Scale worm and sea star symbiotic relationship

The species - Deep Sea Spy

scale worm and sea star symbiotic relationship

The sea star provides protection and food for the scale worm. The scale worm doesn't kill the sea star, therefore it is a commensal relationship. Commensalism or mutualism: Attraction of a sea star towards its symbiotic . New record of commensal scale worms, Arctonoe vittata (Grube, ) and and host switching in relation to its life history from the viewpoint of behavioral ecology. The sea star provides protection and food for the scale worm. The scale worm does not affect the sea star. Type of symbiotic relationship!.

Although its sister species R. This worm lives in a chitinous tube that it secretes. The tube helps protect it from predators and difficult environmental conditions. One of its strangest features is that it does not have a mouth, gut or anus. It thus has a strange way of feeding: These worms and bacteria live in symbiosis because they each depend on the other species for survival.

scale worm and sea star symbiotic relationship

The red colour of its plumes is due to the presence of haemoglobin, essential for transporting oxygen from the environment to the bacteria. Ridgeia have developed a surprising morphological adaptation to their environment with the existence of two distinct morphotypes.

They live in colonies and form so-called bushes.

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They are called engineering species because they provide habitat for smaller species that will use the worm bushes as refuges and food sources. Polynoid polychaetes scale worms Amphinomidae polychaete on the Mid-Atlantic Ridge Branchipolynoe seepensis a polychaete worm living inside the mussel Bathymodiolus azoricus Polychaete worms are exclusively marine annelid worms. The term polychaete comes from the numerous hairs that are found on each segment.

In contrast, the common earthworm in our gardens is an oligochaete because it does not have any hairs. Polychaetes are only found in marine environments. Within the polychaetes, polynoids are a highly diverse family that includes species with elytra — plates or scales — that more or less cover the body. There are at least 24 species of scale worms associated with hydrothermal vents called endemic species that are found in high abundance in animal communities.

They are generally small, making their observation on video images difficult, but the most advanced spies will learn to spot them rapidly with a little experience! They are carnivorous or grazing species depending which family they belong to. They use their tubular mouthparts, called a proboscis, that they evert to attack their prey and graze on the substrate.

This diversity of food sources allows several species to cohabit in the same area, partitioning thus the resources: The individuals observed in the middle of tube-worm bushes belong primarily to two species: Only sampling and identification in the laboratory can tell them apart.

The differences often lie in the shape and the number of hairs as well as the morphology of their mouth parts. Ophiuroids brittle stars Ophiuroids, also known as brittle stars, belong to phylum Echinodermata echinodermsalong with sea urchins, sea stars, sea cucumbers and sea lilies.

  • Describe the symbiotic relationship between a Scale worm and a Seastar.?
  • The species
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They can be identified by their five slender, flexible arms that they use to move. All of their organs are located in the central disk; on the underside is found the mouth, usually armed with five toothed jaws. The species that are found in the Lucky Strike mussel beds are not well known and are no larger than a couple of millimetres. Only two species have been described in hydrothermal fields on the Mid-Atlantic Ridge and it is very difficult to tell them apart in a video image.

scale worm and sea star symbiotic relationship

Thus, we know little about their biology and their ecology. Tunnicliffe This species is a pycnogonid sea spiderwhich belongs to phylum Arthropoda animals with jointed appendages. Pycnogonids are closely related to spiders, and have a very similar morphology!

We know little about this species. They live in groups, which helps increase the efficiency of oxygen circulation in their lymph. A recent study conducted in our laboratory showed that their behaviour follows the rhythm of the tides, thereby anticipating the environmental changes caused by the tides.

Even in the depths, tides can influence animal behaviour!! Tides act directly on current direction and intensity. Thus, we think that according to the environmental conditions, pycnogonids migrate to the centre of the tube-worm bush to feed and hide from predators and then move back to the surface of the bush to find more favourable conditions when the influence of the hydrothermal fluid is too intense.

scale worm and sea star symbiotic relationship

This species is only known on the Mid-Atlantic Ridge hydrothermal vents, but another species belonging to the same genus was recently discovered on a hydrothermal site in the Indian Ocean near Rodrigues. It feeds on organic particles found in the water column, such as debris left by mussels or animal remains.

scale worm and sea star symbiotic relationship

Experimental observations in aquariums show that they feed on exuviae exoskeletons shed after moulting left on the bottom. Some individuals travel away from the active zones at distances of up to several meters. They thus become prey to fish or even hydrozoans sessile polyps attached to the rocky substrate.

Sri Lanka,ශ්‍රී ලංකා,Ceylon,Coral Reef (18)

Segonzacia mesatlantica The bythograeid crab Segonzacia mesatlantica from the mid-Atlantic ridge Ifremer This Bythograeidae crab is characteristic of hydrothermal sites on the Mid-Atlantic Ridge. This highly mobile species is found in a wide variety of habitats, from smokers to diffuse vent areas where mussel beds develop. This distribution is attributed to its opportunistic behaviour, because it feeds on cadavers such as mussels, shrimp or shrimp exuviae exoskeletons shed after moulting.

Although it is a poor predator, it can also feed on live mussels after breaking their shells with its claws. Segonzacia crabs are solitary and territorial animals. They measure 3 to 6 cm and are white to pinkish yellow in colour. Tunnicliffe This species is not a spider, but a crustacean that belongs to the same family as the spider crabs that are fished along our shores.

Their name comes from their morphology that is similar to that of spiders with long legs and thin claws. Although this North Pacific species is also found in habitats other than hydrothermal vents, it frequents the deep sea where it feeds on various hydrothermal organisms.


They possess a number of features to help prevent other lifeforms from taking up residence on their dorsal surface. The ventral or underside however is different. Here are found the numerous tube feet used for locomotion and attachment. They are located in the ambulacral grooves that radiate out along each of the arms from the central oral disc, one per arm. Various species of small shrimps, pearlfishes and polychaete worms take up residence on the underside of sea stars for protection even burrowing into the ambulacral grooves to conceal themselves completely.

Asterophilia carlae is a polychaete belonging to the polynoid worms also known as scale worms that reside underneath sea stars. They are covered by scales called elytra which are separate from and not to be confused with the bristles called chaeta. In some species these are hard but in Asterophilia carlae they are soft and transparent. Colour is normally in accordance with the ventral colour of the host helping to further camouflage its presence however I have photographed them upon contrastingly coloured hosts as well.

Polychaetes that live in a symbiotic relationship are relatively rare in proportion to the overall number of species.