Heritage and the Visual Ecology of the Plantationocene

The encoding of light increments and decrements by separate On- and Off- systems is a fundamental ingredient of vision, which supports the detection of edges in space and time and makes efficient use of limited dynamic range of visual neurons [1]. Theory predicts that the neural representation of On- and Off-signals should be approximately balanced, including across an animals’ full visible spectrum. Here we find that larval zebrafish violate this textbook expectation: in the fish brain, UV-stimulation near exclusively gives On-responses, blue/green-stimulation mostly Off- responses, and red-light alone elicits approximately balanced On- and Off-responses (see also [2–4]). We link these findings to zebrafish visual ecology, and suggest that the observed spectral tuning boosts the encoding of object “colourfulness”, which correlates with object proximity in their underwater world [5].

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Structural colours reflect individual quality: a meta-analysis

Biology Letters ◽

10.1098/rsbl.2020.0001 ◽

2020 ◽

Vol 16 (4) ◽

pp. 20200001

Author(s):

Thomas E. White

Keyword(s):

Immune Function ◽

Body Condition ◽

Meta Analysis ◽

Visual Ecology ◽

Individual Quality ◽

Sexual Signals ◽

Parasite Resistance ◽

Structural Coloration ◽

Exchange Of Information ◽

The Relationship

Colourful ornaments often communicate salient information to mates, and theory predicts covariance between signal expression and individual quality. This has borne out among pigment-based signals, but the potential for ‘honesty’ in structural coloration is unresolved. Here, I synthesized the available evidence to test this prediction via meta-analysis and found that, overall, the expression of structurally coloured sexual signals is positively associated with individual quality. The effects varied by the measure of quality, however, with body condition and immune function reliably encoded across taxa, but not age nor parasite resistance. The relationship was apparent for both the colour and brightness of signals and was slightly stronger for iridescent ornaments. These results suggest diverse pathways to the encoding and exchange of information among structural colours while highlighting outstanding questions as to the development, visual ecology and evolution of this striking adornment.

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Beyond Visual Culture: The Challenge of Visual Ecology

portal Libraries and the Academy ◽

10.1353/pla.2002.0038 ◽

2002 ◽

Vol 2 (2) ◽

pp. 189-206 ◽

Cited By ~ 18

Author(s):

James W. Marcum

Keyword(s):

Visual Culture ◽

Visual Ecology

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Visual Ecology, by Thomas W. Cronin, Sönke Johnson, N. Justin Marshall & Eric J. Warrant. Princeton and Oxford: Princeton University Press 2014, 405pp Hardcover. ISBN 978-0-691-15184-7, £48.95.

Zoological Journal of the Linnean Society ◽

10.1111/zoj.12327 ◽

2016 ◽

Vol 176 (2) ◽

pp. 478-478

Author(s):

Pat Morris

Keyword(s):

Visual Ecology ◽

Princeton University

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Visual ecology and potassium conductances of insect photoreceptors

Journal of Neurophysiology ◽

10.1152/jn.00795.2015 ◽

2016 ◽

Vol 115 (4) ◽

pp. 2147-2157 ◽

Cited By ~ 10

Author(s):

Roman Frolov ◽

Esa-Ville Immonen ◽

Matti Weckström

Keyword(s):

Membrane Conductance ◽

Visual Ecology ◽

Calliphora Vicina ◽

Visually Guided ◽

Negative Effects ◽

Voltage Range ◽

Kv Channels ◽

Flying Insects ◽

Potassium Conductances ◽

And Behavior

Voltage-activated potassium channels (Kv channels) in the microvillar photoreceptors of arthropods are responsible for repolarization and regulation of photoreceptor signaling bandwidth. On the basis of analyzing Kv channels in dipteran flies, it was suggested that diurnal, rapidly flying insects predominantly express sustained K+ conductances, whereas crepuscular and nocturnally active animals exhibit strongly inactivating Kv conductances. The latter was suggested to function for minimizing cellular energy consumption. In this study we further explore the evolutionary adaptations of the photoreceptor channelome to visual ecology and behavior by comparing K+ conductances in 15 phylogenetically diverse insects, using patch-clamp recordings from dissociated ommatidia. We show that rapid diurnal flyers such as the blowfly ( Calliphora vicina) and the honeybee ( Apis mellifera) express relatively large noninactivating Kv conductances, conforming to the earlier hypothesis in Diptera. Nocturnal and/or slow-moving species do not in general exhibit stronger Kv conductance inactivation in the physiological membrane voltage range, but the photoreceptors in species that are known to rely more on vision behaviorally had higher densities of sustained Kv conductances than photoreceptors of less visually guided species. No statistically significant trends related to visual performance could be identified for the rapidly inactivating Kv conductances. Counterintuitively, strong negative correlations were observed between photoreceptor capacitance and specific membrane conductance for both sustained and inactivating fractions of Kv conductance, suggesting insignificant evolutionary pressure to offset negative effects of high capacitance on membrane filtering with increased conductance.

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