The dog whelk, dogwhelk, or Atlantic dogwinkle (''Nucella lapillus'') is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
predatory
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
sea snail
Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...
, a
carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
marine
gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
in the family
Muricidae
Muricidae is a large and varied taxonomic family of small to large predatory sea snails, marine gastropod mollusks, commonly known as murex snails or rock snails. With about 1,600 living species, the Muricidae represent almost 10% of the Neogas ...
, the rock snails.
''Nucella lapillus'' was originally described by
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
in his landmark 1758
10th edition of ''Systema Naturae'' as ''Buccinum lapillus'' (the
basionym
In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...
).
"Dog whelk" can also refer to the
Nassariidae
The Nassariidae, Nassa mud snails (USA), or dog whelks (UK), are a taxonomic family of small to medium-sized sea snails, marine gastropod mollusks in the clade Neogastropoda.
"Dog whelk" also refers to ''Nucella lapillus''.
Shell description
T ...
.
Distribution
This species is found around the coasts of Europe and in the northern west
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
coast of North America. It also can be found in
estuarine
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
waters along the
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
coasts. This species prefers rocky shores, where it eats
mussels
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which ...
and
acorn barnacle
Acorn barnacle and acorn shell are Common name, vernacular names for certain types of stalkless barnacles, generally excluding goose barnacles, stalked or gooseneck barnacles. As adults they are typically cone-shaped, symmetrical, and attached to r ...
s.
[Colin Little, J. A. Kitching, 1996]
''The Biology of Rocky Shores''
pp. 140-145.
Shell description
![Nucella Lapillus](https://upload.wikimedia.org/wikipedia/commons/3/39/Nucella_lapillus.jpg)
The dog whelk shell is small and rounded with a pointed
spire
A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...
and a short, straight
siphonal canal
The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...
(a groove on the underside of the shell) and a deep anal canal. The overall shell shape varies quite widely according to the degree of exposure to
wave action
In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. The contact distance in the direction of t ...
of the shore on which a particular population lives but the
body whorl (the largest section of the shell where the majority of the
visceral mass is located) is usually around 3/4 of the total length of the shell. The
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An opt ...
is usually crenulated in mature dog whelks, less often in juveniles.
The shell surface can be fairly smooth interrupted only with growth lines, or when the snail is living in more sheltered areas the shell surface can be somewhat rough and lamellose. The surface is spirally corded. The outer lip is dentate and ridged within. The
columella
Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire.
His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...
is smooth.
The external shell colour is usually a whitish grey, but can be a wide variety of orange, yellow, brown, black, or banded with any combination of these colours. They can even, occasionally, be green, blue, or pink.
Ecology
Habitat
The dog whelk lives on rocky shores, and in estuarine conditions. Climatically it lives between the 0 °C and 20 °C
isotherms.
Effects of the habitat
Wave action tends to confine the dog whelk to more sheltered shores, however, this can be counteracted, both by
adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
s to tolerate it such as the shell and muscular foot, and by the avoidance of direct exposure to wave action afforded by making use of sheltered
microhabitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
s in rocky crevices. The preferred
substrate material of the dog whelk is solid
rock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wales ...
and not
sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...
, which adds to its problems at lower levels on the shore where
weathering
Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...
is likely to have reduced the stability of the
seabed
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
.
Water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
loss by
evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
has to be tolerated (by means of the
operculum which holds water in and prevents its escape as
vapour
In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Herr ...
), or avoided (by moving into water or a shaded area).
The peak in dog whelk
population density
Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopul ...
is approximately coincidental with the mid-
tidal zone
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...
. It lives in the middle shore. In general it can be said that at high vertical heights on the shoreline the dog whelk is most threatened by
biotic factors such as predation from birds and
interspecific competition
Interspecific competition, in ecology, is a form of competition in which individuals of ''different'' species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. ...
for food, but
abiotic
In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them under ...
factors are the primary concern, creating a harsh environment in which it is difficult to survive. At low vertical heights it is biotic factors, such as predation from crabs and
intraspecific competition
Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to r ...
, which cause problems. The upper limit of the range in which the dog whelk is generally found is approximately coincidental with the mean high water
neap tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables c ...
line, and the lower limit of the range is approximately coincidental with the mean low water
neap tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables c ...
line, so that the vast majority of dog whelks are found on the mid-
tidal zone
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...
.
Tidal pool
A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide.
Many tide pool habitats are home to especially adaptable animals that ...
s and comparable microhabitats extend the vertical range of
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
s such as the dog whelk as they provide a more constant environment, but they are prone to increased
salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
because evaporation concentrates dissolved substances. This can create
toxic
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...
conditions for many species.
The dog whelk can only survive out of water for a limited period, as it will gradually become
desiccated
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container.
...
and die if emersed for too long.
Metabolic
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
processes within cells take place in solution, and a decrease in water content makes it impossible for the organism to function properly. In experiments it has been shown that 50% of dog whelks die at 40 °C, and it can be assumed that at temperatures lower than this a smaller proportion will be killed off. Furthermore, the dog whelk has to
excrete
Excretion is a process in which metabolic waste
is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
directly into
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
, as it does not have the adaptation possessed by many upper shore species which would allow it to produce
uric acid
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of ...
for excretion without loss of water. When kept emersed for seven days at a temperature of 18 °C, 100% of dog whelks die, in contrast to many
periwinkle species which can lose even more water than the dog whelk (i.e. more than 37% of their total body mass) but survive as a result of their ability to excrete toxic waste products more efficiently.
Feeding habits
Its
adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
s include a modified
radula
The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...
(a toothed
chitin
Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...
ous structure) to bore holes in the
shells of
prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
, complemented by an
organ on the foot which secretes a shell-softening chemical. When a hole has been formed
paralysing chemicals and
digestive enzymes
Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption into the cells of the body. Digestive enzymes are found in the digestive tracts of anima ...
are secreted inside the shell to break the soft body down into a 'soup' which can be sucked out with the
proboscis
A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...
. The plates of barnacles can be pushed apart with the proboscis, and the entire individual is eaten in about a day, although larger animals such as mussels may take up to a week to
digest.
Feeding only occurs when conditions are conducive to such an activity, and during these times the dog whelk consumes large quantities of food so that the
gut is always kept as full as possible. This allows shelter until more food is required, when
foraging
Foraging is searching for wild food resources. It affects an animal's Fitness (biology), fitness because it plays an important role in an animal's ability to survive and reproduce. Optimal foraging theory, Foraging theory is a branch of behaviora ...
resumes. If
waves
Waves most often refers to:
*Waves, oscillations accompanied by a transfer of energy that travel through space or mass.
* Wind waves, surface waves that occur on the free surface of bodies of water.
Waves may also refer to:
Music
* Waves (ban ...
are large or there is an excessive risk of water loss the dog whelk will remain inactive in sheltered locations for long periods.
Mussels have developed a defensive strategy of tethering and immobilising with byssus threads any dog whelks invading their beds, leading to the whelks' starvation.
Life cycle
Predators
Predators of the dog whelk include various species of
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s and
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s. Protection against
predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
from crabs which attempt to pull the soft body out through the shell
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An opt ...
can be afforded by growing
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
around the edge of the aperture. Many predators cannot smash the strong shell of an adult dog whelk, but
juveniles are vulnerable to attack from many predatory species.
Eider duck
Eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere.
The down feathers of eider ducks, and some other ducks and geese, are used to fill pillows and quil ...
s and various other birds simply swallow the entire body with its shell, while
oystercatchers
The oystercatchers are a group of waders forming the family Haematopodidae, which has a single genus, ''Haematopus''. They are found on coasts worldwide apart from the polar regions and some tropical regions of Africa and South East Asia. The e ...
and various
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s are often capable of crushing or breaking the shells. In the winter they endure more predation from
purple sandpiper
The purple sandpiper (''Calidris maritima'') is a small shorebird in the sandpiper family Scolopacidae. This is a hardy sandpiper that breeds in the arctic and subarctic regions of Eurasia and North America and winters further south on the Atlant ...
s and similar
wading birds
245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
, but in the summer crabs represent a greater threat. In general, the dog whelk can be thought of as being vulnerable to birds when emersed, and to crabs when immersed.
Human use
The dog-whelk can be used to produce red-purple and violet dyes, like its Mediterranean relations the spiny dye-murex
''Bolinus brandaris'', the banded dye-murex ''
Hexaplex trunculus
''Hexaplex trunculus'' (previously known as ''Murex trunculus'', ''Phyllonotus trunculus'', or the banded dye-murex) is a medium-sized sea snail, a marine gastropod mollusk in the family Muricidae, the murex shells or rock snails. It is included ...
'' and the rock-shell ''
Stramonita haemastoma
''Stramonita haemastoma'', common name the red-mouthed rock shell or the Florida dog winkle, is a species of predatory sea snail, a marine gastropod mollusc in the family Muricidae, the rock snails.
Subspecies
''Stramonita haemastoma'' contains ...
'' which provided the
red-purple and violet colours that the Ancient World valued so highly.
Bede
Bede ( ; ang, Bǣda , ; 672/326 May 735), also known as Saint Bede, The Venerable Bede, and Bede the Venerable ( la, Beda Venerabilis), was an English monk at the monastery of St Peter and its companion monastery of St Paul in the Kingdom o ...
mentions that in Britain "whelks are abundant, and a beautiful scarlet dye is extracted from them which remains unfaded by sunshine or rain; indeed, the older the cloth, the more beautiful its colour."
In Ireland, on the island of
Inishkea North, Co. Mayo, archaeologists found a whelk-dyeing workshop, dated to the 7th century AD, complete with a small, presumed vat, and a pile of broken-open dog-whelk shells. Unfortunately, no such workshop is known from Britain for the Early Medieval period. However, a double-checked trace of bromine, indicating the presence of whelk-dye, has been found on one page of an Anglo-Saxon book known as the
Barberini Gospels. This manuscript dates to the late 8th or early 9th century AD, and the whelk dye occurs as a background panel to white lettering at the beginning of St John's gospel. Efforts have also been made to find whelk dye on surviving fragments of Anglo-Saxon textiles, but the chemical analyses so far carried out have proved negative for bromine.
An
Anglo-Saxon
The Anglo-Saxons were a Cultural identity, cultural group who inhabited England in the Early Middle Ages. They traced their origins to settlers who came to Britain from mainland Europe in the 5th century. However, the ethnogenesis of the Anglo- ...
account of the accession ceremony of
Aldfrith of Northumbria
Aldfrith (Early Modern Irish: ''Flann Fína mac Ossu''; Latin: ''Aldfrid'', ''Aldfridus''; died 14 December 704 or 705) was king of Northumbria from 685 until his death. He is described by early writers such as Bede, Alcuin and Stephen of Ripo ...
involved whelk-dyed cloth, although this may simply be a poetic echo of Roman ceremonies. Another example involves an account of valuable textiles brought to England by
Wilfrid
Wilfrid ( – 709 or 710) was an English bishop and saint. Born a Northumbrian noble, he entered religious life as a teenager and studied at Lindisfarne, at Canterbury, in Francia, and at Rome; he returned to Northumbria in about 660, and ...
of Ripon.
References
External links
*
{{DEFAULTSORT:Dog Whelk
Muricidae
Gastropods described in 1758
Taxa named by Carl Linnaeus