1.Many “client” coral reef fishes have their ectoparasites removed by the “cleaner” wrasseLabroides dimidiatus in mutualistic interactions.Clients regularly receiving cleaning services reportedly benefit from increased growth and cognitive performance, but the underlying physiological changes that covary with such benefits are unknown.

Data and analysis script for: Norin et al (in prep) Predator presence affects activity patterns but not food consumption or growth of juvenile corkwing wrasse (Symphodus melops)
Please see readme file.
Abstract: Indirect effects of predators can manifest themselves as changes in prey behaviour and physiology. Reduced prey activity is a common behavioural response to predation risk, generally resulting in reduced foraging and growth. Given that digestion requires energy, it has been suggested that prey will choose to eat smaller meals under predation risk to reserve a larger portion of the aerobic metabolic scope they have available for energetically demanding tasks more critical than digestion, such asescape. To test this prediction, we quantified food consumption and growth of juvenile corkwing wrasses (Symphodus melops) over 11 days in the presence or absence of a predator (Atlantic cod, Gadus morhua). We then quantified behaviour and food consumption of the same wrasses in behavioural arenas with a predator present. All food consumption data were examined in the context of the aerobic scope that would have been available during the digestive period. Overall, there was no effect ofpredator exposure on food consumption or growth, yet predator-exposed wrasses were more consistent in their daily food consumption, lending some support to our prediction of prey bet-hedging on meal size under predation risk. The lack of a clear pattern may have resulted from a relatively low percentage of aerobic scope (~20-27%) beingoccupied by digestion, such that fish retained ample aerobic scope for activities other than digestion. In the subsequent behavioural trials, predator-exposed wrasses weremore active and spent more time near the cod than predator-naïve wrasses, suggesting the former had habituated to predation threat and were more risk-taking.Our results highlight the complex and often counter-intuitive effects that predator presence can have on prey populations beyond direct consumption.

Data and analysis script for: Norin et al (in prep) Predator presence affects activity patterns but not food consumption or growth of juvenile corkwing wrasse (Symphodus melops)
Please see readme file.
Abstract: Indirect effects of predators can manifest themselves as changes in prey behaviour and physiology. Reduced prey activity is a common behavioural response to predation risk, generally resulting in reduced foraging and growth. Given that digestion requires energy, it has been suggested that prey will choose to eat smaller meals under predation risk to reserve a larger portion of the aerobic metabolic scope they have available for energetically demanding tasks more critical than digestion, such asescape. To test this prediction, we quantified food consumption and growth of juvenile corkwing wrasses (Symphodus melops) over 11 days in the presence or absence of a predator (Atlantic cod, Gadus morhua). We then quantified behaviour and food consumption of the same wrasses in behavioural arenas with a predator present. All food consumption data were examined in the context of the aerobic scope that would have been available during the digestive period. Overall, there was no effect ofpredator exposure on food consumption or growth, yet predator-exposed wrasses were more consistent in their daily food consumption, lending some support to our prediction of prey bet-hedging on meal size under predation risk. The lack of a clear pattern may have resulted from a relatively low percentage of aerobic scope (~20-27%) beingoccupied by digestion, such that fish retained ample aerobic scope for activities other than digestion. In the subsequent behavioural trials, predator-exposed wrasses weremore active and spent more time near the cod than predator-naïve wrasses, suggesting the former had habituated to predation threat and were more risk-taking.Our results highlight the complex and often counter-intuitive effects that predator presence can have on prey populations beyond direct consumption.

1.Many “client” coral reef fishes have their ectoparasites removed by the “cleaner” wrasseLabroides dimidiatus in mutualistic interactions.Clients regularly receiving cleaning services reportedly benefit from increased growth and cognitive performance, but the underlying physiological changes that covary with such benefits are unknown.

Here, we provide evidence that intraspecific variation in the strategic sophistication of “cleaner” fish Labroides dimidiatus in laboratory experiments correlates with small scale / between-years variation in their intra- and interspecific social environment.

Here, we provide evidence that intraspecific variation in the strategic sophistication of “cleaner” fish Labroides dimidiatus in laboratory experiments correlates with small scale / between-years variation in their intra- and interspecific social environment.

Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates on the heads of Atlantic cod (Gadus morhua) and quantified whether local brain cooling increased whole-organism acute upper thermal tolerance. Brain cooling reduced brain temperature by 2-6°C below ambient water and increased thermal tolerance by 0.5 and 0.6°C on average relative to instrumented and uninstrumented controls, respectively, suggesting that direct thermal effects on brain neurons may contribute to setting upper thermal limits in fish. However, the improvement in thermal tolerance with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g., failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance.

The physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that loss of motor function observed as a loss of equilibrium during an acute thermal challenge is due to direct thermal effects on brain neuronal function. To test this hypothesis, we mounted cooling plates on the head of Atlantic cod (Gadus morhua) and quantified whether local cooling of the brain increased whole-organism upper thermal tolerance (CT_max). Brain cooling reduced brain temperature by 2–6°C and increased CT_max by 0.5–0.7°C relative to instrumented and uninstrumented controls, suggesting that direct thermal effects on brain neurons might contribute to setting upper thermal limits in fish. However, the improvement in CT_max with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g. failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance in fishes.

Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates on the heads of Atlantic cod (Gadus morhua) and quantified whether local brain cooling increased whole-organism acute upper thermal tolerance. Brain cooling reduced brain temperature by 2-6°C below ambient water and increased thermal tolerance by 0.5 and 0.6°C on average relative to instrumented and uninstrumented controls, respectively, suggesting that direct thermal effects on brain neurons may contribute to setting upper thermal limits in fish. However, the improvement in thermal tolerance with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g., failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance.

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.