Visual acuity and the eye

Beynon, J. H.

doi:10.1088/0031-9120/20/5/006

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…The mixing of these multiple color domains to produce the brilliant near angle-independent yellow-green appearance of E. chevrolati, is similar to the painting technique of pointillism [45]. In this technique, individual bright dots of different hues are placed so that the color spots blend into a fuller range of tones [46]. This new color blend arises since color patterns below the neural resolution limit are removed from the retinal image by the optical system of the human eye [47,48].…”

Section: Resultsmentioning

confidence: 99%

Photonic crystal micro-pixelation and additive color mixing in weevil scales

2018

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The origin of the brilliant near angle-independent coloration of the weevil Eupholus chevrolati was investigated by a combination of optical and electron microscopy tools, photonic band structure calculations, and color mixing analysis. Optical microscopy and scanning micro-spectroscopy revealed the presence of micrometer-sized red, yellow, green, and blue reflective pixels covering the entire exoskeleton of the weevil. Scanning electron microscopy in combination with focused ion beam milling showed that each micro-pixel consisted of a diamond-based photonic crystal structure and the different reflective colors were the result of different orientations of the photonic crystal. Color mixing analysis was used to study the collective behavior of the reflective micro-pixels. A pointillist, additive color-mixing scheme of the reflective photonic crystal micro-pixels was determined as the origin of the weevil's bright and near angle-independent yellow-green coloration.

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Section: Resultsmentioning

confidence: 99%

Photonic crystal micro-pixelation and additive color mixing in weevil scales

2018

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Visual detection of diminutive floral guides in the bumblebee Bombus terrestris and in the honeybee Apis mellifera

2009

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Many flowers display colour patterns comprising a large peripheral colour area that serves to attract flower visitors from some distance, and a small central, contrastingly coloured area made up by stamens or floral guides. In this study, we scaled down the size of floral guides to detect the minimal size bumblebees (Bombus terrestris) and honeybees (Apis mellifera) require for guidance. We analyzed the approach and the precise contact of the antennal tips with the floral guide of artificial flowers which precedes landing and inspection. Both bumblebees and honeybees were able to make antennal contact with circular floral guides which were 2 mm in diameter; bumblebees performed better than honeybees and antennated also at floral guides smaller than 2 mm. In discrimination experiments with bumblebees, a minimum floral guide size of 2 mm was required for discrimination between artificial flowers with and without floral guides. With increasing experience bumblebees targeted close to the site of reward instead of making antennal contact with the floral guide, whereas honeybees did not alter their initial behaviour with growing experience. Bumblebees and honeybees spontaneously target diminutive floral guides to achieve physical contact with flowers by means of their antennae which helps them to inspect flowers.

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