Visual pigments, oil droplets, ocular media and cone photoreceptor distribution in two species of passerine bird: the blue tit ( Parus caeruleus L.) and the blackbird ( Turdus merula L.)

SUMMARY We report microspectrophotometric (MSP) data for the visual pigments and oil droplets of 17 species of Caribbean anoline lizard known to live in differing photic habitats and having distinctly different dewlap colors. The outgroup Polychrus marmoratus was also examined to gain insight into the ancestral condition. Except for Anolis carolinensis, which is known to use vitamin A2 as its visual pigment chromophore, all anoline species examined possessed at least four vitamin-A1-based visual pigments with maximum absorbance (λmax) at 564, 495,455 and 365 nm. To the previously reported visual pigments for A. carolinensis we add an ultraviolet-sensitive one withλ max at 365 nm. Five common classes of oil droplet were measured, named according to apparent color and associated with specific cone classes — yellow and green in long-wavelength-sensitive (LWS) cones,green only in medium-wavelength-sensitive (MWS) cones and colorless in short-wavelength-sensitive (SWS) and ultraviolet-sensitive (UVS) cones. MSP data showed that the colorless droplet in the SWS cone had significant absorption between 350 and 400 nm, while the colorless droplet in the UVS cone did not. The pattern for Polychrus marmoratus was identical to that for the anoles except for the presence of a previously undescribed visual cell with a rod-like outer segment, a visual pigment with a λmaxof 497 nm and a colorless oil droplet like that in the UVS cones. These findings suggest that anoline visual pigments, as far as they determine visual system spectral sensitivity, are not necessarily adapted to the photic environment or to the color of significant visual targets (e.g. dewlaps).

Download Full-text

Visual pigments, oil droplets and cone photoreceptor distribution in the european starling (Sturnus vulgaris)

Journal of Experimental Biology ◽

10.1242/jeb.201.9.1433 ◽

1998 ◽

Vol 201 (9) ◽

pp. 1433-1446 ◽

Cited By ~ 11

Author(s):

N S Hart ◽

J C Partridge ◽

I C Cuthill

Keyword(s):

Visual Pigment ◽

Sturnus Vulgaris ◽

European Starling ◽

Visual Pigments ◽

Double Cone ◽

Temporal Region ◽

Oil Droplets ◽

Tetrazolium Chloride ◽

Oil Droplet ◽

Single Cone

Microspectrophotometric measurements of retinal photoreceptors from the European starling (Sturnus vulgaris) revealed four classes of single cone, containing visual pigments with wavelengths of maximum absorbance (<IMG src="/images/symbols/lambda.gif" WIDTH="8" HEIGHT="12" ALIGN="BOTTOM" NATURALSIZEFLAG= "3">max) at 563, 504, 449 and close to 362 nm. The two longer-wave-sensitive single cones contained brightly coloured oil droplets which cut off light below 572 and 514 nm, respectively. The 449 nm <IMG src="/images/symbols/lambda.gif" WIDTH="8" HEIGHT="12" ALIGN="BOTTOM" NATURALSIZEFLAG="3">max pigment was associated with a 'colourless' oil droplet with peak measured absorptance below 400 nm. The ultraviolet-sensitive visual pigment was paired with a transparent oil droplet which showed no significant absorption above 350 nm. A single class of double cone was identified, both members of which contained the longwave-sensitive (<IMG src="/images/symbols/lambda.gif" WIDTH="8" HEIGHT= "12" ALIGN="BOTTOM" NATURALSIZEFLAG="3">max 563 nm) visual pigment. The principal member of the double cone contained an oil droplet with a topographically variable cut-off wavelength below 471 nm; the oil droplet found in the accessory member was only measured in the ventral retina and displayed three distinct peaks of absorption at approximately 430, 450 and 480 nm. Rod photoreceptors had a <IMG src="/images/symbols/lambda.gif" WIDTH="8" HEIGHT="12" ALIGN="BOTTOM" NATURALSIZEFLAG="3">max at 503 nm. A new polynomial for fitting visual pigment templates to ultraviolet-sensitive visual pigment data is given. Topographic density measurements of the different cone classes were made using Nitroblue-tetrazolium chloride to label selectively bleached photoreceptors. The two classes of shortwave-sensitive single cone were more abundant in the dorsal retina, and longwave-sensitive single cones were notably less abundant in the dorso-temporal region of the retina, which subserves binocular vision.

Download Full-text

The spectral transmission of ocular media suggests ultraviolet sensitivity is widespread among mammals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.2995 ◽

2014 ◽

Vol 281 (1780) ◽

pp. 20132995 ◽

Cited By ~ 61

Author(s):

R. H. Douglas ◽

G. Jeffery

Keyword(s):

Energy Level ◽

Visual Pigment ◽

High Spatial Resolution ◽

Mammalian Species ◽

Visual Pigments ◽

Spectral Transmission ◽

Tree Shrews ◽

Uv Sensitivity ◽

Ultraviolet Sensitivity ◽

Ocular Media

Although ultraviolet (UV) sensitivity is widespread among animals it is considered rare in mammals, being restricted to the few species that have a visual pigment maximally sensitive ( λ max ) below 400 nm. However, even animals without such a pigment will be UV-sensitive if they have ocular media that transmit these wavelengths, as all visual pigments absorb significant amounts of UV if the energy level is sufficient. Although it is known that lenses of diurnal sciurid rodents, tree shrews and primates prevent UV from reaching the retina, the degree of UV transmission by ocular media of most other mammals without a visual pigment with λ max in the UV is unknown. We examined lenses of 38 mammalian species from 25 families in nine orders and observed large diversity in the degree of short-wavelength transmission. All species whose lenses removed short wavelengths had retinae specialized for high spatial resolution and relatively high cone numbers, suggesting that UV removal is primarily linked to increased acuity. Other mammals, however, such as hedgehogs, dogs, cats, ferrets and okapis had lenses transmitting significant amounts of UVA (315–400 nm), suggesting that they will be UV-sensitive even without a specific UV visual pigment.

Download Full-text

1D1515 Determinant of rapid phosphorylation of visual pigments in cone photoreceptor cells

Seibutsu Butsuri ◽

10.2142/biophys.42.s26_4 ◽

2002 ◽

Vol 42 (supplement2) ◽

pp. S26

Author(s):

S. Tachibanaki ◽

S. Tsushima ◽

Y. Shimauchi-Matsukawa ◽

S. Kawamura

Keyword(s):

Photoreceptor Cells ◽

Visual Pigments ◽

Cone Photoreceptor

Download Full-text