Mutualism Flashcards
What are mutualisms?
- Mutually beneficial interactions
- Either immediate benefit, or increases population
Species interactions
- Defined by effects on either partner
- Can be positive, negative, or neutral
Limitations to this approach
- Very rigid
- Interactions can change in time and space
Instead, species interaction wheel
Interactions can be context-dependent
- Change based on abiotic and biotic factors
Mutualism equation
Biotic and abiotic factors may change costs and benefits
How can a mutualism shift?
How can we categorize mutualism?
- Obligate vs. facultative
- Generalized vs. specialised
Obligate mutualism
- Species cannot survive/reproduce without the mutualist
Facultative mutualism
- Species does better in the presence of mutualism, but can still survive/reproduce without it
Generalized mutualism
- Multiple partner species
Specialized mutualism
- One partner species
Assymetry of speciation
- Mutualistic networks are often asymmetrical
- What costs could come with loyalty?
Cheaters and exploiters
Cheater:
- Individual from a species that could be a legitimate mutualism, but instead removes the reward without paying a cost
Exploiter:
- A species that only removes the reward of a mutualism, without paying the cost
Nectar robbing of Tacoma sp.
- Legitimate pollinator: hummingbirds
Exploiter: Carpenter bee
- Cannot fit in flower to legitimately visit
- Cuts holes at base of flower to extract nectar
- Avoid costs, receive benefits
Cheater: honeybee
- When a hole is present, will nectar rob
- Otherwise, will legitimately visit
Does this affect the plant?
- Probably not
How do mutualisms persist in the face of cheating?
- Sanctions & differential partitioning of resources & spacial dynamics
Differential partioning of resources
- Reduce resources to cheaters
- Whoever freeloads now, might be beneficial later
