Bloodworm
Bloodworms are aquatic worms belonging to the family Glyceridae, known for their striking blood-red coloration and habitat in muddy environments worldwide. These organisms are primarily found in freshwater and saltwater, thriving in diverse aquatic conditions, including estuaries and tidal zones. The genus Glycera comprises various species, each characterized by a segmented body that can reach lengths of up to 14 inches (35.5 centimeters). Bloodworms possess a clitellum, a feature they share with earthworms, which plays a role in their unique reproductive process as hermaphrodites.
Living primarily in the upper layers of mud, bloodworms feed on bacteria and decomposing organic material. They are equipped with bristles that aid their movement through their burrows, and they have developed a specialized system to extract oxygen from the low-oxygen environments in which they thrive. Notably, they use their tails to draw water into their burrows to aid in respiration. Bloodworms are a key food source for various fish species and are also commonly used as bait by fishermen. They have a life span of about three years, with the potential to live up to five years, and are not currently considered a threatened species.
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Bloodworm
There are many species of worms in the family Glyceridae, commonly known as bloodworms. They are known worldwide for their blood-red colors and their appearance in muddy habitats. Bloodworms may live in freshwater and saltwater habitats, as well as in water with various salt concentrations, such as tidal zones.
Kingdom: Animalia
Phylum: Annelida
Class: Polychaeta
Order: Phyllodocida
Family: Glyceridae
Genus: Glycera
Species: Various (see below)
There are many species of worms in the genus Glycera, commonly known as bloodworms. Muddy bottoms in waterways and coastal regions around the world are homes to the family of earthworms known as bloodworms. All of the dozens of species in this family burrow into the upper layers of mud in various aquatic, or water, habitats. Some bloodworm species live in marine, or ocean, habitats. They are found most often in shallow waters near the shore. Other species burrow into the muddy bottoms of estuaries. Estuaries are the areas where freshwater rivers and saltwater tides meet and mix. Still other species are found in freshwater rivers, lakes, and ponds. Some are even able to survive in polluted and foul water. Bloodworms often are found under stones and among weeds in the mud. Their burrows, which are tubes of mucus which their bodies secrete, are covered with mud.
Even though they live in the water, these species have certain features more in common with earthworms than with worms in the class Polychaeta. Like other earthworms, each bloodworm's body has many segments. An adult bloodworm may have 112 to 130 ring-like segments. Except for the first and the last segments, each segment of a bloodworm's body has four bunches of bristles attached to it. These bristles provide traction when a bloodworm moves. Another feature in common with earthworms and one which the aquatic polychaetae worms do not have is a clitellum. Each bloodworm has a band around its body called a clitellum, which is important for reproduction.
Bloodworms have slender bodies up to 14 inches (35 1/2 centimeters) long. They receive their name from the red hemoglobin in their blood which carries oxygen. Unlike polychaetae worms, bloodworms in this family do not have gills or blood vessels near their skin surfaces to pull oxygen from the water. Even though they live in the mud where little oxygen is available, the worms manage to breathe with their systems of blood vessels. They extend their tail ends from their burrows and constantly move their tails through the water. This action draws water down through the mud and brings the worms oxygen. The more oxygen they need, the faster they move their tails. If the oxygen content in the water is too low, the worms stop eating, empty their intestines, and use their intestines to breathe.
With their heads pointed downward in the mud, bloodworms feed on bacteria and decomposing matter in the mud. Their greatest predators are fish. Bloodworms are also popular bait with fishermen, and other people feed the worms to fish in aquariums.
Bloodworms are hermaphrodites. This means that each worm produces both sperm and eggs. When two worms mate, they exchange packages of sperm, called spermatophores, and fertilize their eggs. Sperm and eggs enter cocoons of mucus which their clitellums secrete. Each cocoon may have one to 17 eggs, usually four to nine. The eggs hatch in one to eight weeks, and those which hatch first often eat some of the other eggs. The young are 1/4 inch (five millimeters) long and have 30 to 35 segments. The young are able to mate in autumn.
Bloodworms generally live up to three years, although some may live up to five. They are not considered a threatened species.
Bibliography
Baggaley, Kate. “Bloodworm Jaws Are Full of Secrets to Sustainability.” Popular Science, 26 Apr. 2022, www.popsci.com/animals/bloodworm-fangs-sustainable-materials. Accessed 21 Mar. 2024.
Cowles, Dave. “Glycera Americana Leidy, 1855.” Invertebrates of the Salish Sea, 2018, inverts.wallawalla.edu/Annelida/Glyceridae/Glycera‗americana.html. Accessed 21 Mar. 2024.