Meeting Abstract
Marine crustaceans frequently experience a complex life history. In most species, a series of distinct planktonic larval stages metamorphoses into an adult that may continue to be planktonic (e.g. copepods, euphausiids) or switch to an adult lifestyle varying from nektonic (e.g. decapod shrimp, some crabs) to benthic (e.g. most crabs, lobsters, stomatopods) or even sessile (e.g. barnacles). The photosensitive organs of these larvae range from simple naupliar eyes, with one or a few optical elements, to rather complex (if tiny) compound eyes consisting of several to dozens of ommatidia (at which point they perhaps leave the realm of “low-resolution eyes”). Larval eyes often have special adaptations to reduce their visibility in natural waters, some of which are optically novel. At the time of metamorphosis, the optical system of larval compound eyes changes from the characteristic transparent apposition type to an early adult eye of a different type, most often to a standard apposition eye or a type of superposition eye. This can occur by enlargement and rather simple remodeling or can require the replacement of the larval eye with a completely new adult retina and optical system (as in stomatopods). Crustacean larval eyes contribute to many simple photobehaviors which vary with the particular environment in which the larva finds itself. Many crustacean larvae are highly competent predators, and their eyes likely foster a genuine visual sense for detection, identification, and localization of prey (and possibly predators as well). Larval visual ecology and the neurobiology of larval crustacean vision continue to be areas of active research.
