Societies, mutualists, & parasites - part 2 Flashcards
Why does mutualism break down?
it shifts from a +/+ interaction to a +/- interaction
how can a mutualism breakdown be explain as?
it can be explained by “why pay for something if you can get it for free?
define Evolutionary cheating
Evolution of traits that allow an organism to receive the benefits of a beneficial interaction without reciprocating
why are cheater traits favored by selection
same or greater benefits can be received without the cost of providing a service to a partner
what do cheater traits result in
- a net gain in resources and offspring production
- as long as they can get away with it
mutualism breakdown example
Acacia-ant mutualism with 4 ant species
mutualism breakdown - acacia-ant mutualism
- One species provides weak to no defense to the tree.
- but it still uses nesting and food resources provided by the tree
mutualism breakdown: acacia-ant mutualism - what has the weak ant evolved to do?
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.
mutualism breakdown: acacia-ant mutualism - how does it parasitize the tree
- 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
parasites and societies - diversity of interactions
- Endoparasitic individual parasites.
- Ectoparasitic individual parasites.
- Social parasites — one society parasitizes the social mechanisms of another whole society.
define parasitism
an ecological interaction where we often see an extreme evolutionary arms race between host and parasite.
define evolutionary arms race
evolutionary escalation of adaptation and counter-adaptation between host and parasite (and any consumer resource pairing of species).
evolutionary arms race in parasitism - what does selection favor in the host
it favors traits in the host that maximize escape from the interactions with the parasite
evolutionary arms race in parasitism - what does selection favor in the parasite
it favors traits in the parasitic species that prevent the host from escaping the interaction with the parasite
General classes of adaptations in parasites that alter their ecological interactions with a social host
- Invisibility
- Mimicry.
- Attractiveness.
- Tolerance of host defenses.
- Neutralization of host defenses.