indirect eyes

Definition

Eyes of certain arachnids, such as spiders, that do not form images directly but instead detect changes in light intensity, aiding in movement detection and navigation.

Etymology

From Latin 'in-' meaning 'not' and 'directus' meaning 'straight', referring to the way these eyes do not form direct images.

Example

The indirect eyes of a wolf spider help it detect shifts in light intensity, alerting it to potential movement nearby.

Synonyms

• Secondary eyes
• Lateral eyes

Related Terms

• Simple eyes
• Ocelli
• Primary eyes
• Vision

Usage Notes

Indirect eyes are often contrasted with direct or primary eyes, which form detailed images. They are typically positioned laterally on the cephalothorax of arachnids.