Visual pigments, oil droplets, lens, and cornea characterization in the whooping crane (Grus americana)

Journal of Experimental Biology
University of South Dakota, University of Maryland Baltimore County
By: , and 

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Abstract

Vision has been investigated in many species of birds, but few studies have considered the visual systems of large birds and the particular implications of large eyes and long-life spans on visual system capabilities. To address these issues we investigated the visual system of the whooping crane, Grus americana (Gruiformes: Gruidae). G. americana (an endangered species) is one of only two North American crane species and represents a large, long-lived bird where ultraviolet sensitivity may be degraded by chromatic aberrations and entrance of ultraviolet light into the eye could be detrimental to retinal tissues. To investigate the whooping crane visual system we used microspectrophotometry to determine the absorbance spectra of retinal oil droplets and to investigate if the ocular media (i.e., the lens and cornea) absorbs UV light. In vitro expression and reconstitution was used to determine the absorbance spectra of rod and cone visual pigments. The rod visual pigments had wavelengths of peak absorbance (λmax) at 500 nm, while the cone visual pigments λmax values were determined to be 404 nm (SWS1), 450 nm (SWS2), 499 nm (RH2), and 561 nm (LWS), similar to other characterized bird visual pigment absorbance values. The oil droplet cutoff wavelength (λcut) values similarly fell within ranges recorded from other avian species: 576 nm (R-type), 522 nm (Y-type), 506 nm (P-type), and 448 nm (C-type). We confirm that G. americana has a violet-sensitive visual system, although based on the λmax of the SWS1 visual pigment (404 nm) may also have some ability for UV sensitivity.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Visual pigments, oil droplets, lens, and cornea characterization in the whooping crane (Grus americana)
Series title Journal of Experimental Biology
DOI 10.1242/​jeb.108456
Volume 217
Issue 21
Year Published 2014
Language English
Publisher Society for Experimental Biology
Publisher location London, England
Contributing office(s) Patuxent Wildlife Research Center
Description 8 p.
First page 3883
Last page 3890
Online Only (Y/N) N
Additional Online Files (Y/N) N