Multiple mechanisms of rhabdom shedding in the lateral eye of Limulus polyphemus.

Rhabdom shedding in horseshoe crab lateral eye photoreceptors was studied with anti-opsin and anti-arrestin immunocytochemistry. Two, possibly three, distinct shedding mechanisms were revealed in animals maintained in natural lighting. Transient rhabdom shedding, triggered by dawn, is a brief, synchronous event that removes up to 10% of the rhabdom membrane.

Spatial control of photomechanical movements in the lateral eye of the American horseshoe crab, Limulus polyphemus.

This study asks whether photomechanical movements in the retinal cells of the lateral eye of the American horseshoe crab, Limulus polyphemus, are controlled locally within each ommatidium, or whether they are a retinal array property involving lateral communication between ommatidia. Three experiments were performed. A small spot, a vertical slit down the center, or the anterior third of an otherwise masked eye was illuminated.