COMPOUND EYES AND OCULAR PIGMENTS OF CRUSTACEAN LARVAE (STOMATOPODA AND DECAPODA, BRACHYURA)

Larvae of decapod and stomatopod crustaceans possess paired compound e yes not unlike those of adult crustaceans. However, the visual demands of larval and adult life differ considerably. Furthermore, the eyes o f adult stomatopods appear to be far more specialized than those of th e larvae. We examined eyes of several stomatopod species just before a nd after larval metamorphosis. At this time, the entire larval retina is joined by a new, adult-type retinal array which gradually replaces the remnants of the larval retina. The new retina of the postlarva is anatomically similar to that of the full-grown adult, acid has virtual ly identical assemblages of intrarhabdomal filters. We determined the photopigments of Gonodactylus aloha, the only species for which we wer e able to obtain both larval and adult specimens, using microspectroph otometry. The single middle-wavelength larval rhodopsin (lambda(max) = 499 nm) disappears at metamorphosis; none of the 10 classes of adult rhodopsins has lambda(max) between 473 and 510 nm. This metamorphic ch ange of visual pigment does not occur in a comparison species of decap od crustacean, the blue crab Callinectes sapidus. Here, rhodopsins bot h of the megalops larva and the adult had lambda(max) at 503-504 nm. T he difference between these two species can be explained by the varyin g ecological requirements of their larvae and adults, and more study o f visual pigments in retinas of larval and adult crustaceans is warran ted.