Scientists from and Vietnam identified the nature of the relationship between crinoids from the order Comatulida and their symbionts as commensalism. Comatulid was tasteless fish, while the symbionts they eat willingly. Probably, the inhabitants of crinoids attract predators, so comatulid become tasteless as protection, but at the same time and turned into a profitable refuge for the commensals. Article published in the journal Scientific Reports.
Sea lilies from the squad Comatulid (Comatulida) lead a sedentary lifestyle. They can’t run away or hide from predators, so these animals have to invent other ways of protection. Sea lilies become hard, develop the ability to regenerate and secrete toxic substances. The researchers noticed that the fish avoid eating sea lilies, and then confirmed experimentally that the taste comatulid unpleasant for the fish.
However, fish from time to time attack on a sea of lilies. Probably, they are attracted to the symbionts, who are hiding in a branchy hands comatulid. Such symbionts on the same lilies can be over fifty and they belong to dozens of different types. On comatulid live polychaetes, gastropods, crabs, shrimp, and a brittle star fish.