Molluscs play a variety of roles in culture, including but not limited to art and literature, with both practical interactions—whether useful or harmful—and symbolic uses.
Harmful interactions with molluscs include the stings of cone snails and the venomous bites of certain octopuses; blue-ringed octopuses bite only when provoked, but their venom kills a quarter of the people bitten. Some snails are vectors of diseases such as schistosomiasis, a major tropical disease that infects some 200 million people; others are serious crop pests, and species such as the giant East African snail Lissachatina fulica have damaged ecosystems in areas where they have been introduced.
Mollusc shells have been widely used in art, whether carved directly, sometimes as cameos, or depicted in paintings.
In popular culture, the snail is known for its stereotypical slowness, while the octopus and giant squid have featured in literature since classical timesasmonsters of the deep. Many-headed and tentacled monsters appear as the Gorgon and the MedusaofGreek mythology, and the kraken of Nordic legend. The taxonomistCarl Linnaeus named the Venus shell as Venus dione, for the goddess of love and her mother, and named its parts using overtly sexual descriptors.
Most molluscs with shells can produce pearls, but only the pearls of bivalves and some gastropods, whose shells are lined with nacre, are valuable.[5][6] The best natural pearls are produced by marine pearl oysters, Pinctada margaritifera and Pinctada mertensi, which live in the tropical and subtropical waters of the Pacific Ocean. Natural pearls form when a small foreign object gets stuck between the mantle and shell.
Pearls for use as jewellery are cultured by inserting either "seeds" or beads into oysters. The "seed" method uses grains of ground shell from freshwater mussels, and overharvesting for this purpose has endangered several freshwater mussel species in the southeastern United States.[6] The pearl industry is so important in some areas, significant sums of money are spent on monitoring the health of farmed molluscs.[7]
Tyrian or imperial purple, made from the ink glands of murex shells, "... fetched its weight in silver" in the fourth century BC, according to Theopompus.[31] The discovery of large numbers of Murex shells on Crete suggests the Minoans may have pioneered the extraction of "imperial purple" during the Middle Minoan period in the 20th–18th centuries BC, centuries before the Tyrians.[32][33]
Sea silk is a fine, rare, and valuable fabric produced from the long silky threads (byssus) secreted by several bivalve molluscs, particularly Pinna nobilis, to attach themselves to the sea bed.[34]Procopius, writing on the Persian wars circa 550 CE, "stated that the five hereditary satraps (governors) of Armenia who received their insignia from the Roman Emperor were given chlamys (or cloaks) made from lana pinna. Apparently, only the ruling classes were allowed to wear these chlamys."[35]
Peoples of the Indian Ocean, Pacific Ocean, North America, Africa and the Caribbean have used shells as money, including Monetaria moneta, the money cowrie[36] in preindustrial societies. However, these were not necessarily used for commercial transactions, but mainly as social status displays at important occasions, such as weddings.[37] When used for commercial transactions, they functioned as commodity money, as a tradable commodity whose value differed from place to place, often as a result of difficulties in transport, and which was vulnerable to incurable inflation if more efficient transport or "goldrush" behaviour appeared.[38] Among the Eastern Woodlands tribesofNorth America, shell beads known as wampum were kept on strings and used as money.[39][40][41]
Bivalve molluscs are used as bioindicators to monitor the health of aquatic environments in both fresh water and the marine environments. Their population status and structure, physiology, behaviour and their levels of contamination with chemicals together provide a detailed indication of the status of the ecosystem. Because they are sessile, they serve as readily-monitored representatives of their environment.[42]
A few species of molluscs, including octopuses and cone snails, can sting or bite. Some present a serious risk to people handling them. However, deaths from jellyfish stings are ten times as common as those from mollusc bites.[44]
Live cone snails can be dangerous to shell collectors, but are useful to neurology researchers.[45]
All octopuses are venomous,[46] but only a few species pose a significant threat to humans. Blue-ringed octopuses (Hapalochlaena) from Australia and New Guinea have a powerful venom and warning coloration. They bite humans only if severely provoked,[43] but their venom kills a quarter of the people bitten. Another tropical species, Octopus apollyon, causes severe inflammation that can last for over a month even if treated correctly.[47] The bite of O. rubescens can cause necrosis that lasts longer than one month if untreated, and headaches and weakness persisting for up to a week even if treated.[48]
All marine cone snails are venomous and can sting when handled. Their venom is a complex mixture of toxins, some fast-acting and others slower but deadlier.[45] Many painful stings have been reported, and a few fatalities.[44] Only a few larger species of cone snails are likely to be seriously dangerous to humans.[49] The effects of individual cone-shell toxins on victims' nervous systems are so precise as to be useful tools for research in neurology, and the small size of their molecules makes it easy to synthesize them.[45][50]
Molluscs are vectorsofparasitic diseases such as schistosomiasis, a major tropical disease second only to malaria. It is caused by flukes, Schistosoma spp., and infects some 200 million people in 74 countries.[52] The flukes have a complex life cycle with freshwater snails as intermediate hosts; people swimming or washing in the water are at risk of infection.[53] Molluscs can also carry angiostrongyliasis, a disease caused by the worms of the Angiostrongylus spp., which can occur after voluntarily or inadvertently consuming raw snails, slugs, other mollusks and even unwashed fruits and vegetables.
Some snails and slugs are serious crop pests,[54] and in new environments can unbalance local ecosystems. One such pest, the giant African snail Lissachatina fulica, has been introduced to many parts of Asia and islands in the Indian and Pacific Oceans, reaching the West Indies in the 1990s. The predatory snail Euglandina rosea was disastrously introduced in an attempt to control it, as the predator ignored A. fulica but extirpated several native snail species instead.[55]
The snail features in an animal epithet for its stereotypical slowness,[56] while its shell-less relative the slug similarly denotes a person who is lazy and loathsome.[57]
Throughout the world, the nautilus is captured to carve the elegantly shaped shells, and for their nacreous inner shell layer, a pearl substitute.[64][65][66]Mother-of-pearl or nacre, which lines some mollusc shells, is used to make organic jewellery. It has traditionally been inlaid into furniture and boxes, particularly in China. It has been used to decorate musical instruments, watches, pistols, fans and other products.[67] Shells have been used in Southern Italy as a cheaper alternative to layered stone when carving cameos.[68] In the fine art of the Italian Renaissance, Sandro Botticelli's c. 1486 The Birth of Venus depicts the goddess Venus emerging from the waves on a scallop shell.[69] In the Dutch Golden Age, still life painters such as Adriaen Coorte often depicted ornate sea shells of varied kinds in their compositions.[70]
Nautilus shell carved and painted with fanciful scenes of human figures and animals
In his 1758 Systema Naturae, and then in his 1771 Fundamenta Testaceologiae, the pioneering taxonomist Carl Linnaeus used a series of "disquieting[ly]"[71] sexual terms to describe the Venus shell: vulva, anus, nates (buttocks), pubis, mons veneris, labia, hymen.[71][72][73] Further, he named the species Venus dione, for Venus, the goddess of love, and Dione, her mother. The evolutionary biologist Stephen Jay Gould called Linnaeus's description "one of the most remarkable paragraphs in the history of systematics".[71][74] Some later naturalists found the terms used by Linnaeus uncomfortable; an 1803 review commented that "a few of these terms however strongly they may be warranted by the similitudes and analogies which they express, ... are not altogether reconcilable with the delicacy proper to be observed in ordinary discourse",[71] while the 1824 Supplement to the Encyclopædia Britannica criticised Linnaeus for "indulg[ing] in obscene allusions."[71]
^James Arnold Higginbotham, Piscinae: artificial fishponds in Roman Italy (University of North Carolina Press, 1997), p. 247, note 44 online; Cynthia J. Bannon, "Servitudes for Water Use in the Roman Suburbium," Historia 50 (2001), pp. 47–50. For more on these early efforts, see Sergius Orata.
^"Mollusks". Food & Wine. Retrieved 20 January 2018. These amazing recipes include foie gras steamed clams and cavatelli with mussels, lillet, and dill.
^Spoiden, Stéphane (2001). "The Betrayal of Moules-frites". In Schehr, Lawrence R.; Weiss, Allen S. (eds.). French Food: On the Table, On the Page, and in French Culture. Routledge. p. 162 and throughout. ISBN978-0415936286.
^The fourth-century BC historian Theopompus, cited by Athenaeus (12:526) around 200 BC, according to Gulick, C.B. (1941). Athenaeus, The Deipnosophists. Harvard University Press. ISBN978-0-674-99380-8.
^Reese, D.S. (1987). "Palaikastro Shells and Bronze Age Purple-Dye Production in the Mediterranean Basin". Annual of the British School of Archaeology at Athens. 82: 201–6. doi:10.1017/s0068245400020438. S2CID129588313.
^Hogendorn, J.; Johnson, M. (2003). The Shell Money of the Slave Trade. Cambridge University Press. ISBN978-0521541107. Particularly chapters "Boom and slump for the cowrie trade" (pages 64–79) and "The cowrie as money: transport costs, values and inflation" (pages 125–147)
^Dubin, Lois Sherr. North American Indian Jewelry and Adornment: From Prehistory to the Present. New York: Harry N. Abrams, 1999: 170–171. ISBN0-8109-3689-5.
^Jacobs, Jaap. The Colony of New Netherland: A Dutch Settlement in Seventeenth-century America. Cornell University Press, 2009. pg. 14
^Civeyrel, L.; Simberloff, D. (October 1996). "A tale of two snails: is the cure worse than the disease?". Biodiversity and Conservation. 5 (10): 1231–1252. doi:10.1007/BF00051574. S2CID43071631.
^"Slug". Oxford Dictionaries. Archived from the original on September 25, 2016. Retrieved 12 July 2017. 2. A slow, lazy person. "'Even though you're dying to bitchslap your clueless roommate, loser boyfriend or loathsome slug of a boss, play nice.'"
^De Angelis, Patricia (2012). "Assessing the impact of international trade on chambered nautilus". Geobios. 45: 5–11. doi:10.1016/j.geobios.2011.11.005.
^Freitas, B.; Krishnasamy, K. (2016). An Investigation into the Trade of Nautilus. TRAFFIC.
^Mack, Charles R. (2002),"Botticelli's Venus: Antique Allusions and Medicean Propaganda," Explorations in Renaissance Culture, 28, 1 (Winter), 2002, 1–31.
^Gould, Stephen Jay (1995). "The Anatomy Lesson: The Teachings of Naturalist Mendes da Costa, a Sephardic Jew in King George's Court". Natural History. 104 (12): 10–15, 62–63.