Journal of the Marine Biological Association of the United Kingdom

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Journal of the Marine Biological Association of the United Kingdom (2009), 89:119-129 Cambridge University Press
Copyright © Marine Biological Association of the United Kingdom 2009
doi:10.1017/S0025315408002440

Research Article

Spectral sensitivity, visual pigments and screening pigments in two life history stages of the ontogenetic migrator Gnathophausia ingens


Tamara M. Franka1 c1, Megan Portera2 and Thomas W. Cronina2

a1 Harbor Branch Oceanographic Institute at FAU, 5600 US 1 North, Fort Pierce, Florida 34946 USA
a2 Department of Biological Sciences, University of Maryland, Baltimore County Campus, 1000 Hilltop Circle, Baltimore, MD 21250
Article author query
frank tm [PubMed]  [Google Scholar]
porter m [PubMed]  [Google Scholar]
cronin tw [PubMed]  [Google Scholar]

Abstract

Spectral sensitivity, visual pigment absorbance spectra and visual pigment opsin sequences were examined in younger shallow-living and older deep-living instars of the ontogenetically migrating lophogastrid Gnathophausia ingens. Spectral sensitivity measurements from dark adapted eyes and microspectrophotometric measurements of the rhabdom indicate maximal sensitivity for long wavelength (495–502 nm) light in both life history stages, but the younger instars are significantly more sensitive to near-ultraviolet light than the adults. Both life history stages express the same two opsins, indicating that there is no ontogenetic change in visual pigment complement between life history stages. Chromatic adaptation shifted the spectral sensitivity maximum to significantly longer wavelengths in both age-classes, but a distinct secondary short wavelength peak is visible only in the younger instars. These shifts appear to be due to the presence of migrating screening pigments, which are probably vestigial in the deep-living adults. Anomalies in the response waveforms under chromatic adaptation also apparently result from filtering by screening pigments, but via an unknown mechanism.

(Received January 04 2008)

(Accepted May 31 2008)

Keywordsdeep-sea; visual ecology; crustacean

Correspondence:

c1 Correspondence should be addressed to: T.M. Frank, Harbor Branch Oceanographic Institution at FAU, 5600 US 1 North, Fort Pierce, Florida 34946 USA email: tfrank3@hboi.fau.edu