Question: Are caterpillars able to see?

Sarah Martin answered on 18 Jun 2012:

Hi meg123!
Caterpillars can barely see at all. They have simple eyes (ocelli) which can only differentiate dark from light using light-sensitive cells in them, but they can’t form an image. Most caterpillars have a ring of six ocelli on each side of the head.

When they pupate into butterflies and moths however, they develop compound eyes. These eyes are made up of many hexagonal lenses which focus light from each part of the insect’s field of view onto a sensitive cell. An optic nerve then carries this information to the insect’s brain. They see very differently from us; they can see ultraviolet rays (which are invisible to us).
Here’s an artist’s impression of what a scientist might look like seen through a compound eye:

🙂 Sarah