Compound eyes: localization of two color receptors in the same ommatidium.

The compound eye of the cockroach Periplaneta has receptors for ultraviolet light (maximum sensitivity at 365 nanometers) and green light (maximum sensitivity at 510 nanometers). Single photoreceptor cells in the compound eye were impaled, identified by spectral response, and marked with dye-filled microelectrodes. Using two diferent dyes, we showed that both types of receptors can be found in the same ommatidium.