The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Alexandra S. Grutter - One of the best experts on this subject based on the ideXlab platform.
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Optimising cleaning behaviour: minimising the costs and maximising ectoparasite removal
Marine Ecology Progress Series, 2020Co-Authors: Alexandra S. Grutter, Hamish Mccallum, Robert J. G. LesterAbstract:Little is known of how client fish minimise the costs of cleaning behaviour while maximising ectoparasite removal by cleaner fish. Previous studies have found that abundance on fish and infestation behaviour of gnathiid isopods, the main parasite eaten by cleaner fish, varies diurnally. We examined whether reduced foraging is a cost of cleaning behaviour in clients and whether the behaviour of the client fish, the thick-lipped wrasse Hemigymnus melapterus, towards the cleaner fish Labroides dimidiatus varied diurnally to maximise ectoparasite removal, possibly in response to the diurnal changes in the abundance and infestation patterns of gnathiids. We found that during the midday and afternoon, client foraging rates were negatively related to the duration and frequency of inspections, suggesting that cleaning may, at some times of the day, be energetically costly to the client in terms of reduced foraging opportunities. Surprisingly, we found that the duration and frequency of inspections of clients by cleaners did not vary among diel time periods. A model of gnathiid dynamics on individual fish is proposed. It shows that the observed diurnal pattern in gnathiid abundance on fish can be generated with the constant duration and frequency of inspections that was observed in this study. Thus clients would not have more gnathiids removed by modifying their cleaning behaviour.
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Cleaner fish prefer client mucus: support for partner control mechanisms in cleaning interactions
2020Co-Authors: Alexandra S. Grutter, R. BsharyAbstract:Recent studies on cleaning behaviour suggest that there are conflicts between cleaners and their clients over what cleaners eat. The diet of cleaners usually contains ectoparasites and some client tissue. It is unclear, however, whether cleaners prefer client tissue over ectoparasites or whether they include client tissue in their diet only when searching for parasites alone is not profitable. To distinguish between these two hypotheses, we trained cleaner fish Labroides dimidiatus to feed from plates and offered them client mucus from the parrotfish Chlorurus sordidus, parasitic monogenean flatworms, parasitic gnathiid isopods and boiled flour glue as a control. We found that cleaners ate more mucus and monogeneans than gnathiids, with gnathiids eaten slightly more often than the control substance. Because gnathiids are the most abundant ectoparasites, our results suggest a potential for conflict between cleaners and clients over what the cleaner should eat, and support studies emphasizing the importance of partner control in keeping cleaning interactions mutualistic.
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Cleaner wrasse indirectly affect the cognitive performance of a damselfish through ectoparasite removal
Proceedings of the Royal Society B: Biological Sciences, 2018Co-Authors: Sandra A Binning, Simona Colosio, Derek Sun, Joanna Miest, Alexandra S. Grutter, Dominique G Roche, R. BsharyAbstract:Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, Labroides dimidiatus, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish ( Pomacentrus amboinensis) collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.
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Equivalent cleaning in a juvenile facultative and obligate cleaning wrasse: an insight into the evolution of cleaning in labrids?
Coral Reefs, 2016Co-Authors: Alexandra S. Grutter, William E. FeeneyAbstract:Species that exhibit ontogenetic variation in interspecific cleaning behaviours may offer insights into how interspecific cooperation evolves. We investigated the foraging ecology of the yellowtail tubelip wrasse (Diproctacanthus xanthurus), a facultative cleaner as a juvenile and corallivore as an adult, and compared its juvenile ecology with that of juvenile blue-streak cleaner wrasse (Labroides dimidiatus), a closely related and sympatric obligate cleaner. While juveniles of the two species differed in the amount of time they inspected clients, the number of client individuals and species that were cleaned and the proportion that posed did not differ, nor did the number of ectoparasitic isopods in their guts. In contrast, adult yellowtail tubelip wrasse had fewer isopods and more coral mucus in their guts than juveniles. These data support a hypothesized series of events in which juvenile cleaning acts as an evolutionary precursor to obligate cleaning and suggest that the yellowtail tubelip wrasse may present an intermediate between corallivory and cleaning.
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generalized rule application in bluestreak cleaner wrasse Labroides dimidiatus using predator species as social tools to reduce punishment
Animal Cognition, 2016Co-Authors: Sharon Wismer, Alexandra S. Grutter, R. BsharyAbstract:Generalized rule application promotes flexible behavior by allowing individuals to adjust quickly to environmental changes through generalization of previous learning. Here, we show that bluestreak ‘cleaner’ wrasse (Labroides dimidiatus) uses generalized rule application in their use of predators as social tools against punishing reef fish clients. Punishment occurs as cleaners do not only remove ectoparasites from clients, but prefer to feed on client mucus (constituting cheating). We tested for generalized rule application in a series of experiments, starting by training cleaners to approach one of two fish models in order to evade punishment (by chasing) from a ‘cheated’ client model. Cleaners learned this task only if the safe haven was a predator model. During consecutive exposure to pairs of novel species, including exotic models, cleaners demonstrated generalization of the ‘predators-are-safe-havens’ rule by rapidly satisfying learning criteria. However, cleaners were not able to generalize to a ‘one-of-two-stimuli-presents-a-safe-haven’ rule, as they failed to solve the task when confronted with either two harmless fish models or two predator models. Our results emphasize the importance of ecologically relevant experiments to uncover complex cognitive processes in non-human animals, like generalized rule learning in the context of social tool use in a fish.
R. Bshary - One of the best experts on this subject based on the ideXlab platform.
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Cleaner fish prefer client mucus: support for partner control mechanisms in cleaning interactions
2020Co-Authors: Alexandra S. Grutter, R. BsharyAbstract:Recent studies on cleaning behaviour suggest that there are conflicts between cleaners and their clients over what cleaners eat. The diet of cleaners usually contains ectoparasites and some client tissue. It is unclear, however, whether cleaners prefer client tissue over ectoparasites or whether they include client tissue in their diet only when searching for parasites alone is not profitable. To distinguish between these two hypotheses, we trained cleaner fish Labroides dimidiatus to feed from plates and offered them client mucus from the parrotfish Chlorurus sordidus, parasitic monogenean flatworms, parasitic gnathiid isopods and boiled flour glue as a control. We found that cleaners ate more mucus and monogeneans than gnathiids, with gnathiids eaten slightly more often than the control substance. Because gnathiids are the most abundant ectoparasites, our results suggest a potential for conflict between cleaners and clients over what the cleaner should eat, and support studies emphasizing the importance of partner control in keeping cleaning interactions mutualistic.
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population densities predict forebrain size variation in the cleaner fish Labroides dimidiatus
Proceedings of The Royal Society B: Biological Sciences, 2019Co-Authors: Zegni Triki, Elena Levorato, William Mcneely, Justin Marshall, R. BsharyAbstract:The ‘social brain hypothesis' proposes a causal link between social complexity and either brain size or the size of key brain parts known to be involved in cognitive processing and decision-making....
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the performance of cleaner wrasse Labroides dimidiatus in a reversal learning task varies across experimental paradigms
PeerJ, 2018Co-Authors: Simon Gingins, Sharon Wismer, R. Bshary, Fanny Marcadier, Oceane Krattinger, Fausto Quattrini, Sandra A BinningAbstract: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.
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Cleaner wrasse indirectly affect the cognitive performance of a damselfish through ectoparasite removal
Proceedings of the Royal Society B: Biological Sciences, 2018Co-Authors: Sandra A Binning, Simona Colosio, Derek Sun, Joanna Miest, Alexandra S. Grutter, Dominique G Roche, R. BsharyAbstract:Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, Labroides dimidiatus, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish ( Pomacentrus amboinensis) collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.
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cleaner fish Labroides dimidiatus discriminate numbers but fail a mental number line test
Animal Cognition, 2018Co-Authors: Zegni Triki, R. BsharyAbstract:Several species of primates, including humans, possess a spontaneous spatial mental arrangement (i.e. mental number line MNL) of increasing numbers or continuous quantities from left to right. This cognitive process has recently been documented in domestic chicken in a spatial–numerical task, opening the possibility that MNL is a cognitive capacity that has been conserved across vertebrate taxa. In this scenario, fish might possess the MNL as well. Here we investigated whether cleaner fish Labroides dimidiatus show evidence for MNL in two experiments. In Experiment I, we tested fish’s abilities in number discrimination, presenting simultaneously either small (2 vs 5) or large (5 vs 8) continuous quantities where one quantity was systematically rewarded. Experiment II used a protocol of an MNL task similar to the study on chickens. We trained cleaners with a target number (i.e. 5 elements), then we presented them with an identical pair of panels depicting either 2 elements or 8 elements, and we recorded their spontaneous choice for the left or right panel on each presentation. Cleaner fish showed high abilities in discriminating small and large numbers in Experiment I. Importantly, cleaners achieved this discrimination using numerical cues instead of non-numerical cues such as the cumulative surface area, density, and overall space. In contrast, cleaners did not allocate continuous quantities to space in Experiment II. Our findings suggest that cleaner fish possess numbering skills but they do not have an MNL. While similar studies on animals from various clades are needed to trace the evolution of MNL within vertebrates, our results suggest that this cognitive process might not be a capacity conserved across all vertebrate taxa.
Tetsuo Kuwamura - One of the best experts on this subject based on the ideXlab platform.
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testing the low density hypothesis for reversed sex change in polygynous fish experiments in Labroides dimidiatus
Scientific Reports, 2015Co-Authors: Tetsuo Kuwamura, Tatsuru Kadota, Shohei SuzukiAbstract:Hermaphroditism is ubiquitous among plants and widespread in the animal kingdom. It is an unsolved problem why reversed sex change has evolved in polygynous and protogynous reef fish. We have previously suggested that facultative monogamy occurs in low-density populations of polygynous species and that males that become single as a result of accidental mate loss may change sex when they meet larger males. In this study, to test this ‘low-density hypothesis’, we conducted field experiments with the coral reef fish Labroides dimidiatus in which a portion of females were removed to create a low-density situation. The ‘widowed’ males moved to search for a new mate when no male, female or juvenile fish migrated into their territories and paired with nearby single fish, whether male or female. Alternatively, males expanded their territories to take over the nearest pair whose male was much smaller. These results support our low-density hypothesis.
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Reversed sex change by widowed males in polygynous and protogynous fishes: female removal experiments in the field
Naturwissenschaften, 2011Co-Authors: Tetsuo Kuwamura, Shohei Suzuki, Tatsuru KadotaAbstract:Sex change, either protogyny (female to male) or protandry (male to female), is well known among fishes, but evidence of bidirectional sex change or reversed sex change in natural populations is still very limited. This is the first report on female removal experiments for polygnous and protogynous fish species to induce reversed sex change in the widowed males in the field. We removed all of the females and juveniles from the territories of dominant males in the cleaner wrasse Labroides dimidiatus (Labridae) and the rusty angelfish Centropyge ferrugata (Pomacanthidae) on the coral reefs of Okinawa. In both species, if new females or juveniles did not immigrate into the territories of the widowed males, some of them emigrated to form male–male pairs. When a male–male pair formed, the smaller, subordinate partner began to perform female sexual behaviours ( n = 4 in L. dimidiatus ; n = 2 in C. ferrugata ) and, finally, released eggs ( n = 1, respectively). Thus, the reversed sex change occurred in the widowed males according to the change of their social status. These results suggest that such female removal experiments will contribute to the discovery of reversed sex change in the field also in other polygnous and protogynous species.
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reversed sex change in the protogynous reef fish Labroides dimidiatus
Ethology, 2002Co-Authors: Tetsuo Kuwamura, Naomi Tanaka, Yasuhiro Nakashima, Kenji Karino, Yoichi SakaiAbstract:Protogynous hermaphroditism, or female-to-male sex change, is known for many reef fishes including wrasses (family Labridae) in which large males monopolize mating. When the dominant male disappears from a polygynous group, the largest female may change sex within a few weeks. Such social control of sex change was first documented in harems of the cleaner wrasse Labroides dimidiatus almost 30 yr ago. To examine whether change of social status would induce males of L. dimidiatus to perform reversed sex-change, we conducted experiments: (i) releasing single males near lone males whose mates have been removed in the field; and (ii) keeping two males in a tank. Smaller males changed back to females when they became subordinate: it took 53-77 d (n = 3) for them to complete gonadal sex change and release eggs in the aquarium. The male-male pairs performed spawning behavior, with the smaller male in the female role already 5-58 d before completion of gonadal sex change. This is the first report of reversed sex-change among protogynous wrasses. Moreover, we conducted another experiment, keeping a pair of a male and a larger female in a tank (n = 1). We found sex change by both mates, which has not been reported from any fishes. Thus, the sex of L. dimidiatus is strictly determined by social status whenever it changes after mate loss.
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Reversed Sex‐Change in the Protogynous Reef Fish Labroides dimidiatus
Ethology, 2002Co-Authors: Tetsuo Kuwamura, Naomi Tanaka, Yasuhiro Nakashima, Kenji Karino, Yoichi SakaiAbstract:Protogynous hermaphroditism, or female-to-male sex change, is known for many reef fishes including wrasses (family Labridae) in which large males monopolize mating. When the dominant male disappears from a polygynous group, the largest female may change sex within a few weeks. Such social control of sex change was first documented in harems of the cleaner wrasse Labroides dimidiatus almost 30 yr ago. To examine whether change of social status would induce males of L. dimidiatus to perform reversed sex-change, we conducted experiments: (i) releasing single males near lone males whose mates have been removed in the field; and (ii) keeping two males in a tank. Smaller males changed back to females when they became subordinate: it took 53-77 d (n = 3) for them to complete gonadal sex change and release eggs in the aquarium. The male-male pairs performed spawning behavior, with the smaller male in the female role already 5-58 d before completion of gonadal sex change. This is the first report of reversed sex-change among protogynous wrasses. Moreover, we conducted another experiment, keeping a pair of a male and a larger female in a tank (n = 1). We found sex change by both mates, which has not been reported from any fishes. Thus, the sex of L. dimidiatus is strictly determined by social status whenever it changes after mate loss.
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effect of changing harem on timing of sex change in female cleaner fish Labroides dimidiatus
Animal Behaviour, 2001Co-Authors: Yoichi Sakai, Masanori Kohda, Tetsuo KuwamuraAbstract:The cleaner wrasse Labroides dimidiatus has a haremic mating system. When the territorial dominant male disappears, the largest female of the harem changes sex and takes it over. During a 2.5-year field study on a high-density population, females sometimes temporarily intruded into neighbouring harems. Almost half of these females transferred to harems that they had frequently visited, suggesting that females may assess the social conditions of the harem during these visits. After the transfer, females increased in rank or escaped from similar-sized competitors in their former harem. As a result, such females could become the dominant male earlier than females that never changed harem. The females that transferred were reproductively active, but less fecund than females that did not. Their low spawning success as females may be offset by their earlier sex change to become a dominant male. We suggest that changing harems has developed as a life history tactic in high-density conditions where females, in a fish whose sex is socially controlled, compete to become male.
Sandra A Binning - One of the best experts on this subject based on the ideXlab platform.
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the performance of cleaner wrasse Labroides dimidiatus in a reversal learning task varies across experimental paradigms
PeerJ, 2018Co-Authors: Simon Gingins, Sharon Wismer, R. Bshary, Fanny Marcadier, Oceane Krattinger, Fausto Quattrini, Sandra A BinningAbstract: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.
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Cleaner wrasse indirectly affect the cognitive performance of a damselfish through ectoparasite removal
Proceedings of the Royal Society B: Biological Sciences, 2018Co-Authors: Sandra A Binning, Simona Colosio, Derek Sun, Joanna Miest, Alexandra S. Grutter, Dominique G Roche, R. BsharyAbstract:Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, Labroides dimidiatus, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish ( Pomacentrus amboinensis) collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.
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The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms
2017Co-Authors: Fanny Marcadier, Sharon Wismer, R. Bshary, Sandra A Binning, Oceane Krattinger, Fausto Quatttrini, Simon GinginsAbstract:Testing cognitive 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 discrimination 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 discrimination test. 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 cognitive performance, and might significantly influence the outcome of experiments. When designing the methodology for comparative cognitive tests, care should be taken to ensure that all groups understand and can respond to the relevant cue to avoid misinterpretations.
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Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches
PeerJ, 2015Co-Authors: Elena L.e.s. Wagner, Sharon Wismer, Dominique G Roche, Sandra A Binning, R. BsharyAbstract:Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus , was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.
Sharon Wismer - One of the best experts on this subject based on the ideXlab platform.
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the performance of cleaner wrasse Labroides dimidiatus in a reversal learning task varies across experimental paradigms
PeerJ, 2018Co-Authors: Simon Gingins, Sharon Wismer, R. Bshary, Fanny Marcadier, Oceane Krattinger, Fausto Quattrini, Sandra A BinningAbstract: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.
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The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms
2017Co-Authors: Fanny Marcadier, Sharon Wismer, R. Bshary, Sandra A Binning, Oceane Krattinger, Fausto Quatttrini, Simon GinginsAbstract:Testing cognitive 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 discrimination 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 discrimination test. 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 cognitive performance, and might significantly influence the outcome of experiments. When designing the methodology for comparative cognitive tests, care should be taken to ensure that all groups understand and can respond to the relevant cue to avoid misinterpretations.
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generalized rule application in bluestreak cleaner wrasse Labroides dimidiatus using predator species as social tools to reduce punishment
Animal Cognition, 2016Co-Authors: Sharon Wismer, Alexandra S. Grutter, R. BsharyAbstract:Generalized rule application promotes flexible behavior by allowing individuals to adjust quickly to environmental changes through generalization of previous learning. Here, we show that bluestreak ‘cleaner’ wrasse (Labroides dimidiatus) uses generalized rule application in their use of predators as social tools against punishing reef fish clients. Punishment occurs as cleaners do not only remove ectoparasites from clients, but prefer to feed on client mucus (constituting cheating). We tested for generalized rule application in a series of experiments, starting by training cleaners to approach one of two fish models in order to evade punishment (by chasing) from a ‘cheated’ client model. Cleaners learned this task only if the safe haven was a predator model. During consecutive exposure to pairs of novel species, including exotic models, cleaners demonstrated generalization of the ‘predators-are-safe-havens’ rule by rapidly satisfying learning criteria. However, cleaners were not able to generalize to a ‘one-of-two-stimuli-presents-a-safe-haven’ rule, as they failed to solve the task when confronted with either two harmless fish models or two predator models. Our results emphasize the importance of ecologically relevant experiments to uncover complex cognitive processes in non-human animals, like generalized rule learning in the context of social tool use in a fish.
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Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches
PeerJ, 2015Co-Authors: Elena L.e.s. Wagner, Sharon Wismer, Dominique G Roche, Sandra A Binning, R. BsharyAbstract:Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus , was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.
