Lettuce Sea Slug on Discosoma
This lettuce sea slug (Elysia crispata) was cruising over a few Discosoma sanctithomae and D. neglecta polyps on its way to a patch of Bryopsis sp. algae in one of the holding tubs in the Morphologic Lab. It measures approx. 3cm in length.
The lettuce sea slug (Elysia crispata) is not a true nudibranch, as it is often referred, but a ‘sacoglossan sea slug’. Sacoglossans feed by sucking out the chlorophyll contents of algae, and then incorporate that chlorophyll into their own tissues. Thus the slugs themselves become ‘solar powered’.
Elysia crispata are native across the Caribbean and prefer to feed on Caulerpa species algae like C. verticillata and C. sertularioides. In an aquarium, when deprived of these preferred species, they will consume the pest hair algae Brysopsis sp. that most other herbivores avoid.