Week 9: Arms races

The evolutionary logic connecting cheating (weeks 4 and 6) to sanctioning (weeks 2 and 6), and what "arms race" costs you when you say it out loud.

TB0815 · diorama S. Brandt, NHM Basel · CC BY 4.0

Dispatch 09

Date: 19 April 2027
Metaphor: Arms races — escalating measures and countermeasures between opposed interests
Phenomenon: Coevolution between exploitative strategies and the partner-choice and sanctioning mechanisms that oppose them

Outline

if cheating symbionts (week 4) and context-dependent exploitation (week 6) impose a real cost, selection should favour hosts and fungi able to detect and punish it — this is the evolutionary logic behind the sanctioning mechanisms introduced in weeks 2 and 6
orchid-fungus specificity is one place this plays out: how narrowly or broadly a fungal partner associates with orchid lineages tracks, in part, the cost of being exploited by a given lineage
what “arms race” buys: a reason to expect detection and punishment mechanisms exist at all, without needing intent on either side
what it costs: an arms race is usually inferred from present-day defences, not observed as a sequence of escalating moves over time. Say that plainly rather than implying a single semester’s reading watched an escalation happen