... of photopigment-packed rhabdoms and the widening of crystalline cone apertures at night. These changes are hypothesised to adjust the light flux to the photoreceptors and to alter optical sensitivity as the eye moves between light- and dark-adapted states. Here, we compared optical sensitivity in fiddler crab...

...Barbara-Anne Battelle; Karen E. Kempler; Alexander K. Parker; Cristina D. Gaddie SUMMARY Dark and light adaptation in photoreceptors involve multiple processes including those that change protein concentrations at photosensitive membranes. Light- and dark-adaptive changes in protein levels...

... ). At night, the sensitivity is 1 log unit lower ( I 50 =10 20.2 photons m −2 sr −1 s −1 ), ensuring that the pupil is maximally open when light intensities are low. During daytime, light adaptation is completed in slightly less than 40 min, and dark adaptation takes approximately 50 min. The pupil response...