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Many animals rely on their visual systems to detect, locate or discriminate information in their environment. Environmental ‘visual noise’, however, may interfere with an animal’s ability to detect visual information, affecting decision-making processes. A ubiquitous form of visual noise in aquatic environments is caustic flicker; moving light patterns caused by the refraction of light through surface waves. While caustics impair the ability of fishes to detect prey, the impacts of caustics on the ability of non-vertebrates to target prey remains untested. In the present study, we ask whether the hunting success of the common cuttlefish (Sepia officinalis) is affected by the presence of caustic flicker. To do this, we tested if both the spatial (definition) and temporal (speed) components of caustic flicker affected the ability of cuttlefish to detect and catch a common prey, the brown shrimp (Crangon crangon). Neither the spatial nor temporal components of caustic flicker affected the detection latency or the capture time of prey. Moreover, cuttlefish did not adapt their hunting behaviour, including their approach speed, movement bouts, attack distance or angle, as a function of caustic flicker. Our results show that visual noise from caustic flicker does not affect the ability of cuttlefish to hunt their prey or their hunting behaviour. We provide multiple explanations, including the role of polarization vision, for why dynamic illumination does not appear to impact the visual sensory processing of cuttlefish.

Gathering information from the environment allows animals to make informed behavioural decisions, with individuals sampling information either privately or via social cues from group members. Environmental noise, however, may disrupt the ability of animals to gather information in their environment. Therefore, social interactions could be disrupted by environmental noise, or adapted to mitigate the costs associated with compromised perception in noisy environments. Here we tested whether the presence of water caustics, a natural form of visual noise prevalent within shallow aquatic habitats, affects the social decisions of shoaling fish. In a classic experimental paradigm, individual three-spined sticklebacks, Gasterosteus aculeatus, were given a choice between two conspecific shoals differing in size while immersed in different levels of visual noise. Fish showed greater social attraction towards conspecifics as noise levels increased, measured by a reduction in the distance they maintained from others. While sticklebacks only showed clear preferences for groups that had at least four more members than another group, there was no evidence that visual noise level influenced fish’s preference to associate with these larger shoals, nor did it change the preferences for other shoal sizes. Our findings suggest that, at the group sizes tested, visual noise increases individual stickleback’s social attraction towards conspecifics, but does not affect their decision to associate with the larger of two groups. Such changes to social behaviour may reflect the consequences of having a reduced ability to sample private, but not social, information in noisy environments.

Gathering information from the environment allows animals to make informed behavioural decisions, with individuals sampling information either privately or via social cues from group members. Environmental noise, however, may disrupt the ability of animals to gather information in their environment. Therefore, social interactions could be disrupted by environmental noise, or adapted to mitigate the costs associated with compromised perception in noisy environments. Here we tested whether the presence of water caustics, a natural form of visual noise prevalent within shallow aquatic habitats, affects the social decisions of shoaling fish. In a classic experimental paradigm, individual three-spined sticklebacks, Gasterosteus aculeatus, were given a choice between two conspecific shoals differing in size while immersed in different levels of visual noise. Fish showed greater social attraction towards conspecifics as noise levels increased, measured by a reduction in the distance they maintained from others. While sticklebacks only showed clear preferences for groups that had at least four more members than another group, there was no evidence that visual noise level influenced fish’s preference to associate with these larger shoals, nor did it change the preferences for other shoal sizes. Our findings suggest that, at the group sizes tested, visual noise increases individual stickleback’s social attraction towards conspecifics, but does not affect their decision to associate with the larger of two groups. Such changes to social behaviour may reflect the consequences of having a reduced ability to sample private, but not social, information in noisy environments.