A cute and highly contrast-sensitive superposition eye - the diurnal owlfly Libelloides macaronius (original) (raw)
Related papers
Mechanism for Visual Detection of Small Targets in Insects
2013
* although not listed as a PI on the original proposal, Dr Wiederman was supported exclusively from the funding provided and contributed to all aspects of the project, including conception of experiments, collection and analysis of data, computational modeling and writing of papers arising from the research, as well as to this report.
Surprising characteristics of visual systems of invertebrates
Archivos De La Sociedad Española De Oftalmología (english Edition), 2017
Objective: To communicate relevant and striking aspects about the visual system of some close invertebrates. Material and methods: Review of the related literature. Results: The capacity of snails to regenerate a complete eye, the benefit of the oval shape of the compound eye of many flying insects as a way of stabilizing the image during flight, the potential advantages related to the extreme refractive error that characterizes the ocelli of many insects, as well as the ability to detect polarized light as a navigation system, are some of the surprising capabilities present in the small invertebrate eyes that are described in this work. Conclusions: The invertebrate eyes have capabilities and sensorial modalities that are not present in the human eye. The study of the eyes of these animals can help us to improve our understanding of our visual system, and inspire the development of optical devices.
Target detection in insects: optical, neural and behavioral optimizations
Current opinion in neurobiology, 2016
Motion vision provides important cues for many tasks. Flying insects, for example, may pursue small, fast moving targets for mating or feeding purposes, even when these are detected against self-generated optic flow. Since insects are small, with size-constrained eyes and brains, they have evolved to optimize their optical, neural and behavioral target visualization solutions. Indeed, even if evolutionarily distant insects display different pursuit strategies, target neuron physiology is strikingly similar. Furthermore, the coarse spatial resolution of the insect compound eye might actually be beneficial when it comes to detection of moving targets. In conclusion, tiny insects show higher than expected performance in target visualization tasks.
Sampling of the Visual Environment by the Compound Eye of the Fly: Fundamentals and Applications
Photoreceptor Optics (A. Snyder and R. Menzel, eds.) Springer, Berlin, Germany, 1975
This paper reviews some experiments which have been done to elucidate how a fly looks at its surroundings. Stimulation for such a study arose out of the conviction that the neural processing of information in the compound eye might better be unravelled with a precise stimulation of single receptor cells and that such a fine stimulation requires a better understanding of the optics. First a method for visualizing the distal receptor endings in the retina of a live and intact fly is presented. Then follows an analysis of the optical properties of the single ommatidium and neuroommatidium, and finally it is shown how the whole eye samples its visual environment. By looking at the compound eye through a telescope one gets a direct insight into its visual sampling raster which apparently is much more regular than the facet raster and shows a gradual increase in resolution from the back to the front part of the eye. In Chapter 8 the principle of formation of the deep pseudopupil (DPP) is explained and illustrated for Drosophila and also for two insects having fused rhabdoms. Chapter 9 briefly reviews some results related to the rapid mechanïsm of light regulation in the rhabdomeres. As a consequence of this optical study, one can now propose several methods for selectively stimulating single and well identified photoreceptor cells or neuroommatidia in the living and intact animal. All of these methods can be combined with electrophysiological or behavioural experiments. It will be shown in the conclusion how a pattern (static or moving) can be presented so as to be seen only by one of the fly's two visual systems.
Stark trade-offs and elegant solutions in arthropod visual systems
Journal of Experimental Biology
Vision is one of the most important senses for humans and animals alike. Diverse elegant specializations have evolved among insects and other arthropods in response to specific visual challenges and ecological needs. These specializations are the subject of this Review, and they are best understood in light of the physical limitations of vision. For example, to achieve high spatial resolution, fine sampling in different directions is necessary, as demonstrated by the well-studied large eyes of dragonflies. However, it has recently been shown that a comparatively tiny robber fly (Holcocephala) has similarly high visual resolution in the frontal visual field, despite their eyes being a fraction of the size of those of dragonflies. Other visual specializations in arthropods include the ability to discern colors, which relies on parallel inputs that are tuned to spectral content. Color vision is important for detection of objects such as mates, flowers and oviposition sites, and is part...
Proceedings of the National Academy of Sciences of the United States of America, 2011
The compound eye of insects imposes a tradeoff between resolution and sensitivity, which should exacerbate with diminishing eye size. Tiny lenses are thought to deliver poor acuity because of diffraction; nevertheless, miniature insects have visual systems that allow a myriad of lifestyles. Here, we investigate whether size constraints result in an archetypal eye design shared between miniature dipterans by comparing the visual performance of the fruit fly Drosophila and the killer fly Coenosia. These closely related species have neural superposition eyes and similar body lengths (3 to 4 mm), but Coenosia is a diurnal aerial predator, whereas slow-flying Drosophila is most active at dawn and dusk. Using in vivo intracellular recordings and EM, we report unique adaptations in the form and function of their photoreceptors that are reflective of their distinct lifestyles. We find that although these species have similar lenses and optical properties, Coenosia photoreceptors have three-to fourfold higher spatial resolution and rate of information transfer than Drosophila. The higher performance in Coenosia mostly results from dramatically diminished light sensors, or rhabdomeres, which reduce pixel size and optical cross-talk between photoreceptors and incorporate accelerated phototransduction reactions. Furthermore, we identify local specializations in the Coenosia eye, consistent with an acute zone and its predatory lifestyle. These results demonstrate how the flexible architecture of miniature compound eyes can evolve to match information processing with ecological demands. vision | predatory behavior | invertebrate | evolution T he design of a compound eye depends on the limits imposed by body size, architectural properties of the eye, visual task, and habitat, all of which affect its ability to resolve environmental light patterns (1-3). Typically, compound eyes are roughly spherical in shape, sectored into arrays of lens-capped sampling units, named ommatidia, which accept light from narrow angles (3), determining their sampling resolution (4). Although the eye's sampling resolution can improve when its lenses shrink, their projected image blurs more because of diffraction (5). The optimal lens diameter, which is expected when these two limits nearly meet, scales with the square root of the eye size across many insect species (5), implying high resolution as their design objective. However, smaller lenses collect less light, reducing the signal-tonoise ratio (SNR) of the sampled image (4). Although the lenses perform light collection, the focal length of the lens and the diameter of the light guides, or rhabdomeres, finally determine the pixel size (6). In combination, lens diameter, rhabdomere width, and focal length impose a tradeoff between spatial resolution and sensitivity (intensity resolution), which is thought to be further aggravated the smaller the eyes .
Biomimetic visual detection based on insect neurobiology
With a visual system that accounts for as much as 30% of the lifted mass, flying insects such as dragonflies and hoverflies invest more in vision than any other animal. Impressive visual performance is subserved by a surprisingly simple visual system. In a typical insect eye, between 2,000 and 30,000 pixels in the image are analyzed by fewer than 200,000 neurons in underlying neural circuits. The combination of sophisticated visual processing with an approachable level of complexity has made the insect visual system a leading model for biomimetic approaches to computer vision. Much neurobiological research has focused on neural circuits used for detection of moving patterns (e.g. optical flow during flight) and moving targets (e.g. prey). Research from several labs has led to great advances in our understanding of the neural mechanisms involved, and has spawned neuromorphic hardware based on key processes identified in neurobiological experiments. Despite its attractions, the highly non-linear nature of several key stages in insect visual processing presents a challenge to understanding. I will describe examples of adaptive elements of neural circuits in the fly visual system which analyze the direction and velocity of wide-field optical flow patterns and the result of experiments that suggest that these non-linearities may contribute to robust responses to 'natural' image motion.
2003
the optical quality of the eye (Exner, 1891; Burtt and Catton, 1962; Kirschfeld, 1984; Land, 1999; Warrant and McIntyre, 1993) as well as intrinsic properties of the target such as size, shape and colour (Srinivasan and Lehrer, 1988; Giurfa et al., 1996; Lehrer and Bischof, 1995; Dafni et al., 1997; Ne’eman and Kevan, 2001; Spaethe et al., 2001). Eye optics are limited by eye size, which in turn is constrained by body size (Kirschfeld, 1976; Nilsson, 1990; Rutowski, 2000; Wehner, 1981). However, eye optics only set the upper limit to visual resolution; they do not determine it directly. This is because there can be significant convergence in the neuronal processing of signals from the visual periphery. In honeybees ( Apis mellifera), for example, the resolving power of the ommatidial array is about 1° (Hecht and Wolf, 1929; Dafni and Kevan, 1995; Land, 1999). However, behavioural experiments reveal that in single object detection tasks, such as perceiving a coloured flower against i...
Localization of the pupil trigger in insect superposition eyes
Journal of Comparative Physiology A, 1992
In the superposition eyes of the sphingid moth Deilephila and the neuropteran Ascalaphus, adjustment to different intensities is subserved by longitudinal migrations of screening pigment in specialized pigment cells. Using ophthalmoscopic techniques we have localized the light-sensitive trigger that controls pigment position. In both species, local illumination of a small spot anywhere within the eye glow of a dark-adapted eye evokes local light adaptation in the ommatidia whose facets receive the light. Details of the response pattern demonstrate that a distal light-sensitive trigger is located axially in the ommatidium, just beneath the crystalline cone, and extends with less sensitivity deep into the clear zone. The distal trigger in Deilephila was shown to be predominantly UV sensitive, and a UV-absorbing structure, presumably the distal trigger, was observed near the proximal tip of the crystalline cone. In Ascalaphus we also found another trigger located more proximally, which causes local pigment reaction in the ommatidia whose rhabdoms are illuminated (the centre of the eye glow). The light-sensitive trigger for this response appears to be the rhabdom itself.
2008
: Habitats characterized by high spatial variation in absolute light levels and spectral quality present a challenge to animals that rely on visual orientation and visual target discrimination. Insects, in particular, face several difficulties in visual performance related to the small absolute size and simplicity of visual components comprising their compound eyes, including the lack of a focusing mechanism, relatively limited light capture and course spatial resolution. Therefore, an understanding of the morphological and behavioral means by which insects overcome these limitations in order to perform highly demanding visual tasks can provide insight into both ecological specialization and artificial visual system optimization. We investigated optical geometry, perch orientation and microhabitat selection in the Hawaiian damselfly Megalagrion xanthomelas, a sit-and-wait predator that intercepts aerial prey among heterogeneous vegetation bordering streams and wetlands. We found tha...