Vision in the grass goby,Zosterisessor ophiocephalus(Teleostei, Gobiidae): A morphological and behavioural study

Abstract

The visual abilities of Zosterisessor ophiocephalus, an ambushing predator inhabiting the intertidal seagrass meadows of lagoons, were studied by morphological and behavioural methods. In its retina, a high number of rods, double and single cones packed in a square mosaic were found, together with the retinomotor response involving the pigment granules and both kinds of photoreceptors. The retinal topography was made by analysing the cone density and density of cells in the ganglion cell layer, and it revealed the area centralis in the dorso-temporal region of the retina. ) on its visual abilities for prey detection was found by comparing the detection and capture efficiencies and the detection and capture distance. A preference for larger food targets was observed. Two capture strategies are described: fast direct and slower hopping capture, the latter exhibited with higher frequency under dim light. Histological visual acuity was 7' and behavioural visual acuity was 15'. The morphological and behavioural studies showed that Z. ophiocephalus can use vision for feeding in bright and dim light conditions, but it probably feeds more at dusk to avoid predators.KEY WORDS: Retina -Retinal topography -Light intensity and behaviour -Visual acuity -Lagoon. ACKNOWLEDGEMENTS

Behavioural and anatomical measures of visual acuity in first-feeding Yellowtail Kingfish (Seriola lalandi) larvae

“…Both methods have shown that visual acuity improves rapidly during early development (Neave 1984;Wanzenböck and Schierner 1989;Pankhurst et al 1993;Job and Bellwood 1996), corresponding to a progressive increase in visual capability. However estimates of acuity stemming from behavioural studies are consistently lower than those obtained from anatomical studies of photoreceptor density (Miller et al 1993;Higgs and Fuiman 1996;Job and Bellwood 1996;Ota et al 1999). Although many studies have determined anatomical visual acuity for larval fish (Neave 1984;Margulies 1989;Mas-Riera 1991;Pankhurst et al 1993;Shand 1994;Helvik and Karlsen 1996;Pankhurst and Eagar 1996;Chai et al 2006), studies that pair anatomical measures with behavioural estimates are limited to a few species (Miller et al 1993;Pankhurst 1994;Higgs and Fuiman 1996;Job and Bellwood 1996;Ota et al 1999).…”

“…However estimates of acuity stemming from behavioural studies are consistently lower than those obtained from anatomical studies of photoreceptor density (Miller et al 1993;Higgs and Fuiman 1996;Job and Bellwood 1996;Ota et al 1999). Although many studies have determined anatomical visual acuity for larval fish (Neave 1984;Margulies 1989;Mas-Riera 1991;Pankhurst et al 1993;Shand 1994;Helvik and Karlsen 1996;Pankhurst and Eagar 1996;Chai et al 2006), studies that pair anatomical measures with behavioural estimates are limited to a few species (Miller et al 1993;Pankhurst 1994;Higgs and Fuiman 1996;Job and Bellwood 1996;Ota et al 1999). In addition, behavioural studies have also shown that improvements in acuity are accompanied by lateral expansion of the visual field (Job and Bellwood 1996;Browman and O'Brien 1992a, b;Cobcroft and Pankhurst 2006), and reduced scotopic thresholds (Fuiman and Delbos 1998).…”

Fine arrangement of photoreceptors in retina and mode of vision in beaked sea snake,Enhydrina schistosa(Daudin, 1803) (Reptilia: Hydrophiidae)

“…In spite of the non-protractile myeloid, the outer segments of cones were surrounded by pigment bar granules which occur in response to light intensity as a part of the retinomotor response (Figure 3b). In fishes, various sizes of eyes, the position of the eye on the head, the structure of the cornea (thickness and curvature) and lens (shape and diameter), morphology of the retina, the visual neural pathway, types of cone cells, eye movement and retinomotor response are greatly influenced by water depth, turbidity, flow speed, temperature, feeding habits and food availability, bringing about different levels of visual fields and acuity (Ota et al 1999;Collin & Shand 2003). As sea snakes live, feed and in some species reproduce in the open sea (E. schistosa), the presence of a single type of photoreceptors, a motionless eye, the absence of protractile myoid and spectacle covering, make it difficult to expect the visual sense to be very effective and confront ecological factors that may affect the spectral tuning of snake visual pigments (Hart et al 2012).…”

Retinal ganglion cell topography and spatial resolution estimation in the Japanese tree frog Hyla japonica (Günther, 1859)

“…Some authors used behavioral cues (e.g. Entsu et al 1992;Ota, 1999), whereas others relied upon physiological techniques (Bartol et al 2002). In structural research, spatial resolving power is usually determined from the spatial arrangement of photoreceptors and/or retinal ganglion cells (GCs) (e.g.…”