Meeting Abstract
Copepods can serve as a model for investigations into the functions of carotenoids in animals. Previous work on Tigriopus californicus demonstrated that copepods rely on their diet to accumulate carotenoids in their bodies and suggested that, despite their red color, eyespots contained no carotenoids. When fed a carotenoid-free diet of yeast, the orange coloration of the bodies of copepods fades away while the eyespot remains a bright red color. The eyespots of copepods play an important role in many behaviors including diel vertical migration, food acquisition, and predator detection. Elucidating the mechanism behind the source and maintenance of eyespot color in copepods is therefore crucial to understanding these behaviors. Here we used Raman spectroscopy to detect the pigments present in copepods fed both normal and carotenoid-free diets. We detected the red carotenoid, astaxanthin, in T. californicus eyespots of both diet groups, as well as in the eggs and the cuticles of normal red-colored individuals. Additionally, we also identified canthaxanthin for the first time in the antennae and caudal rami of normal and diet-restricted individuals, as well as in the bodies of diet-restricted individuals. We will discuss the implications of the persistence of carotenoids in the eyespot even with no access to dietary carotenoids.
