Vision in dim light: highlights and challenges

Vision in dim light: highlights and challenges.

On amoonless night or in the depths of the sea, where light levels aremany orders of magnitude dimmer than sunlight, animals rely on their visual systems to orient andnavigate, to find foodandmates and toavoidpredators. To seewell at such low light levels is far from trivial. The paucity of light means that visual signals generated in the light-sensitive photoreceptors of the retina can easily ...

Evolution of dim-light and color vision pigments.

A striking level of diversity of visual systems in different species reflects their adaptive responses to various light environments. To study the adaptive evolution of visual systems, we need to understand how visual pigments, the light-sensitive molecules, have tuned their wavelengths of light absorption. The molecular basis of spectral tuning in visual pigments, a central unsolved problem in...

Neural adaptations for dim light vision in hawkmoths

Ocellar adaptations for dim light vision in a nocturnal bee.

Growing evidence indicates that insect ocelli are strongly adapted to meet the specific functional requirements in the environment in which that insect lives. We investigated how the ocelli of the nocturnal bee Megalopta genalis are adapted to life in the dim understory of a tropical rainforest. Using a combination of light microscopy and three-dimensional reconstruction, we found that the reti...

The molecular origin and evolution of dim-light vision in mammals.

The nocturnal origin of mammals is a longstanding hypothesis that is considered instrumental for the evolution of endothermy, a potential key innovation in this successful clade. This hypothesis is primarily based on indirect anatomical inference from fossils. Here, we reconstruct the evolutionary history of rhodopsin--the vertebrate visual pigment mediating the first step in phototransduction ...