Almut Kelber

Almut Kelber
Lund University | LU · Department of Biology

Dr.rer.nat

About

179
Publications
55,125
Reads
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6,965
Citations
Introduction
Almut Kelber is a professor of Sensory Biology at the Department of Biology, Lund University. Almut does research in neuroethology and sensory ecology, and her interests are in vision, and specifically colour vision, of animals including birds, insects, mammals and many others. She is presently also Director of Research Grants at HFSPO. If you want to contact me, please send me an email and don't try to communicate via Research Gate.
Additional affiliations
September 1998 - present
Lunds Universitet
January 1997 - July 1998
Australian National University
April 1994 - December 1995
University of Tuebingen
Position
  • PostDoc Position
Education
April 1989 - March 1993
University of Tuebingen
Field of study
  • Animal Physiology, Neurophysiology
April 1985 - April 1989
University of Tuebingen
Field of study
  • Biology, Electronics, Psychology
October 1982 - April 1985
Johannes Gutenberg-Universität Mainz
Field of study
  • Biology major

Publications

Publications (179)
Article
Full-text available
Studies on animal colour vision typically focus on the chromatic aspect of colour, which is related to the spectral distribution, and disregard the achromatic aspect, which is related to the intensity (“brightness”) of a stimulus. Although the chromatic component of vision is often most reliable for object recognition because it is fairly context i...
Article
Lunar eclipses are known to influence flight activity of tropical bats at foraging sites. However, little is known about the onset and offset of flight activity from the roost during lunar eclipses compared to other full moon nights. Emergence from and return to the roost were observed during a total lunar eclipse at a colony of the fruit bat Rouse...
Article
Full-text available
Stingless bees are important pollinators in the tropics. The tremendous variation in body size makes them an excellent group to study how miniaturization affects vision and visual behaviours. Using direct measurements and micro-CT, we reconstructed the eye structure, estimated anatomical spatial resolution and optical sensitivity of the stingless b...
Article
Full-text available
Combining studies of animal visual systems with exact imaging of their visual environment can get us a step closer to understand how animals see their “Umwelt”. Here, we have combined both methods to better understand how males of the speckled wood butterfly, Pararge aegeria , see the surroundings of their perches. These males are well known to sit...
Article
Full-text available
Most vertebrates have UV-sensitive vision, but the UV-sensitivity of their eyes is limited by the transmittance of the ocular media, and the specific contribution of the different media (cornea, lens) has remained unclear. Here we describe the transmittance of all ocular media (OMT), as well as that of lenses and corneas of birds. For 66 species be...
Article
Full-text available
For a bird, it is often vital to visually detect food items, predators, or individuals from the same flock, i.e. moving stimuli of various shapes. Yet, behavioural tests of visual spatial acuity traditionally use stationary gratings as stimuli. We have behaviourally tested the ability of budgerigars (Melopsittacus undulatus) to detect a black circu...
Article
Full-text available
Fruit-feeding pteropodid bats roost under varying light conditions. Some roost in trees with high exposure to daylight (> 1000 lx), while others roost in dark caves (< 0.1 lx). To understand the effect of ambient light intensity and moon phase on flight activity, we examined flight times across five lunar cycles in three pteropodid species whose ro...
Article
Full-text available
Bees exemplify flights under bright sunlight. A few species across bee families have evolved nocturnality, displaying remarkable adaptations to overcome limitations of their daylight-suited apposition eyes. Phase inversion to nocturnality in a minority of bees that co-exist with diurnal bees provides a unique opportunity to study ecological benefit...
Article
How well can a bird discriminate between two red berries on a green background? The absolute threshold of colour discrimination is set by photoreceptor noise, but animals do not perform at this threshold; their performance can depend on additional factors. In humans and zebra finches, discrimination thresholds for colour stimuli depend on backgroun...
Article
Full-text available
Color vision is widespread among insects but varies among species, depending on the spectral sensitivities and interplay of the participating photoreceptors. The spectral sensitivity of a photoreceptor is principally determined by the absorption spectrum of the expressed visual pigment, but it can be modified by various optical and electrophysiolog...
Article
Full-text available
Cephalopods have very conspicuous eyes that are often compared to fish eyes. However, in contrast to many fish, the eyes of cephalopods possess mobile pupils. To increase the knowledge of pupillary and thus visual function in cephalopods, the dynamics of the pupil of one of the model species among cephalopods, the common octopus (Octopus vulgaris),...
Article
Full-text available
Raptors have always fascinated mankind, owls for their highly sensitive vision, and eagles for their high visual acuity. We summarize what is presently known about the eyes as well as the visual abilities of these birds, and point out knowledge gaps. We discuss visual fields, eye movements, accommodation, ocular media transmittance, spectral sensit...
Article
Full-text available
Birds, and especially raptors, are believed to forage mainly using visual cues. Indeed, raptors (scavengers and predators) have the highest visual acuity known to date. However, scavengers and predators differ in their visual systems such as in their foveal configuration. While the function of the foveal shape remains unknown, individual variation...
Article
Full-text available
Octopus vulgaris, well-known from temperate waters of the Mediterranean Sea and a well-cited model species among the cephalopods, has large eyes with which it scans its environment actively and which allow the organism to discriminate objects easily. On cursory examination, the single-chambered eyes of octopus with their spherical lenses resemble v...
Article
Full-text available
The amount of short wavelength (ultraviolet (UV), violet and blue) light that reaches the retina depends on the transmittance properties of the ocular media, especially the lens, and varies greatly across species in all vertebrate groups studied previously. We measured the lens transmittance in 32 anuran amphibians with different habits, geographic...
Article
Full-text available
Birds, and especially raptors, are highly visual animals. Some of them have the highest spatial resolving power known in the animal kingdom, allowing prey detection at distance. While many raptors visually track fast-moving and manoeuvrable prey, requiring high temporal resolution, this aspect of their visual system has never been studied before. I...
Article
Birds use spectral information for circadian control, magnetic orientation and phototaxis but most importantly for discriminating the colours of important objects such as food items or mates. Their tetrachromatic colour vision is based on four types of single cones expressing four opsin-based visual pigments and fine-tuned by the carotenoid composi...
Article
Full-text available
The family Apidae, which is amongst the largest bee families, are important pollinators globally and have been well studied for their visual adaptations and visually guided behaviors. This review is a synthesis of what is known about their eyes and visual capabilities. There are many species-specific differences, however, the relationship between b...
Article
The colours of insects serve important visual functions in aiding mate recognition, camouflage and warning. The display of insects is usually static, as cuticle coloration does not (or hardly) change during the lifespan of a mature imago form. Here, we describe a case of humidity-dependent, brilliant coloration in the green forester moth, Adscita s...
Preprint
Full-text available
The amount of short wavelength (UV, violet and blue) light that reaches the retina depends on the transmittance properties of the ocular media, especially the lens, and varies greatly across species in all vertebrate groups studied previously. We measured the lens transmittance in 32 anuran amphibians with different habits, geographic distributions...
Article
Full-text available
The Moon cycle exposes nocturnal life to variation in environmental light. However, whether moonlight shapes the fitness of nocturnal species with distinct colour variants remains unknown. Combining data from long-term monitoring, high-resolution global positioning system tracking and experiments using prey, we show that barn owls (Tyto alba) with...
Data
Links to files containing ocular media transmittance and spectral sensitivities datasets
Article
We examined the capacity of budgerigars (Melopsittacus undulatus) to visually detect dark single targets against a brighter background and established their spatial resolution limit for such targets. While the sampling density of the retina limits the resolution of gratings, target detection is theoretically limited by contrast sensitivity. This al...
Article
Full-text available
The transmittance properties of the cornea, lens and humours of vertebrates determine how much light across the visible spectrum reaches the retina, influencing sensitivity to visual stimuli. Amphibians are the only vertebrate class in which the light transmittance of these ocular media have not been thoroughly characterised, preventing large-scale...
Article
Full-text available
Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and o...
Article
Pit vipers detect moving warm-blooded prey with infrared receptors in their pit organs. Neurons in two brain nuclei extract the direction of prey motion by lateral inhibition circuits similar to those known from visual systems.
Article
Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensit...
Article
Animal colours commonly act as signals for mates or predators. In many damselfly species, both sexes go through a developmental colour change as adults, and females often show colour polymorphism, which may have a function in mate choice, avoidance of mating harassment and camouflage. In the blue-tailed damselfly, Ischnura elegans, young males are...
Article
Full-text available
Solitary insects that feed on floral nectar must use innate knowledge to find their first flower. While innate preferences for flower colours are often described as fixed, species-specific traits, the nature and persistence of these preferences have been debated, particularly in relation to ontogenetic processes such as learning. Here we present ev...
Article
Full-text available
Flying animals need continual sensory feedback about their body position and orientation for flight control. The visual system provides essential but slow feedback. In contrast, mechanosensory channels can provide feedback at much shorter timescales. How the contributions from these two senses are integrated remains an open question in most insect...
Article
Full-text available
Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the...
Article
Visually-guided behaviour is constrained by the capacity of the visual system to resolve detail. This is, in turn, limited by the spatial resolution and contrast sensitivity of the underlying visual system. Because these properties are interdependent and vary non-uniformly, it is only possible to fully understand the limits of a specific visually g...
Article
Humans perceive colours in categories such as red, even though we can discern red hues including ruby and crimson. It emerges that birds also categorize colours and this affects their colour-discrimination ability. Humans perceive colours in categories such as red, even though we can discern red hues including ruby and crimson. It emerges that bird...
Preprint
Flying animals need constant sensory feedback about their body position and orientation for flight control. The visual system provides essential but slow feedback. In contrast, mechanosensory channels can provide feedback at much shorter timescales. How the contributions from these two senses are integrated remains an open question in most insect g...
Article
Rods, usually associated with highly sensitive dim-light vision, contribute to vision even in bright photopic intensities. New results in mice have important implications for vision of animals with rod-dominated or pure rod retinae.
Chapter
Full-text available
Diurnal raptors (birds of the orders Accipitriformes and Falconiformes), renowned for their extraordinarily sharp eyesight, have fascinated humans for centuries. The high visual acuity in some raptor species is possible due to their large eyes, both in relative and absolute terms, and a high density of cone photoreceptors. Some large raptors, such...
Article
Full-text available
Although predation is commonly thought to exert the strongest selective pressure on colouration in aposematic species, sexual selection may also influence colouration. Specifically, polymorphism in aposematic species cannot be explained by natural selection alone. 2.Males of the aposematic wood tiger moth (Arctia plantaginis) are polymorphic for hi...
Article
Little is known about the development of vision in wild birds. It is unknown, for example, whether the ability to see can be predicted by the level of prenatal growth or whether the eyes are open at hatching in a particular species. In this study, we investigated the growth of eyes, the formation of retinal ganglion cell topography, and the appeara...
Article
Full-text available
Many insects rely on vision to find food, to return to their nest and to carefully control their flight between these two locations. The amount of information available to support these tasks is, in part, dictated by the spatial resolution and contrast sensitivity of their visual systems. Here, we investigate the absolute limits of these visual pro...
Article
Many animals use vision to detect, discriminate, or recognize important objects such as prey, predators, homes, or mates. These objects may differ in color and brightness—having chromatic and achromatic contrast to the background or to other objects. Visual models are powerful tools to investigate contrast detection, but need to be calibrated by ex...
Article
Birds with larger eyes are predicted to have higher spatial resolution because of their larger retinal image. Raptors are well known for their acute vision, mediated by their deep central fovea. Because foraging strategies may demand specific visual adaptations, eye size and fovea may differ between species with different foraging ecology. We teste...
Article
Full-text available
Many insects rely on vision to find food, to return to their nest and to carefully control their flight between these two locations. The amount of information available to support these tasks is, in part, dictated by the spatial resolution and contrast sensitivity of their visual systems. Here, we investigate the absolute limits of these visual pro...
Article
Full-text available
Coloration mediates the relationship between an organism and its environment in important ways, including social signaling, antipredator defenses, parasitic exploitation, thermoregulation, and protection from ultraviolet light, microbes, and abrasion. Methodological breakthroughs are accelerating knowledge of the processes underlying both the produ...
Article
Full-text available
The evolutionary relationship between signals and animal senses has broad significance, with potential consequences for speciation, and for the efficacy and honesty of biological communication. Here we outline current understanding of the diversity of colour vision in two contrasting groups: the phylogenetically conservative birds, and the more var...
Article
Full-text available
Background: The colors in which we see an object are not only dependent on the spectral composition of the reflected light but also represent an interpretation by our eyes and the trichromatic visual system. Objective: How do animals of other species see the world? Results: The majority of mammals do not have three but only two types of cones...
Article
Full-text available
The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the th...
Article
Full-text available
Colour discrimination is based on opponent photoreceptor interactions, and limited by receptor noise. In dim light, photon shot noise impairs colour vision, and in vertebrates, the absolute threshold of colour vision is set by dark noise in cones. Nocturnal insects (e.g. moths and nocturnal bees) and vertebrates lacking rods (geckos) have adaptatio...
Data
http://rstb.royalsocietypublishing.org/content/royptb/suppl/2017/02/03/rstb.2016.0066.DC1/rstb20160066supp1.pdf
Article
Full-text available
A ripe strawberry looks red to our eyes in sunlight and in the green light of a forest, although the spectrum of light reflected from its surface differs dramatically. This is caused by two effects, colour constancy, and our ability to learn relative colour cues: the ripe strawberry remains relatively "redder" than an unripe green strawberry. While...
Article
Full-text available
The retinae of many bird species contain a depression with high photoreceptor density known as the fovea. Many species of raptors have two foveae, a deep central fovea and a shallower temporal fovea. Birds have six types of photoreceptors: rods, active in dim light, double cones that are thought to mediate achromatic discrimination, and four types...
Article
Full-text available
Sexual dimorphism in eye structure is attributed to sexual selection in animals that employ vision for locating mates. In many male insects, large eyes and eye regions of higher acuity are believed to facilitate the location of females. Here, we compare various features of male and female eyes in three sympatric carpenter bee species, which include...
Data
Field experiments estimating the reaction of perching male X. tenuiscapa to stones thrown of known sizes. (XLSX)
Data
Mate location behaviour and associated morphological adaptations reported in male carpenter bees. (DOCX)
Article
Full-text available
While color vision and spatial resolution have been studied in many bird species, less is known about the temporal aspects of bird vision. High temporal resolution has been described in three species of passerines but it is unknown whether this is specific to passerines, to small actively flying birds, to insectivores or to birds living in bright h...
Article
Colour vision — the ability to discriminate spectral differences irrespective of variations in intensity — has two basic requirements: (1) photoreceptors with different spectral sensitivities, and (2) neural comparison of signals from these photoreceptors. Major progress has been made understanding the evolution of the basic stages of colour vision...
Article
Full-text available
Night,dawn,and dusk have abiotic features that differ from the day. Illumination,wind speeds,turbulence,and temperatures are lower while humidity may be higher at night. Nocturnal pollination occurred in 30% of angiosperm families across 68% of orders,97% of families with C3,two-thirds of fam-ilies with crassulacean acid metabolism (CAM),and 71% di...
Chapter
Abstract: Research conducted in recent years has documented the widespread presence of various forms of color vision in species from across the animal kingdom, helped to develop an understanding of the basic biological mechanisms that underlie this sensory capacity, and provided some insights into the utility of color vision in the natural world. T...
Article
Full-text available
Color guides many important behaviors in birds. Previously we have shown that the intensity threshold for color discrimination in the chicken depends on the color contrast between stimuli and their brightness. The birds could discriminate larger color contrasts and brighter colors in lower light intensities. We suggested that chickens use spatial s...
Article
Butterfly eyes are random mosaics built of three ommatidia types, each with a different set of photoreceptors and pigments. What defines the combined features in each ommatidium? A new study has solved the puzzle.
Article
Full-text available
Procellariiform or 'tubenosed' seabirds are challenged to find prey and orient over the seemingly featureless oceans. Previous studies have found that life history strategy (burrow vs. surface nesting) was correlated to foraging strategy. Burrow nesters tended to track prey using dimethyl sulphide (DMS), a compound associated with phytoplankton, wh...
Data
The PCR primers used in studies of enzyme function and expression. (a) PCR primers used to clone in situ hybridization templates. (b) Primers used for qPCR quantification of apocarotenoid-metabolizing enzyme transcript expression in developing chicken retinas. (c) PCR primers used to clone full-length transcripts of apocarotenoid-metabolizing enzym...
Data
The number of discriminable colors predicted using the receptor noise-limited model with species-specific ocular media transmittance, spectral sensitivity measures, and varying positions of the C-type oil droplet filtering cutoff.The increment spectral sensitivity values calculated for the 11 UVS and 7 VS species with matched and mismatched C-type...
Data
The species included in our phylogenetic comparison of retina apocarotenoid composition. The tuning of the SWS1 opsin is inferred from the amino acid at position 90 of the second transmembrane helix (Ödeen and Håstad, 2013; 2009). The amino acid sequence was either derived from previously published studies or was determined by sequencing of genomic...