
aggressive mimicry)

Question 32

kleptoparasitism via mimicry and eavesdropping in ants - Pheromone-based “interceptive eavesdropping”

Answer 32

for exploit pheromone information meant for nestmates of the host.

Question 33

kleptoparasitism via mimicry and eavesdropping example

Answer 33

ants use three elements combined to allow kleptoparasitism of guarded food resources

Question 34

kleptoparasitism via mimicry and eavesdropping in ants - three elements used

Answer 34

1. Visual mimicry of the host
2. Pheromone-based “interceptive eavesdropping”
3. Obligate “xenobiotic” nesting ecology