We ’ ve established the fact that Eavesdropping is common...

1. We’ve established the fact that Eavesdropping is common... … this paves the way for modifying other games we’ve already discussed COOPERATION HAWK-DOVE

4. COOPERATION Direct Reciprocity– “I scratch your back you scratch mine” Indirect Reciprocity – one does not expect return from the recipient but from someone else - “Give, and you shall be given” Indirect Reciprocity involves reputation and status; individuals are continually assessed and reassessed

5. Evolution of indirect reciprocity by image scoring – Nowak and Sigmund 1998 • Cooperation includes benefits and costs • If donor cooperates image score increases; if not it decreases • Image score is honest and perfect public information • Pure Discerning cooperation evolves – cooperate with everyone with a image score > 0 • Requires : p >c/b – the probability of knowing the image score (p) of the recipient must exceed c:b ratio • Group size effect: groups of 20 cooperate; whereas rare for groups of 100 (imperfect information)

6. Group size effect: groups of 20 cooperate • whereas rare for groups of 100 (imperfect information)

7. Evolution of indirect reciprocity by image scoring – Nowak and Sigmund 1998 • Cooperation includes benefits and costs • If donor cooperates image score increases; if not it decreases • Image score is honest and perfect public information • Pure Discerning cooperation evolves – cooperate with everyone with a image score > 0 • Requires : p >c/b – the probability of knowing the image score (p) of the recipient must exceed c:b ratio • Group size effect: groups of 20 cooperate; whereas rare for groups of 100 (imperfect information) COOPERATION EVOLVES W/O DIRECT RECIPROCITY NO GOOD ACT SHOULD GO UNDISPLAYED

8. But does image scoring really occur?

9. 2000 interactions/day w/queue • Eat parasites (coop) & mucosal • tissue/scales (defect) • The latter leads to client “jolt” • so an observable cue

10. Jolts are predictors: • 12-18/min among biting cleaners • 2-3/min among coop cleaners • Do clients image score? • If previous client ends w/conflict (jolt/chasing): • 100% bystanders (queue) depart • w/o conflict 100% approach • Audience effects? • 17 vs. 6 cleaners spp showed (-) relationship • between jolts and bystander presence • And also observed in Sergeant major

11. HAWK-DOVE – Johnstone 2001 Eavesdropping as a new strategy to play H-D games • Play Hawk when you observed your opponent losing • Play Dove when you observed opponent winning • Hawk-Dove-Eavesdrop is a mixed strategyESS It does well when rare by anticipating other individual’s behavior; but cannot anticipate other Eavesdroppers and so does not get fixed

12. No pure strategy ESS unless V>C Dove Hawk EDs

13. HAWK-DOVE – Johnstone 2001 Eavesdropping as a new strategy to play H-D games • Play Hawk when you observed your opponent losing • Play Dove when you observed opponent winning • Actually enhances the frequency of fighting – this is because the victory in one round increases the likelihood of winning again This “image” provides an additional benefit to winning favoring aggression How does E’s change the level of fighting? NO VICTORY SHOULD GO UNDISPLAYED

14. Fighting increases w/ E and with V/C Perfect info H-D-E Imperfect info H-D-E H-D

16. Victory displays and acoustics in Tropical boubous

19. SOCIAL EAVESDROPPER INFO Clearly Social Eavesdropping occurs by both sexes INFO