Sensitivity Differences in Fish Offer Near-Infrared Vision as an Adaptable Evolutionary Trait

Abstract

Near-infrared (NIR) light constitutes an integrated part of solar radiation. The principal ability to sense NIR under laboratory conditions has previously been demonstrated in fish. The availability of NIR in aquatic habitats, and thus its potential use as a cue for distinct behaviors such as orientation and detection of prey, however, depends on physical and environmental parameters. In clear water, blue and green light represents the dominating part of the illumination. In turbid waters, in contrast, the relative content of red and NIR radiation is enhanced, due to increased scattering and absorption of short and middle range wavelengths by suspended particles and dissolved colored materials. We have studied NIR detection thresholds using a phototactic swimming assay in five fish species, which are exposed to different NIR conditions in their natural habitats. Nile and Mozambique tilapia, which inhabit waters with increased turbidity, displayed the highest spectral sensitivity, with thresholds at wavelengths above 930 nm. Zebrafish, guppy and green swordtail, which prefer clearer waters, revealed significantly lower thresholds of spectral sensitivity with 825–845 nm for green swordtail and 845–910 nm for zebrafish and guppy. The present study revealed a clear correlation between NIR sensation thresholds and availability of NIR in the natural habitats, suggesting that NIR vision, as an integral part of the whole spectrum of visual abilities, can serve as an evolutionarily adaptable trait in fish.

Cyp27c1 Red-Shifts the Spectral Sensitivity of Photoreceptors by Converting Vitamin A1 into A2

“…We therefore developed an assay to measure changes in swimming behavior in response to light of various wavelengths (Figure 5A-C). When exposed to a directional light source, adult zebrafish display a positive phototactic response (Movies S1 and S2) [32]. We hypothesized that TH-treated wild-type fish would have a stronger phototactic response to near-infrared light than cyp27c1 Δ1/Δ3 mutants due to the vitamin A 2 -induced red-shift in spectral sensitivity.…”

Gaze stabilisation behaviour is anisotropic across visual field locations in zebrafish

“…However, time-lapse frontal microscopy images ( Methods ) ruled this out, since for both upside-up and upside-down embedding the eyes were inclined by an average of about 4 degrees towards the dorsum (3.5±1.0° for the left eye, 4.9±0.8° for the right eye, mean ± s.e.m., S3 Fig ). We also tested the influence of camera and infrared light (840 nm) positions ( S1g, Fig ) – which in either case should have been invisible to the fish (42) – and found that they could indeed not explain the observed differences. As the body-centred preferred location in upside-down embedded fish flipped from slightly dorsal to slightly ventral ( S1j Fig ), and thus remained virtually unchanged in environmental coordinates, optokinetic stimulus location preference appears to be related to the behavioural relevance of these stimulus positions, and cannot merely be caused by retinal feedforward circuitry.…”

“…We also tested the influence of camera and infrared light (840 nm) positions ( S1g-j Fig, S1k-j Fig , Fig. 4) – which in either case should have been invisible to the fish (Shcherbakov et al, 2013) – and found that they could indeed not explain the observed differences. As the body-centred preferred location in upside-down embedded fish flipped from slightly dorsal to slightly ventral ( S1j Fig ), and thus remained virtually unchanged in environmental coordinates, optokinetic stimulus location preference appears to be related to the behavioural relevance of these stimulus positions, and cannot merely be caused by retinal feedforward circuitry.…”

Behaviour of the plathelminth Symsagittifera roscoffensis under different light conditions and the consequences on the symbiotic algae Tetraselmis convolutae

“…Nevertheless, perception of wavelengths that are not dominant in a specific depth may be useful for the detection of fluorescent light, e.g. for communication, which has been observed in different fish species (Michiels et al, 2008;Shcherbakov et al, 2013Shcherbakov et al, , 2012.…”