Pairs of cleaner fish prolong interaction duration with client reef fish by increasing service quality

We present field experiments showing that levels of cooperation quantitatively predict the duration of interactions between the cleaner wrasse and its reef fish clients. Our study contrasts the general assumption that cooperating is a discrete decision, lacking a time dimension that would allow for continuous rather than discrete decisions. Our results precisely fit the predictions of a recent model that attempted to increase biological validity through the incorporation of a time component in cooperative interaction

Octopuses punch fishes during collaborative interspecific hunting events

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Supplementary Figures & Analyses from Mutualistic cleaner fish maintains high escape performance despite privileged relationship with predators

Supplementary figures & statistical analyse

Supplementary Video 1 from Mutualistic cleaner fish maintains high escape performance despite privileged relationship with predators

Examples of the cleaning behaviour of Labroides dimidiatus in the wild (interactions with predators & punishment). All videos were filmed by Simon Gingins on the Great Barrier Reef, Australia

Data from: Power and temptation cause shifts between exploitation and cooperation in a cleaner wrasse mutualism

In many instances of cooperation, only one individual has both the potential and the incentive to ‘cheat’ and exploit its partner. Under these asymmetric conditions, a simple model predicts that variation in the temptation to cheat and in the potential victim's capacity for partner control leads to shifts between exploitation and cooperation. Here, we show that the threat of early termination of an interaction was sufficient to induce cleaner wrasse Labroides dimidiatus to feed selectively against their preference (which corresponds to cooperatively eating client fish ectoparasites), provided that their preference for alternative food was weak. Under opposite conditions, cleaners fed selectively according to their own preference (which corresponds to cheating by eating client mucus). By contrast, a non-cleaning fish species, Halichoeres melanurus, failed to adjust its foraging behaviour under these same conditions. Thus, cleaners appear to have evolved the power to strategically adjust their levels of cooperation according to the circumstances

The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms

Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter “cleaners”). Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right) in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.publishe

The global structure of marine cleaning mutualistic networks

Aim We studied the underlying biotic and abiotic drivers of network patterns in marine cleaning mutualisms (species feeding upon ectoparasites and injured tissues of others) at large spatial scales. Location Time period Eleven marine biogeographical provinces. 1971-2018. Major taxa studied Methods Reef fish and shrimps. We combined field and literature data to test whether recurrent patterns in mutualistic networks (nestedness, modularity) describe the distributions of marine cleaning interactions. Nested network structures suggest that some cleaner species interact with many clients while the others clean fewer, predictable subsets of these clients; modular network structures suggest that cleaners and clients interact within defined, densely connected subsets of species. We used linear mixed models to evaluate whether the life-history traits of cleaners contribute to the emergence of these patterns locally and whether environmental and geographical factors influence the network structures. Results Main conclusions Marine cleaning networks were more nested than modular. Nestedness was prevalent in communities with dedicated cleaners (ones that feed exclusively by cleaning), whereas communities with only facultative cleaners (ones that clean opportunistically) were generally unstructured. Cleaner type and taxa were the only traits shaping networks, with dedicated fish cleaners contributing disproportionally more than facultative cleaners and shrimps to the emergence of nestedness. Although cleaner species seem concentrated around the tropics and biodiversity centres, we did not detect an influence of environmental and geographical factors on network structures. Dedicated species are key in shaping the structure of marine cleaning mutualistic networks. By relying exclusively on cleaning to feed, dedicated cleaners interact with most of the available clients and form the network core, whereas the opportunistic facultative species tend to clean the most common clients. We hypothesize that trophic niche variation and phenotypic specialization are major drivers of this asymmetry in marine mutualisms. Our study strengthens the links between biotic interactions at the community level and the distribution of species and specializations at larger spatial scales

Data for: The performance of the cleaner wrasse Labroides dimidiatus in a reversal learning task varies across experimental setups

Data, metadata and analysis script for "The performance of the cleaner wrasse Labroides dimidiatus in a reversal learning task varies across experimental setups" by S. Gingins, F. Marcadier, S. Wismer, O. Krattinger, F. Quattrini, R. Bshary & S.A. Binning