Behavioral Ecology Advance Access published online on June 25, 2008
Behavioral Ecology, doi:10.1093/beheco/arn067
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Cleaner fish cause predators to reduce aggression toward bystanders at cleaning stations
a School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia b Department of Zoology, Université de Neuchâtel, Rue Emile-Argand 11 Case postale 158, CH-2009 Neuchâtel, Switzerland
Address correspondence to K.L. Cheney. E-mail: k.cheney{at}uq.edu.au.
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Abstract |
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Mutualisms, in which both participants gain a net benefit, are ubiquitous in all ecosystems, and the importance of understanding their broader ecological context has been demonstrated many times. Indirect effects of mutualisms may have important implications for surrounding ecosystems through changes in density, species composition, or behavior; however, the latter has been difficult to quantify. In fish cleaning mutualisms, cleaners benefit by removing and consuming ectoparasites from clients, whereas clients benefit from a reduction in parasite load. Cleaner fish are also thought to benefit from immunity to predation and use tactile stimulation as a preconflict management strategy to manipulate partners' decisions and to avoid being eaten by piscivorous client fish. Here we show, using a laboratory experiment, that the presence of cleaner fish resulted in nearby fish not involved in the cleaner–client mutualism experiencing less aggression (chases) from predatory clients. In addition, the rate that piscivorous clients chased prey was negatively correlated with the amount of tactile stimulation given to the predator by the cleaner. These data suggest that, in the laboratory, the risk of aggression from predators toward nearby prey fish was greatly reduced as a by-product of cleaner fish presence and tactile stimulation of predators by cleaner fish. These results raise the question of whether cleaning stations act as safe havens from predator aggression.
Key words: cleaning symbioses, coral reef fish, indirect effects, mutualisms, tactile stimulation.
Received 10 September 2007; revised 15 May 2008; accepted 17 May 2008.