Honeycomb Barnacle Adaptations

The honeycomb barnacle -- scientific name Chamaesipho tasmanica -- is a crustacean found only on the coast of southeastern Australia, from New South Wales to Tasmania. The barnacle adapts throughout its life from a swimming piece of plankton to a crustacean encased entirely in protective plates formed from the barnacle's bodily secretions.

  1. Location

    • The location of the honeycomb barnacle can alter the size of a mature crustacean, ranging from just over one-quarter of an inch to around one inch. The honeycomb barnacle survives in mid-tidal areas of the southeastern Australian coast. Larger barnacles are found in deeper regions of coastal rock, according to the Marine Education Society of Australasia. Unlike other types of barnacle, which survive on wood and in estuaries, the honeycomb barnacle has adapted to survive solely on rock surfaces. Honeycomb barnacles use receptors to feel for a rocky surface, and the chemical composition of adult barnacles form a honeycomb structure of many barnacles.

    Feeding

    • Barnacles as a whole have adapted to use cirripeds, which are long feathery structures that move out from within the protective shell of the barnacle through a valve made up of two plates. These cirripeds are used to catch food brought to the honeycomb barnacle on the tide. Honeycomb barnacles, in particular, feed on plankton carried by the incoming tide. Because the honeycomb barnacle cannot move once it cements itself to a rock face, it becomes reliant on the tide for food.

    Life

    • The honeycomb barnacle undergoes a variety of adaptations throughout its life, beginning as a simple plankton that floats through the water searching for food. Once the larva progresses to the cyprid phase of life, it stops feeding and begins to search for a place to cement its antennae. In the case of a honeycomb barnacle this must be a rock surface. The presence of a group of other adult honeycomb barnacles indicates the place is successful for barnacle survival. As a result, many honeycomb barnacles group together in some locations so he protective plates cannot be recognized as individual. Once the barnacle is cemented into place, it protects itself by adapting to the environment with the secretion of four main shell plates.

    Valve

    • During periods where the honeycomb barnacle is not covered by water, the crustacean adapts to its environment by closing the two plates that cover the surface opening for feeding. This allows the barnacle to survive without losing water through the valve, according to researchers at Barwon Bluff Marine Sanctuary. When covered by the tide, the top opens again to allow feeding and water to envelope the barnacle.