Week 6: Double agents
The mutualism-parasitism continuum — the same fungal partner shifting role by host and by context — and the sanctions that keep it from settling one way permanently.
TB0815 · diorama S. Brandt, NHM Basel · CC BY 4.0
Dispatch 06
Dispatch 06- Date
- 29 March 2027
- Metaphor
- Double agents — the same actor mutualist on one front, exploitative on another
- Phenomenon
- Context- and partner-dependent shifts along the mutualism-parasitism continuum in mycorrhizal fungi, and the partner-sanctioning mechanisms that keep this in check
Outline#
- the same fungal species, and sometimes the same individual, can behave as a net mutualist with one plant and a net drain on another, depending on partner identity and environmental context such as light or soil nutrient status
- this ties directly back to week 2’s biological market and weeks 4–5’s cheating and defence: partner-fidelity feedback, the same sanctioning logic behind the labelling experiments, is one mechanism that keeps a partner from sliding permanently into the exploitative role
- “double agent” earns its keep here more than most weeks’ labels: there is a real, measured behavioural switch tied to identifiable conditions, not just an observer’s choice of framing
- the Field Dispatch asks you to find and argue one such case yourself, against the same evidentiary standard used in this lecture
Teaching team
- Dr. Marguerite Osei — convenor