Glycera (genus)

Taxobox
name = Bloodworms

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image_width = 230px
image_caption = "Glycera sp."
regnum = Animalia
phylum = Annelida
classis = Polychaeta
ordo = Phyllodocida
familia = Glyceridae
genus = "Glycera"
subdivision_ranks = Species
subdivision = Examples:
"Glycera americana"
"Glycera dibranchiata"

The genus "Glycera" is a group of polychaetes (bristle worms) commonly known as blood worms. They are typically found on the bottom of shallow marine waters, and some species (e.g. the proboscis worm, "Glycera dibranchiata"), are extensively harvested for use as bait in fishing. Another common species is the tufted gilled bloodworm, "G. americana".

Anatomy

Bloodworms have a creamy pink color, as their pale skin allows their red body fluids 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. The parapodia also contain their gills, which they use to breathe. Bloodworms can grow up to 35 cm in length.

Ecology

Bloodworms are poor swimmers but good burrowers, living on the sandy or silty bottoms of the intertidal or subtidal regions. Though usually marine, they can tolerate low salt levels in the water, and also poor oxygen levels. Bloodworms and all water worms have adapted to life in the sand and silt for the protection it offers.

Bloodworms are carnivorous. They feed by extending a large proboscis that bears four hollow jaws. The jaws are connected to glands that supply poison which they use to kill their prey, and their bite is painful even to a human. They are preyed on by other worms, by bottom-feeding fish and crustaceans, and by 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 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 atacamiteHelga Lichtenegger, Thomas Schöberl, Galen D. Stucky et al., "High Abrasion Resistance with Sparse Mineralization: Copper Biomineral in Worm Jaws", Science 298 (2002) no. 5592 pp 389-392, doi | 10.1126/science.1075433] . And unlike the clamworm ("Nereis limbata"), whose jaws contain the metal zinc, the copper in the mineral in the jaws of "Glycera" is actually present in its crystalline formHelga Lichtenegger, Thomas Schöberl, Galen D. Stucky et al., "Zinc and mechanical prowess in the jaws of Nereis, a marine worm", PNAS August 5, 2003 vol. 100 no. 16 9144-9149, doi | 10.1073/pnas.1632658100] .It is theorized that this copper is used as a catalyst for its poisonous bite.

Use by humans

"Glycera" worms are sold commercially by nurseries and aquatic stores in both live, frozen and freeze dried form as a food for aquarium fish.

Popular culture references

In Peter Jackson's 2005 remake of "King Kong", Jack, Carl and Jimmy encounter giant "Carnictis" worms in a chasm on Skull Island, special-effects-created creatures which were clearly based on bloodworms. More than 250,000 live bloodworms were featured in the campy 1976 horror film "Squirm".

"Dirty Jobs" host Mike Rowe went digging for bloodworms in Maine in episode 5.2 from December 2006.

References