''Ixodes ricinus'', the castor bean tick, is a chiefly

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

an species of hard-bodied

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living ...

. It may reach a length of when engorged with a blood meal, and can transmit both bacterial and viral

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a g ...

s such as the causative agents of

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the '' Borrelia'' bacterium, which is spread by ticks in the genus '' Ixodes''. The most common sign of infection is an expanding red rash, known as erythema ...

and

tick-borne encephalitis Tick-borne encephalitis (TBE) is a viral infectious disease involving the central nervous system. The disease most often manifests as meningitis, encephalitis or meningoencephalitis. Myelitis and spinal paralysis also occurs. In about one third ...

Description

In common with other species of '' Ixodes'', ''I. ricinus'' has no eyes and is not ornate; it has no festoons (wrinkles along the posterior margin). The palpi are longer than they are wide, and an anal groove is above the

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, ...

. It has a hard dorsal shield which covers the entire

opisthosoma The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma (cephalothorax). It is a distinctive feature of the subphylum Chelicerata (arachnids, horseshoe crabs and others). Although it is similar in most respects to ...

(abdomen), but only part of it in females and nymphs. ''I. ricinus'' is the largest of the three common species of ''Ixodes'' in the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isl ...

(the other two being '' I. canisuga'', the British dog tick, and '' I. trianguliceps'', the vole tick). Adult males are long, and unfed nymphs are long; females are long before feeding and long when engorged.

Distribution

''Ixodes ricinus'' is found across

and into neighbouring parts of

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

and the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...

, extending as far north as

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...

and as far east as parts of

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

. Its northern limit seems to be determined by

environmental A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scal ...

factors, including

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

, since a series of mild winters in

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and S ...

coincided with an expansion northwards in the range of ''I. ricinus''. ''I. ricinus'' is most frequent in habitats where its hosts are plentiful, including

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

heaths A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...

and

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s. It is most prevalent in relatively humid areas, and is absent from much of the Mediterranean Region where summers are dry.

Lifecycle

''Ixodes ricinus'' has a three-host

lifecycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring *Life-cycle hypothesis, ...

, which usually takes 2–3 years to complete, although it can take from 1 to 6 years in extreme cases. Adults feed on large mammals such as

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticate ...

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...

, dogs,

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s, and

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

s for 6–13 days, before dropping off. An engorged female lays several thousand eggs and subsequently dies. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e that hatch do not actively seek a host, and usually feed on insectivores (order Eulipotyphla), although they may also find

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit sp ...

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 lightweig ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...

s, or bats. They feed for 3–5 days before dropping off and

moulting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

. The resulting nymphs then ascend

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

es or twigs to seek their next host, but must return to the moist

microclimate A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few squ ...

at the soil surface if they become dehydrated. The nymphs feed on small to medium-sized mammals.

Disease transmission

A number of tick-borne diseases can be transmitted by ''I. ricinus'' to a variety of

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

hosts. Dogs can be infected with

(borreliosis), caused by the spirochaete

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

'' Borrelia burgdorferi'', '' B. afzelii'', and '' B. garinii''. Cattle can become infected with redwater fever (from the protozoans '' Babesia divergens'', '' B. bovis'', and ''B. ovis''), Lyme disease (from ''B. burgdorferi''), sheep tick pyemia (''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

''), cattle tick-borne fever ('' Anaplasma phagocytophila''), Q fever ('' Coxiella burnetii''),

Boutonneuse fever Boutonneuse fever (also called, Mediterranean spotted fever, ''fièvre boutonneuse'', Kenya tick typhus, Indian tick typhus, Marseilles fever, or Astrakhan fever) is a fever as a result of a rickettsial infection caused by the bacterium ''Rickettsi ...

('' Rickettsia conorii''), and the bacterium ''Anaplasma marginale''.

Horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

s may be infected with Lyme disease, ''Anaplasma phagocytophila'', and the viral infection louping ill. Humans can become infected with Lyme disease, louping ill, Q fever, and

, and possibly sensitised to mammalian red meat, known as

alpha-gal allergy Alpha-gal allergy — or mammalian meat allergy (MMA) — is a type of meat allergy characterized by a delayed onset of symptoms (3–8 hours) after ingesting mammalian meat and resulting from past exposure to tick bites. It was first reported in ...

Natural enemies

The parasitic wasp ''

Ixodiphagus hookeri ''Ixodiphagus hookeri'', the tick wasp, is an encyrtid wasp which lays its eggs into ticks. It seems to use a symbiotic bacteria, ''Wolbachia pipientis'', to weaken the tick's immune system. Description ''Ixodiphagus hookeri'' is a small wasp ...

'' lays its eggs inside castor bean ticks, though the castor bean tick is not ''I. hookeris sole host.

Taxonomic history

The

scientific name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

of the castor bean tick dates back to the starting point of zoological nomenclature, the 1758 tenth edition of

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, ...

' ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial ...

'', where it appeared as ''Acarus ricinus''.

Pierre André Latreille Pierre André Latreille (; 29 November 1762 – 6 February 1833) was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom ...

split the new genus '' Ixodes'' from Linnaeus' ''

Acarus ''Acarus'' is a genus of mites in the family Acaridae. Species * '' Acarus ananas'' (Tryon, 1898) * '' Acarus beschkovi'' (Mitov, 1994) * '' Acarus bomiensis'' Wang, 1982 * '' Acarus calcarabellus'' (Griffiths, 1965) * '' Acarus chaetoxysilos'' ...

'' (which at that time contained all known ticks and

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

s), and ''I. ricinus'' was chosen as the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

. It has subsequently been redescribed under a number of

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linn ...

s and subsequent combinations into different genera; these synonyms include ''Acarus ricinoides'', ''Cynorhaestes reduvius'', ''Cynorhaestes ricinus'', ''Ixodes megathyreus'', ''Ixodes bipunctatus'', ''Cynorhaestes hermanni'', ''Crotonus ricinus'', ''Ixodes trabeatus'', ''Ixodes plumbeus'', ''Ixodes reduvius'', ''Ixodes pustularum'', ''Ixodes fodiens'', ''Ixodes rufus'', ''Ixodes sulcatus'' and ''Ixodes sciuri''.

References

External links

* {{Taxonbar, from=Q21175 ricinus Arachnids of Europe Animals described in 1758 Taxa named by Carl Linnaeus