Application of intracellular optical techniques to the study of stomatopod crustacean vision

1.	The noninvasive techniques of intracellular optical physiology were used to measure reflectance changes in the deep pseudopupils of various regions of the apposition compound eyes of 3 species of stomatopod crustaceans.
2.	Upon exposure to light, prominent changes in reflectance were observed in all eye regions of all species studied. Generally, the response was an increasing reflectance following stimulus onset; however, in the lateral rows of the central ommatidial band of gonodactyloid stomatopods, the response was a rapid decrease in reflectance. Halftimes for the normal, increasing response were about 5 s in the gonodactyloid species and an order of magnitude longer in the squilloid species.
3.	The reflectance changes were probably produced by pupillary mechanisms similar to those previously described for insects. Evidence for this included the form and speed of the response, the observation that fluorescence from the visual pigment diminished with a similar time course to the increase in reflectance, and the tendency of the response to sensitize to repeated stimulation.
4.	Two spectral classes of photoreceptor were distinguishable in both the peripheral and central band regions of the eye. These classes were most sensitive to ultraviolet (360 nm) or long-wavelength (500 nm) light. The classes were distinguishable by the form and speed of the reflectance changes they produced when stimulated. Results of univariance experiments suggested that only these 2 classes existed in each eye region examined.
5.	In all species and ocular regions examined, the reflectance-change response operated over an intensity range of 3–4 orders of magnitude.