Biology/Natural History: This species feeds on, and is often found on, red sponges such as Acarnus,Esperiopsis,Ophlitaspongia, and Plocamia. It lays its eggs in a tight orange circle on the sponges March to October. The larvae are planktonic for 30-45 days, then settle. an encounter with at least one prey sponge, Ophlitaspongia pennata, can induce larvae to settle. It is believed that its orange pigment comes from the sponge. Adults can locate and navigate to distant Ophlitaspongia sponges by smell. Some individuals seem to stay quite close to one area while others range for distant sponges. Predators may include the flatworm Notoplana acticola. The cephalaspidean predatory nudibranch Navanax inermis is repelled by secretions from Rostanga.