Barnacle Eating Dorid
by Hailey Surgin
Common Name: Barnacle Eating Dorid
Scientific Name: Onchidoris bilamellata
Size Range: 6 mm(0.25 in) up to 30 cm(12 in)
Most Barnacle Eating Dorids have a mottled grey and brown colour to them. Their mantle, which is an outer layer of tissue that contains the viscera and secretes the substance that puts together the shell in other molluscs, has a brown and white pattern on it. Young dorids, and some mature adults may be completely white. Towards the head are white club shaped tentacles called rhinophores. They also have a circular gill plume near their posterior.
Throughout all the regions that Barnacle Eating Dorids live, they are all very similar. They are all sublittoral, which refers to a region that is near the shore where animals inhabit and grow as well as the area from the shore that reaches out to one hundred meters. The depth of these areas can be up to twenty meters below sea level.
The Barnacle Eating Dorid, as mentioned in it’s name, really only eats one thing. Barnacles. The way that they eat the barnacles is by drilling into it with a specialized radula. Other parts of it’s diet also includes sponges, anemones, and coral.
There is little information about specific predators of this species. However, when they are disrupted or disturbed, they secrete acids that act as deterrents.
Not a great deal of information is known about this specific nudibranch, but most nudibranchs are simultaneous hermaphrodites. A simultaneous hermaphrodite is an organism that can mate with any other mature male or female of their species as they have both male and female reproductive organs. When Onchidoris bilamellata reproduces, they come together in large groups to mate and lay eggs in shallow water. The life span of a nudibranch varies widely. Some live for a month, whilst others can live for almost a year.