The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.

BACKGROUND: For many bird species, vision is the primary sensory modality used to locate and assess food items. The health and spectral sensitivities of the avian visual system are influenced by diet-derived carotenoid pigments that accumulate in the retina. Among wild House Finches (Carpodacus mexi...

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Main Authors: Matthew B Toomey, Kevin J McGraw
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3126843?pdf=render
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spelling doaj-70c671306e834ad7b9d3f6f0215ce5c92020-11-25T01:25:23ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0166e2165310.1371/journal.pone.0021653The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.Matthew B ToomeyKevin J McGrawBACKGROUND: For many bird species, vision is the primary sensory modality used to locate and assess food items. The health and spectral sensitivities of the avian visual system are influenced by diet-derived carotenoid pigments that accumulate in the retina. Among wild House Finches (Carpodacus mexicanus), we have found that retinal carotenoid accumulation varies significantly among individuals and is related to dietary carotenoid intake. If diet-induced changes in retinal carotenoid accumulation alter spectral sensitivity, then they have the potential to affect visually mediated foraging performance. METHODOLOGY/PRINCIPAL FINDINGS: In two experiments, we measured foraging performance of house finches with dietarily manipulated retinal carotenoid levels. We tested each bird's ability to extract visually contrasting food items from a matrix of inedible distracters under high-contrast (full) and dimmer low-contrast (red-filtered) lighting conditions. In experiment one, zeaxanthin-supplemented birds had significantly increased retinal carotenoid levels, but declined in foraging performance in the high-contrast condition relative to astaxanthin-supplemented birds that showed no change in retinal carotenoid accumulation. In experiments one and two combined, we found that retinal carotenoid concentrations predicted relative foraging performance in the low- vs. high-contrast light conditions in a curvilinear pattern. Performance was positively correlated with retinal carotenoid accumulation among birds with low to medium levels of accumulation (∼0.5-1.5 µg/retina), but declined among birds with very high levels (>2.0 µg/retina). CONCLUSION/SIGNIFICANCE: Our results suggest that carotenoid-mediated spectral filtering enhances color discrimination, but that this improvement is traded off against a reduction in sensitivity that can compromise visual discrimination. Thus, retinal carotenoid levels may be optimized to meet the visual demands of specific behavioral tasks and light environments.http://europepmc.org/articles/PMC3126843?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Matthew B Toomey
Kevin J McGraw
spellingShingle Matthew B Toomey
Kevin J McGraw
The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
PLoS ONE
author_facet Matthew B Toomey
Kevin J McGraw
author_sort Matthew B Toomey
title The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
title_short The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
title_full The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
title_fullStr The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
title_full_unstemmed The effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
title_sort effects of dietary carotenoid supplementation and retinal carotenoid accumulation on vision-mediated foraging in the house finch.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2011-01-01
description BACKGROUND: For many bird species, vision is the primary sensory modality used to locate and assess food items. The health and spectral sensitivities of the avian visual system are influenced by diet-derived carotenoid pigments that accumulate in the retina. Among wild House Finches (Carpodacus mexicanus), we have found that retinal carotenoid accumulation varies significantly among individuals and is related to dietary carotenoid intake. If diet-induced changes in retinal carotenoid accumulation alter spectral sensitivity, then they have the potential to affect visually mediated foraging performance. METHODOLOGY/PRINCIPAL FINDINGS: In two experiments, we measured foraging performance of house finches with dietarily manipulated retinal carotenoid levels. We tested each bird's ability to extract visually contrasting food items from a matrix of inedible distracters under high-contrast (full) and dimmer low-contrast (red-filtered) lighting conditions. In experiment one, zeaxanthin-supplemented birds had significantly increased retinal carotenoid levels, but declined in foraging performance in the high-contrast condition relative to astaxanthin-supplemented birds that showed no change in retinal carotenoid accumulation. In experiments one and two combined, we found that retinal carotenoid concentrations predicted relative foraging performance in the low- vs. high-contrast light conditions in a curvilinear pattern. Performance was positively correlated with retinal carotenoid accumulation among birds with low to medium levels of accumulation (∼0.5-1.5 µg/retina), but declined among birds with very high levels (>2.0 µg/retina). CONCLUSION/SIGNIFICANCE: Our results suggest that carotenoid-mediated spectral filtering enhances color discrimination, but that this improvement is traded off against a reduction in sensitivity that can compromise visual discrimination. Thus, retinal carotenoid levels may be optimized to meet the visual demands of specific behavioral tasks and light environments.
url http://europepmc.org/articles/PMC3126843?pdf=render
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