The Selfish Gene: 40th Anniversary edition (Oxford Landmark Science) — Aggression: stability and the selfish machine

1. 1. An evolutionarily stable strategy (ESS) is a strategy that does well against copies of itself.
2. 2. The original claim that retaliator is an ESS in the hawk-dove game was wrong; dove can drift into the population because it behaves indistinguishably from retaliator.
3. 3. Field measurements of costs and benefits in nature have been plugged into ESS models, exemplified by great golden digger wasps in North America.
4. 4. In New Hampshire digger wasps, a true mixed ESS exists where each wasp has a probability of digging or entering a nest, balancing the costs of double-occupation.
5. 5. In speckled wood butterflies, the 'resident always wins' rule is an ESS: the first male to occupy a sun patch is treated as owner and the intruder always concedes.
6. 6. A paradoxical ESS in domestic pigs: the subordinate pig sits by the food trough while the dominant pig works the lever, reversing expected roles.
7. 7. Male crickets show a pseudo-dominance hierarchy; a male is more likely to court females after winning a fight, termed the 'Duke of Marlborough Effect'.
8. 8. The ESS concept is one of the most important advances in evolutionary theory since Darwin, though the author now considers that statement over the top.
9. 9. Progressive evolution may consist of discrete steps from stable plateau to stable plateau, similar to the theory of punctuated equilibrium.