Ultraviolet vision in Ord’s kangaroo rat (Dipodomys ordii)

Abstract Knowledge of a species’ visual system has far reaching implications that affect our understanding of a species’ ecology and evolutionary history. As a model taxon, the heteromyid rodent genus Dipodomys has been valuable in elucidating patterns and mechanisms in biomechanics, ecology, adaptive physiology, biogeography, and more. Although studied extensively, the visual system of Dipodomys has not been described beyond anecdotal mention of their large eyes. Here, the transmittance parameters of the cornea and lens of Ord’s kangaroo rat (Dipodomys ordii) were analyzed and photoreceptor proteins (opsins) expressed in the retina were identified with immunohistochemical (IHC) labeling. Retina maps were constructed to illustrate the relative densities of photoreceptor cells expressing short wavelength (SWS1) opsins, middle/long wavelength (MW/LW) opsins, and rhodopsin (RH1). The retina of D. ordii has variable densities of SWS1 opsin with the highest density being ventral to the optic nerve, high density of MW/LW opsin, and uniform distribution and high density of RH1 across the retina. Our results suggest that D. ordii has a UV-sensitive visual system. Composition and densities of MW/LW- and SWS1-expressing cells resemble that of a crepuscular/diurnal species thereby supporting previous authors who have reported such activity patterns. Uniform retinal distribution of RH1 indicates visual acuity at night, also confirming the paradigm of D. ordii as primarily a nocturnal species and suggesting visual acuity at all times of the day in the species. These results demonstrate not only that the species is capable of UV vision and has a retina characteristic of a diurnal mammal, but that many previously unknown photic niche selective advantages likely have shaped the evolution and ecology of this model taxon.

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Eye shape and the nocturnal bottleneck of mammals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.2258 ◽

2012 ◽

Vol 279 (1749) ◽

pp. 4962-4968 ◽

Cited By ~ 64

Author(s):

Margaret I. Hall ◽

Jason M. Kamilar ◽

E. Christopher Kirk

Keyword(s):

Visual Acuity ◽

Detailed Analysis ◽

Statistical Methods ◽

Activity Pattern ◽

Activity Patterns ◽

Time Of Day ◽

Visual Sensitivity ◽

Early Evolution ◽

Eye Size ◽

Diurnal Species

Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal ‘bottleneck’ in the early evolution of crown mammals.

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Transformation from independent to integrative coding of multi-object arrangements in human visual cortex

10.1101/117432 ◽

2017 ◽

Cited By ~ 1

Author(s):

Daniel Kaiser ◽

Marius V. Peelen

Keyword(s):

Visual Cortex ◽

Visual System ◽

Activity Patterns ◽

Spatial Arrangement ◽

Living Room ◽

Natural Scenes ◽

Response Patterns ◽

Object Representations ◽

Individual Object ◽

Object Coding

AbstractTo optimize processing, the human visual system utilizes regularities present in naturalistic visual input. One of these regularities is the relative position of objects in a scene (e.g., a sofa in front of a television), with behavioral research showing that regularly positioned objects are easier to perceive and to remember. Here we use fMRI to test how positional regularities are encoded in the visual system. Participants viewed pairs of objects that formed minimalistic two-object scenes (e.g., a “living room” consisting of a sofa and television) presented in their regularly experienced spatial arrangement or in an irregular arrangement (with interchanged positions). Additionally, single objects were presented centrally and in isolation. Multi-voxel activity patterns evoked by the object pairs were modeled as the average of the response patterns evoked by the two single objects forming the pair. In two experiments, this approximation in object-selective cortex was significantly less accurate for the regularly than the irregularly positioned pairs, indicating integration of individual object representations. More detailed analysis revealed a transition from independent to integrative coding along the posterior-anterior axis of the visual cortex, with the independent component (but not the integrative component) being almost perfectly predicted by object selectivity across the visual hierarchy. These results reveal a transitional stage between individual object and multi-object coding in visual cortex, providing a possible neural correlate of efficient processing of regularly positioned objects in natural scenes.

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Utilization of Visual Acuity Retroilluminated Charts for the Assessment of Afferent Visual System Dysfunction in a Pediatric Neuroimmunology Population

Journal of Neuro-Ophthalmology ◽

10.1097/wno.0000000000001001 ◽

2020 ◽

Vol Publish Ahead of Print ◽

Author(s):

Peter V. Sguigna ◽

Morgan C. McCreary ◽

Darrel L. Conger ◽

Jennifer S. Graves ◽

Leslie A. Benson ◽

...

Keyword(s):

Visual Acuity ◽

Visual System ◽

Afferent Visual System

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Visual Acuity Affected by Size Perception Based on Convergence Cue

Perception ◽

10.1068/v970198 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 354-354

Author(s):

H Shinoda ◽

M Ikeda

Keyword(s):

Visual Acuity ◽

Visual System ◽

Retinal Image ◽

White Paper ◽

Retinal Size ◽

Size Perception ◽

Convergence Angle ◽

Threshold Size

Increasing (or decreasing) the convergence angle can shrink (or expand) the perceived size of an object without changing its retinal size (Oyama, 1974 Perception & Psychophysics16 175 – 182). Here we address the question whether such a change in perceived size affects visual acuity. We investigated the effects of perceived size on the legibility of letters, using a telestereoscope consisting of four mirrors to control the observer's convergence angle while keeping the size of the retinal image constant. The targets were photocopies of ordinary Japanese books containing both types of Japanese characters, kana and kanji. The former is a phonetic character and simpler than the latter. Letters were printed in black on white paper. First, we demonstrated that letters do become more legible (illegible) as perceived size expands (shrinks), although their retinal size does not change. Then, we measured the size of the convergence angle at which letters became legible. The ‘threshold’ size of the convergence angle was obtained for several retinal sizes (0.1 to 0.2 deg) of letters, and for kana and kanji, respectively. Four subjects participated in the experiment. The result shows that the threshold convergence angle for legibility decreases as the retinal size of letters decreases, so that the minimum retinal size of legible letters depends linearly on the convergence angle. The results implicate contributions from higher levels of the visual system to the determination of visual acuity.

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The complete mitochondrial genome of the Dipodomys ordii (Ord's kangaroo rat)

Mitochondrial DNA Part A ◽

10.3109/19401736.2015.1089483 ◽

2015 ◽

Vol 27 (6) ◽

pp. 4322-4323

Author(s):

Dayang Chen ◽

Kai Zhang ◽

Sheng Liu ◽

Fang Chen

Keyword(s):

Mitochondrial Genome ◽

Complete Mitochondrial Genome ◽

Dipodomys Ordii ◽

Kangaroo Rat

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The Effect of Activity on Body Temperature of Ord's Kangaroo Rat (Dipodomys ordii)

Physiological Zoology ◽

10.1086/physzool.47.1.30155620 ◽

1974 ◽

Vol 47 (1) ◽

pp. 29-36 ◽

Cited By ~ 4

Author(s):

Bruce A. Wunder

Keyword(s):

Body Temperature ◽

Dipodomys Ordii ◽

Kangaroo Rat

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Foraging ecology of the night-active bull ant Myrmecia pyriformis

Australian Journal of Zoology ◽

10.1071/zo13027 ◽

2013 ◽

Vol 61 (2) ◽

pp. 170 ◽

Cited By ~ 12

Author(s):

Samuel F. Reid ◽

Ajay Narendra ◽

Robert W. Taylor ◽

Jochen Zeil

Keyword(s):

Visual System ◽

Foraging Ecology ◽

Activity Patterns ◽

Colony Founding ◽

Liquid Food ◽

Mating Season ◽

Wild Populations ◽

Ecological Information ◽

Light Levels ◽

Nest Activity

Here we report on the nocturnal bull ant Myrmecia pyriformis, a species whose activity to and from the nest is mainly restricted to the dawn and dusk twilight respectively. Recent research on M. pyriformis has focussed on its visual system, the timing of activity patterns, and the navigational strategies employed by individuals while foraging. There is, however, a lack of basic ecological information about this species. The present study describes the behaviour and foraging ecology of wild populations of M. pyriformis. We find that most foragers make only one foraging journey per night, leaving the nest at dusk twilight and returning during dawn twilight. Individuals who make multiple trips typically return with prey. We provide evidence that foragers imbibe liquid food while abroad and likely share these resources via trophallaxis once within the nest. Activity during the night varies with moon illumination, and we postulate that this is due to changes in light levels, which influence navigation to and from the nest. This hypothesis is supported by observations of activity during overcast conditions. Finally, we also describe some aspects of colony founding, colony demise and the behaviour of reproductive individuals during the mating season.

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