Night Vision
This species possesses good night or scotopic vision. Its eye includes two different kinds of ommatidium; each contains nine light sensitive cells, of which seven contain a pigment whose absorption spectrum peaks in the green part of the spectrum, but in one type the remaining two receptors have peak absorption in the blue and in the other type they have peak reception in the ultra violet. The moth therefore has the cellular prerequisites for trichromatic colour vision. Adults have been shown to be capable of making colour discriminations at night-time levels of illumination, and they sustain these discriminations despite changes in the spectral content of the incident light; that is, they show colour constancy.
Read more about this topic: Deilephila Elpenor
Famous quotes containing the words night and/or vision:
“The night is itself sleep
And what goes on in it, the naming of the wind,
Our notes to each other, always repeated, always the same.”
—John Ashbery (b. 1927)
“Deep in the human heart
The fire of justice burns;
A vision of a world renewed
Through radical concern.”
—William L. Wallace (20th century)