Decorator crab and sponge relationship questions


decorator crab and sponge relationship questions

Marine symbiotic relationships are an amazing part of nature! struck between the decorator crab and the sponges that it decorates itself with. And the relationship is not limited to a certain sponge species, these and shells (think hermit crabs) to mask their identity on the sea floor. makes decorator crabs an ideal group in which to study the adaptive consequences phylogenetic relationships, provide grist for hypothesis testing about the . sponges p rovide some form of chemical or morpholog ical defence crabs as model systems to address questions of camouflage evolution.

A typical sponge decorator crab can attach fragments of sponges to their body and some reports show even attachment of sea anemones along with sponges. While decorator crabs move on top of a sponge colony, they camouflage perfectly and are totally concealed from predators.

Front view where eyes and antennae can be seen Another important species of sponge decorator crab is Hyastenus elatus. This variety shows worldwide distribution but its diversity is more in the Indo-Pacific region. For Composcia sp, the pincers or the claw is the only place devoid of any sponge attached! The presence of decorator crabs is often unnoticed during the day time because they prefer to hide in crevices or holes in coral reefs.

However, the species is very active during the night and towards dawn and dusk when illumination is less.

decorator crab and sponge relationship questions

Decorator crabs are carnivorous, feeding on a wide diversity of organic matter and marine fauna. They hunt down their invertebrate prey during the night time.

decorator crab and sponge relationship questions

The attachments found on decorator crabs play a dual role. It aids in easy concealment and at the same time, due to the distasteful nature of sponges this is because of the presence of some metabolitespredators dislike coming near the sponge decorator crab. Anemone also remain vibrant from the constant aeration generated by the movement of the clownfish.

Barnacles on a gray whale in Hare Eye Lagoon, Mexico. Ken-Ichi Ueda Barnacles and Whales Barnacles have worked out a good deal with whales, mainly humpbacks, reaping great rewards from attaching themselves to the belly or backs of the whales.

5 Symbiotic marine relationships – Marine Wildlife Magazine

Barnacles are filter-feeders, relying on plankton that they filter through feather-like appendages that extend through holes in their shells. An added benefit is protection from predators, as only the most courageous of predators is likely to attack a whale. For the most part, the whale remains unaffected—they can support the weight of thousands of barnacles at a time. Barnacles and whales are an example of a symbiotic relationship of commensalism. A seeing-eye fish Photo Credit: Klaus Stiefel Pistol Shrimp and Gobies Although the tiny pistol shrimp is basically blind, it has enlisted the help of the bottom-dwelling goby to act as its eyes and ears.


The pistol shrimp spends its days digging small burrows in the sandy seafloor searching for food. By doing so, the pistol shrimp creates holes that are just the perfect size to provide a resting place and protective shelter for a goby. The pistol shrimp allows the goby access to the holes it digs—rent-free—as long as the goby completes one job in return: When a predatory fish approaches the goby flicks its tail several times, alerting the shrimp to the coming danger.

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Both the goby and shrimp retreat deep into the burrow to wait out the attack. A decorator crab shows its style in the latest fashion. The decorator crab snips off pieces of sponge and anemone to add to its shell, gaining a piece of camouflage in the case of a sea sponge or a handy weapon in the case of a poisonous anemone.

decorator crab and sponge relationship questions

The sea sponge and anemone both continue to live on the back of the decorator crab and, like a barnacle, gain the benefit of being transported to different feeding areas.