Anemones, corals, and small crustaceans are all feed on by fireworms. They remove coral tissue right from the skeleton by engulfing the last few centimeters of the tip of a branching coral.
The bearded fireworm is found in the tropical Atlantic Ocean and Mediterranean Sea. It lives on hydrothermal vents and cold seeps where it feeds on chemosynthetic bacteria and archaea. This species is very similar to the related Hermodice longicornis, but differs in having a shorter proboscis and longer tentacles, and in being smaller overall.
Bearded fireworm – Phylum Annelida; Order Polychaeta; Family Nereididae; Genus Leptotrachela
A bearded fireworm is a species of polychaete annelid worm found in marine waters throughout the world. This worm is named for its beard, which is composed of long hairs called chaetae. A typical specimen measures about fifteen centimeters in total length, although specimens up to thirty centimeters have been recorded.
The body is divided into a head, thorax, and abdomen. The head bears a cluster of three eyes, one pair of antennae, and four pairs of tentacular cirri. The thoracic appendages include six pairs of walking legs, arranged in three rows along the midline of the worm. These appendages bear short, blunt claws and are covered with numerous small sensory papillae. On either side of the middle row of legs, there are five pairs of smaller appendages known as paranota, which function as parapodia and allow the animal to move forward while remaining stationary. The abdominal appendages consist of eight pairs of parapodia, which are used for swimming. In addition, the animal carries a pair of anal cirri near the end of the abdomen.
The worm’s mouth is surrounded by a ring of long tentacles, which serve as a filter for plankton and detritus. Smaller tentacles surround the mouth, forming a collar around the pharynx. The pharynx contains a muscular pouch, which acts as a pump to draw water into the gut.
The anus lies just behind the posterior end of the body. The reproductive organs consist of a large genital opening, which leads directly into the cloaca, and a single ovary. The testes are attached to the sides of the body, and the eggs pass out through the cloaca.
This worm feeds primarily on detritus, such as dead algae, diatoms, and bacteria. However, it is omnivorous and consumes live organisms ranging from microscopic protozoans to fish larvae.
Bearded fireworms spend most of their lives buried in sediment or burrowed deep within rocks, where they feed on particles of food trapped in the sediment. They are active during daylight hours, typically feeding at night.
Appearance and Behavior
The appearance of the fireworm is quite variable. Some individuals are about 10 cm long, while others can grow much longer. In general, however, the worms are cylindrical, slender and slightly flattened dorsoventrally. Their coloration ranges from light brown to dark greyish brown.
On each side of the body there is a row of large, thin, whitish bristles. These bristles are used to defend against predators. When touched, they inflate like balloons and stick into the skin. If the worm is handled, the bristles come loose and remain attached to the skin.
When the worm is disturbed, it produces a very strong burning pain. This is caused by the release of a toxin called pareurythine, which is stored in special glands along the spine. The toxin causes severe inflammation and leads to swelling of the affected tissue. As a consequence, the surrounding skin becomes red and swollen.
In addition to the poison bristles, some specimens possess another type of defense mechanism. A small number of nerve cells are located near the spinal cord, where they control the muscles responsible for inflating the bristles. When the worm senses danger, these neurons send
Fireworms are one of the most fascinating animals at Sea Life Sydney Aquarium. This species feeds exclusively on the tissues of living hard and soft corals. When it takes food from a coral, it starts out by wrapping itself around the base of the coral polyp. Then, it begins to ingest the tissue just above the polyp. Once it gets to the end of the polyp, it wraps its body around the last few centimeters of its prey. After about ten minutes, the worm releases the polyp from its grasp and moves away.
When you look closely at a fireworm, you’ll notice that it looks like a giant white slug. However, it is actually covered in tiny black spots. Each spot represents a single mouth opening that allows the worm to eat. You might think that the worm could swallow the entire polyp, but that isn’t possible because the worm’s pharynx is too narrow. Instead, the worm removes the tissue directly from the skeleton.
The fireworm uses its tentacles to sense what it needs next. If there is no tissue left, the worm retracts its tentacles and waits patiently for another meal.
While many people enjoy watching fireworms, they don’t usually want to touch them. But, we do allow visitors to hold a live specimen during our Feeding Time presentations.
Fireworms are hermaphrodites, meaning they possess both male and female reproductive organs. They reproduce asexually, splitting apart into multiple smaller individuals called “fragments.” These fragments can either become females that produce eggs, or males that release sperm. This process is known as oogenesis or spermatogenesis. As soon as the fragment splits off, it begins growing toward the light source. Once it gets close enough, it releases a chemical signal that attracts potential mates. If the fragment finds a mate, it attaches itself to the surface of the partner and starts secreting pheromones. When the partners come together, the fireworm releases another chemical signal that triggers egg production. Each individual produces about 10 million eggs per hour, and each one takes approximately five minutes to mature. After fertilization, the larvae hatch and begin feeding on bacteria, algae, and detritus.
The polychaete worm family includes about 20 species known to live near the surface of the sea floor. Most of these worms are small, ranging in length from 4 mm to 10 cm, although some grow up to 30 cm long. All members of the group have a similar body plan, with a head, trunk, and appendages. Some species have tentacles while others lack them; most have tiny eyespots but some have large ones. All have a pair of parapodia (modified segments) along each side of their bodies. In addition to the parapodia, many species have chaetae (bristles), which aid in locomotion.
Polychaetes are often called “annelid worms,” because they resemble the segmented worms commonly referred to as Annelida. However, there are major differences between the groups. For example, the polychaetes have a single digestive tube, whereas the segmented worms have several tubes. Also, the polychaetal mouth opens directly onto the outside of the body rather than being internal like it is in the segmented worms. Another difference is that polychaetes are hermaphrodites, whereas the segmented worm species are usually male/female pairs.
Many polychaetes feed on detritus such as dead algae or plant material. Others eat bacteria or even other polychaetes. A few species are predators, feeding on crabs, shrimp, fish, mollusks, jellyfish, and cephalopods. Many species are parasites, attaching themselves to larger animals and drawing nutrients out of their tissues. Polychaetes are important in marine ecosystems because they play a role in recycling carbon dioxide into oxygen. This process occurs naturally in seawater, but polychaetes contribute greatly to this process.