Avian Ultraviolet Vision And Frequency-Dependent Seed Preferences
It is well established that ultraviolet sensitivity plays an important role in the visually guided behaviour of birds. From a foraging perspective, evidence now exists that ultraviolet wavelengths are used by birds when foraging for insects, berries, seeds and mammals. Here, we present the results of two laboratory experiments that test the effect of removing […]
Is the ultraviolet waveband a special communication channel in avian mate choice?
There is growing evidence that ultraviolet (UV) wavelengths play an important role in avian mate choice. One of the first experiments to support this idea showed that female zebra finches (Taeniopygia guttata) prefer UV-reflecting males to males whose ultraviolet reflection has been removed. The effect was very strong despite little or no UV reflection from […]
Sensory Ecology of Feeding in the Hummingbird Hawkmoth Macroglossum stellatarum (Lepidoptera: Sphingidae)
The European hummingbird hawkmoth, Macroglossum stellatarum (Linnaeus 1758), drinks nectar while hovering in front of flowers of all colours, odours, sizes and shapes. Naive moths orient predominantly towards visual stimuli and prefer blue flowers with a radial pattern and a central contrasting spot. Hummingbird hawkmoths have trichromatic colour vision and can learn any colour and […]
Photoreceptor sectral sensitivities in terrestrial animals: adaptations for luminance and colour vision
This review outlines how eyes of terrestrial vertebrates and insects meet the competing requirements of coding both spatial and spectral information. There is no unique solution to this problem. Thus, mammals and honeybees use their long-wavelength receptors for both achromatic (luminance) and colour vision, whereas flies and birds probably use separate sets of photoreceptors for […]
The Intra-Ocular Colour Filters of Vertebrates
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Behavioural evidence of dichromacy in a species of South American marsupial
Colour vision in marsupials is a controversial issue, especially among the genus Didelphis (Didelphidae, Didelphimorphia). While behavioural tests have diagnosed these animals as trichromats and electrophysiological studies have diagnosed them as monochromats, recent molecular genetics studies provide evidence for dichromatic colour vision, having found two classes of cone opsins in a species of this genus. […]
Changes in the visual environment affect colour signal brightness and shoaling behaviour in a freshwater fish
Aquatic organisms are exposed to highly variable light environments, which can affect the efficacy of colour patterns that are used for communication or camouflage. Specifically, dissolved organic matter that is common in turbid freshwater habitats tends to absorb short wavelength light causing a shift towards environments that are rich in longwavelengths (orange/red).We investigatedhowchanges in the […]
The Ecology of Color Vision
Colour vision in man is well understood, but for obvious experimental reasons it is less so in the case of other animals. Some evidentally have a three-colour system similar to our own but based on different primary colours. In particular, some are sensitive to ultraviolet light, which the human eye is not.
Why Aye-Ayes See Blue
The capacity for cone-mediated color vision varies among nocturnal primates. Some species are colorblind, having lost the functionality of their short-wavelength-sensitive-1 (SWS1) opsin pigment gene. In other species, such as the aye-aye (Daubentonia madagascariensis), the SWS1 gene remains intact. Recent studies focused on aye-ayes indicate that this gene has been maintained by natural selection and […]
An investigation of colour discrimination with horses (Equus caballus)
The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in […]