Glycera (annelid)

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Glycera alba (dim).jpg
Glycera sp.
Scientific classification e
Kingdom: Animalia
Phylum: Annelida
Clade: Pleistoannelida
Subclass: Errantia
Order: Phyllodocida
Family: Glyceridae
Genus: Glycera
Savigny, 1818

Many, see text

The genus Glycera is a group of polychaetes (bristle worms) commonly known as bloodworms. They are typically found on the bottom of shallow marine waters, and some species (e.g. common bloodworms) can grow up to 35 cm (14 in) in length.

Although both are visually similar and commonly used as fishing bait, bloodworms are biologically distinct from Lugworms.[citation needed]


Bloodworms have a creamy pink color, as their pale skin allows their red body fluids that contain haemoglobin to show through. This is the origin of the name "bloodworm". At the 'head', bloodworms have four small antennae and small fleshy projections called parapodia running down their bodies.[1][2] Bloodworms can grow up to 35 centimetres (14 in) in length.

Bloodworms are carnivorous. They feed by extending a large proboscis that bears four hollow jaws. The jaws are connected to glands that supply venom which they use to kill their prey, and their bite is painful even to a human. They are preyed on by other worms, bottom-feeding fish, crustacea, and gulls.

Reproduction occurs in midsummer, when the warmer water temperature and lunar cycle among other factors triggers sexually mature worms to transform into a non-feeding stage called the epitoke. With enlarged parapodia, they swim to the surface of the water where both sexes release gametes, and then die.

The first stage in many forms of bloodworm is a zooplanktonic stage followed by the benthic instar where the familiar segmented red larvae develop protected by silk tubes made in the bottom silt. These larvae progress from tiny pale opaque worms to the larger red larvae of 3 to 10 centimeters in length or longer over a period as short as 2–3 weeks in optimum conditions.[3]

These animals are unique in that they contain a lot of copper without being poisoned. Their jaws are unusually strong since they too contain the metal in the form of a copper-based chloride biomineral, known as atacamite,[4] in crystalline form.[5] It is theorized that this copper is used as a catalyst for its venomous bite. In Glycera dibranchiata, the jaws are a composite of melanin and 10% copper.[6]


Glycera is the type genus of the family Glyceridae. It contains the following species:[7]

Use by humans[edit]

Glycera worms are sold commercially in tackle shops as bait for saltwater fishing.[8]


  1. ^ Chien PK, Rice MA (1985). "Autoradiographic localization of exogenously supplied amino acids after uptake by the polychaete, Glycera dibranchiata Ehlers". Wasmann Journal of Biology. 43: 60–71. ISSN 0043-0927. OCLC 6322423.
  2. ^ Qafaiti M, Stephens GC (1988). "Distribution of Amino Acids to Internal Tissues After Epidermal Uptake in the Annelid Glycera dibranchiata" (PDF). Journal of Experimental Biology. 136 (1): 177–191. doi:10.1242/jeb.136.1.177.
  3. ^ "Bloodworm: Uses and applications as a fishing bait". Archived from the original on 2013-03-15. Retrieved 2012-12-03.
  4. ^ Lichtenegger HC, Schöberl T, Bartl MH, Waite H, Stucky GD (October 2002). "High abrasion resistance with sparse mineralization: copper biomineral in worm jaws". Science. 298 (5592): 389–92. Bibcode:2002Sci...298..389L. doi:10.1126/science.1075433. PMID 12376695. S2CID 14001250.
  5. ^ Lichtenegger HC, Schöberl T, Ruokolainen JT, et al. (August 2003). "Zinc and mechanical prowess in the jaws of Nereis, a marine worm". Proc. Natl. Acad. Sci. U.S.A. 100 (16): 9144–9. Bibcode:2003PNAS..100.9144L. doi:10.1073/pnas.1632658100. PMC 170886. PMID 12886017.
  6. ^ Lesté-Lasserre, Christa (April 25, 2022). "Bloodworms have copper jaws that could inspire self-building materials". New Scientist. Retrieved April 26, 2022.
  7. ^ Fauchald, K.; Bellan, G. (2009). Glycera Savigny, 1818. In: Fauchald, K. (Ed) (2009). World Polychaeta database. Accessed through the World Register of Marine Species at on 2009-03-12.
  8. ^ WHITTLE, PATRICK (2017-04-27). "Abating Bait: Decline in Prized Worms Threatens Way of Life". U.S. News. Archived from the original on 2018-04-21.

"Fishing for Allergens: Bloodworm-Induced Asthma" study at the Allergy, Asthma & Clinical Immunology (AACI) site [1]

  1. ^ Wu, Keith CP; Räsänen, Katja; Hudson, Thomas J. (2005). "Fishing for Allergens: Bloodworm-Induced Asthma". Allergy, Asthma & Clinical Immunology. 1 (2): 58–59. doi:10.1186/1710-1492-1-2-58. PMC 2877067. PMID 20529225.