Rhedouan Bshary Université de Neuchâtel, CH Title A unifying concept for stable cooperation: lessons from the cleaner fish mutualism. Abstract Humans are highly social animals and often help unrelated individuals that may never reciprocate the altruist’s favour. This apparent evolutionary puzzle may be explained by the altruist’s gain in social image: image-scoring bystanders, also known as eavesdroppers, notice the altruistic act and therefore are more likely to help the altruist in the future. Such complex indirect reciprocity based on altruistic acts may evolve only after simple indirect reciprocity has been established, which requires two steps. First, image scoring evolves when bystanders gain personal benefits from information gathered, for example, by finding cooperative partners. Second, altruistic behaviour in the presence of such bystanders may evolve if altruists benefit from access to the bystanders. Here, we provide experimental evidence for both of the requirements in a cleaning mutualism involving the cleaner fish Labroides dimidiatus. These cleaners may cooperate and remove ectoparasites from clients or they may cheat by feeding on client mucus. As mucus may be preferred over typical client ectoparasites, clients must make cleaners feed against their preference to obtain a cooperative service. We found that eavesdropping clients spent more time next to ‘cooperative’ than ‘unknown cooperative level’ cleaners, which shows that clients engage in image-scoring behaviour. Furthermore, trained cleaners learned to feed more cooperatively when in an ‘imagescoring’ than in a ‘non-image-scoring’ situation. CV since 10/2004 Professor in behavioural ecology at the University of Neuchâtel 07/2003-07/2004 Lecturer in behavioural ecology at the School of Biological Sciences at Liverpool University 09/2002-06/2003 Research project collaboration between the MPIV Seewiesen and the Cambridge Zoology Department on game theoretic modelling, cleaning symbiosis and on interspecific cooperative hunting between groupers and morray eels (DFG grant) 08/2002 Nico Tinbergen award from the Ethological Society (equivalent to the ASAB young scientist award) 09/2000-08/2002 Marie Curie grant from the European Union to work with Dr. Rufus Johnstone at Cambridge, UK, continuing the work on cleaning symbiosis 09/1997-08/2000 Start of own project financed by the German Science Foundation (DFG grant) on marine cleaning symbiosis at Ras Mohammed National Park, Egypt and on Lizard Island, Australia 10/1995-08/1997 Post-doc at the MPIV Seewiesen. Further studies on arboreal monkeys in the Taï National Park, Ivory Coast. The two main topics were: learning in predator-prey arms races and communication between prey and predator 01/1992-10/1995 PhD at the MPIV Seewiesen on the advantages of mixed species associations in arboreal monkeys in Taï National Park, Ivory Coast Supervisor: Dr. Wolfgang Wickler and Prof Dr. Gerhard Neuweiler 07/1991 Master thesis at the Max-Planck-Institute for Behaviour and Physiology, Seewiesen on the mechanisms of social appeasement in domestic fowl. Supervisor: Prof Dr. Jürg Lamprecht Selected recent publications Bshary R & Grutter AS (2006) Image scoring and cooperation in a cleaning mutualism. Nature 441 (7096), 975-978 pf Bshary R, Hohner A, Ait-El-Djoudi K, Fricke H (2006) Interspecific Communicative and Coordinated Hunting between Groupers and Giant Moray Eels in the Red Sea. PLoS Biology. pdf Bshary R (in press) Machiavellian intelligence in fishes. In"Learning and Cognition in Fishes". (Eds. Culum Brown, Kevin Laland and Jens Krause), Blackwell Bshary R (in press) Interactions between red colobus monkeys and chimpanzees. In: Monkeys of the Taï Forest: an African primate community. (Noë R, McGraw WS & Zuberbühler K, eds). Cambridge: Cambridge University Press Bshary R (in press) Reciprocal altruism. In: The Encyclopedia of Applied Animal Behaviour and Welfare. CABI Publishing. Bshary R (in press) Game theory In: The Encyclopedia of Applied Animal Behaviour and Welfare. CABI Publishing Bshary R (in press) Interspecific interactions. In: The Encyclopedia of Applied Animal Behaviour and Welfare. CABI Publishing Bshary R, Salwiczek L & Wickler W (in press) Social cognition in non primates. In: "evolutionary psychology" (Eds. Louise Barrett & Robin Dunbar), Oxford University Press. Bshary R (in press) Interactions between red colobus monkeys and Chimpanzees. In: Monkeys of the Taï Forest: an African primate community. (Noë R, McGraw WS & Zuberbühler K, eds). Cambridge: Cambridge University Press Institution address Prof. Redouan Bshary Université de Neuchâtel, Faculté des Sciences, Département d'éthologie Emile Argand 13, Case postale 2 CH-2007 Neuchâtel 7 Phone: 032 718 3005/3000 Fax: 032 718 3001 redouan.bshary@unine.ch