The Retina of Five Atherinomorph Teleosts: Photoreceptors, Patterns and Spectral Sensitivities

Abstract

We investigated the spectral and morphological features of the photoreceptors of five atherinomorph teleosts, representing two different orders, and with different life styles and habitats, the Beloniformes and Atheriniformes. The retinae of Belone belone (Belonidae), Dermogenys pusillus (Hemiramphidae), Atherina boyeri (Atherinidae), Marosatherina ladigesi (Telmatherinidae), and Melanotaenia maccullochi (Melanotaeniidae) were examined by light and electron microscopy and microspectrophotometry. In addition to rods, five morphologically different cone types were identified: short, intermediary and long single cones, and double cones which are arranged in distinct specific mosaics. Sporadically, triple cones were also found. Double cones were longer-wave-sensitive, but no general correlation between single cone morphology and spectral sensitivity could be demonstrated. The rods had λ_max close to 506–509 nm. The λ_max of cone visual pigments ranged from about 368 nm to 578 nm. Ultraviolet-sensitive single cones were present in the three freshwater species, M. ladigesi, M. maccullochi and D. pusillus and three spectrally distinct short-wave-sensitive single cone classes were identified in M. maccullochi. In M. ladigesi, spectral sensitivity varied among individuals due to varying rhodopsin/porphyropsin mixtures. In D. pusillus and M. maccullochi polymorphism of the longer-wave cone pigments might occur. These findings are discussed with respect to phylogeny, photic habitat, behavior and feeding habits.

Predation is associated with variation in colour pattern, but not body shape or colour reflectance, in a rainbowfish (Melanotaenia australis)

“…Although predators may have vision in the ultraviolet, in water, ultraviolet light is readily scattered over distance because of its short wavelength. Thus, because potential predators are typically further away than conspecifics, ultraviolet‐based patterns may be less visible to predators but still useful as a means of signalling among conspecifics (Endler 1991; Reckel et al. 2002).…”

Intraretinal variability and specialization of cones in Japanese anchovy (Engraulis japonicus, Engraulidae)

“…Different distribution patterns of the cone visual pigments across the retina have been found in many fish species (Reckel et al, ; Temple et al, ; Temple, ; Owens et al, ). Such intraretinal variation was confirmed for the European anchovy (Zueva and Govardovskii, ) and later for the Japanese anchovy (Kondrashev et al, ).…”

Spectral sensitivity of the two-spotted gobyGobiusculus flavescens(Fabricius): a physiological and behavioural study

“…Absorbance spectra of the visual pigments of cones and rods can be measured directly by microspectrophotometry (Bowmaker, 1995) or inferred from electrophysiology (Parkyn and Hawryshyn, 2000;Whitmore and Bowmaker, 1989) and can give indications of spectral sensitivity and the potential for colour vision (Barry and Hawryshyn, 1999;Cameron, 2002). Histological studies can reveal the distribution of the various photoreceptor classes (Reckel et al, 2002;Van der Meer et al, 1995), complementing the physiological measurements of spectral sensitivity and providing estimations of visual acuity (Fritsches et al, 2003;Shand, 1997). However, none of these methods can define visual performance, which can only be determined by behavioural experiments (Douglas and Hawryshyn, 1990;White et al, 2004) involving either innate behaviours such as the optomotor response (Krauss and Neumeyer, 2003;Schaerer and Neumeyer, 1996) or behavioural activities such as feeding strategies (Job and Shand, 2001;Utne-Palm, 2002).…”