Spectral Sensitivity of Vision in the Mantis Shrimp, Gonodactylus oerstedii, Determined Using Noninvasive Optical Techniques

Abstract

Compound eyes of stomatopod crustaceans have many unique design features. Recently developed intracellular optical physiology techniques permit the measurement of spectral sensitivity functions in intact eyes of these animals. We tested four technically distinct approaches to measurement of spectral sensitivity in peripheral ommatidia of the compound eyes of Gonodactylus oerstedii. Each technique was evaluated for (1) the time required to measure a complete sensitivity spectrum, (2) reproducibility of results, and (3) suitability for use in a fully automated system. A spectral scan technique, in which the visual response is held constant by varying stimulation intensity throughout the scan, was found to be superior. With it, a complete, highly reproducible measurement of spectral sensitivity from 400 to 650 nm at 10-nm intervals could be accomplished automatically within 20 min. The photoreceptors were maximally sensitive near 540 nm, and the sensitivity curve was well described by the absorptance curve for a retinal₁-based visual pigment with peak absorbance at 537 nm and peak density equal to 0.5 OD.