Common name: Solar-powered Phyllodesmium

General information

Phyllodesmium longicirrum, commonly known as the Solar Powered Nudibranch, is a fascinating species of sea slug within the family Facelinidae. This species is renowned for its unique ability to harbor zooxanthellae, the symbiotic algae also found in corals, within its tissues. The nudibranch's cerata, which are the finger-like appendages on its body, are often translucent, allowing light to reach the algae for photosynthesis. This remarkable adaptation not only gives the nudibranch its common name but also provides it with additional nutrients, as it can utilize the sugars produced by the algae.

Care

Caring for Phyllodesmium longicirrum in a home aquarium requires an advanced level of expertise. These nudibranchs are specialized feeders, often consuming only specific types of soft corals, such as Xenia or Alcyonium. It's crucial to provide them with a continuous supply of their preferred food source, as they will not adapt to alternative diets. The aquarium should have stable water conditions, low nitrate levels, and moderate lighting to support the photosynthetic needs of the zooxanthellae.

Reproduction

Phyllodesmium longicirrum is a hermaphrodite, possessing both male and female reproductive organs. They can engage in reciprocal mating, where both individuals exchange sperm to fertilize their eggs. The eggs are laid in a gelatinous spiral ribbon and will hatch into free-swimming larvae that eventually settle and metamorphose into juvenile nudibranchs.

Symbiosis

The symbiotic relationship between Phyllodesmium longicirrum and zooxanthellae is a prime example of mutualism. The nudibranch provides a safe habitat and access to light for the algae, while in return, it receives nutrients from the photosynthesis process. This relationship allows the nudibranch to survive in nutrient-poor environments where other food sources are scarce.

Habitat

Phyllodesmium longicirrum is typically found in tropical and subtropical waters, often associated with coral reefs where its food sources, soft corals, are abundant. They are usually observed at depths where light penetration is sufficient for photosynthesis to occur, aiding their symbiotic algae.