The eyes of two talitrid amphipods: differences in structure may reflect different behaviours

Mezzetti, M. C.; Gambineri, Simone; Scapini, Felicita

doi:10.1080/10236241003786865

Cited by 1 publication

(4 citation statements)

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“…Shifting of spectral sensitivity could also result from vesicles overlying the ommatidia of talitrids (e.g. Mezzetti et al, 2010), although such vesicles have yet to be reported for T. longicornis, and, if they are present, their spectral properties are unknown. Two peaks are also evident in the behavioral response spectrum for phototaxis, yet the behavioral peaks (440 to 520nm and 560 to 580nm) are shifted to longer wavelengths than the electrophysiological measure of sensitivity.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, a multiple-pigment visual system might be common in talitrids, and further comparative studies of proximate and ultimate aspects of visual spectral sensitivity are warranted, given differences in talitrid ecology among species and known morphological diversity in eye morphology (e.g. Mezzetti et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Mezzetti and colleagues (Mezzetti et al, 2010) recently reported differences in eye morphology between Talorchestia spinifera and Talitrus saltator that might be related to differences in habitat and how their eyes are used in orientation. Talorchestia spinifera, which lives lower intertidally and is less nocturnal than Talitrus saltator, has more extensive interommatidial cells and, probably, a less sensitive eye.…”

Section: Introductionmentioning

confidence: 99%

“…Talorchestia spinifera, which lives lower intertidally and is less nocturnal than Talitrus saltator, has more extensive interommatidial cells and, probably, a less sensitive eye. Furthermore, both species have vesicles between each set of photoreceptors and the overlying lens of currently unknown function, but it has been suggested that the distinct horizontal alignment of vesicles across the eye in Talorchestia spinifera plays a role in seaward orientation (Mezzetti et al, 2010). Preliminary electrophysiological studies (Ugolini et al, 1996) and several behavioral studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Visual physiology underlying orientation and diel behavior in the sand beach amphipod Talorchestia longicornis

Cohen

Cronin

Lessios

et al. 2010

Journal of Experimental Biology

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SUMMARYTalitrid amphipods employ vision for zonal recovery behaviors on sand beaches and for entraining circadian activity rhythms. Using a hierarchy of methods, we examined visual spectral and response-intensity functions in Talorchestia longicornis, a species in which orientation and rhythm entrainment are wavelength-specific behaviors. Microspectrophotometry, electroretinogram recording and behavioral assays were used to determine visual pigments, retinal spectral sensitivity and wholeanimal spectral responsivity, respectively. Diel changes in absolute sensitivity were also investigated at retinal and whole-animal levels. Two receptor spectral classes were identified, with values for visual pigment  max of 427 and 518nm. Retinal spectral sensitivity varied with electrode position along the distal-proximal axis. Chromatic adaptation of distal and proximal photoreceptors resulted in sensitivity peaks at 430 and 522nm, respectively. In accordance with identified visual pigments and spectral sensitivity, T. longicornis photobehavioral responsivity covered a broad range (420-580nm). Collectively, a dualpigment visual system underlies wavelength-specific behavior in T. longicornis, with the short-wavelength pigment likely to be localized in the distal R5 retinular cell. While response-intensity functions did not change over the diel cycle at the retinal level, behavioral photoresponsiveness varied between day and night. At a wavelength used by T. longicornis for celestial orientation (420nm), photobehavior was heightened at night, potentially aiding in nocturnal orientation. By contrast, at a wavelength used to entrain its circadian rhythm (520nm) and for routine visual tasks, photobehavior was heightened during the day, and spectral sensitivity matched to the twilight spectrum, facilitating crepuscular vision and entrainment by irradiance at sunrise and sunset.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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