Ixodes ricinus is a geographically widespread species and is Europe’s commonest tick. It has been collected throughout the British Isles. Like all other ticks, Ixodes ricinus is a blood-feeding ectoparasite of vertebrates. Its hosts are mainly small to large mammals, but birds and sometimes reptiles are also parasitized. Egg-laying and moulting occur away from the host, ideally in thick vegetation that maintains a humid atmosphere within it. Infestations can cause a decline in host health due to blood loss. Also tick paralysis, thought to be a result of a neurotoxin introduced during feeding, may occur. However, Ixodes ricinus is most well-known as a vector of diseases, particularly Lyme borreliosis (Lyme disease).

Ixodes ricinus (often known as the Sheep Tick) occurs widely in relatively humid, cool, shrubby and wooded pastures, gardens, windbreaks, floodplains, and forest through much of Europe to the Caspian Sea and northern Iran, as well as in northwestern Africa. Its life cycle requires two to four years, depending on temperature. (In drier, warmer, eastern Mediterranean regions, I. ricinus is replaced by I. gibbosus, which completes its life cycle in just one year.) Ixodes ricinus larvae feed on small reptiles, birds, and mammals. Nymphs feed on small and medium-sized vertebrates and adults feed mainly on mammalian herbivores and livestock. All stages, especially nymphs and adults, parasitize humans. Male I. ricinus take little or no food, but mate on the host while the female feeds. Adult activity peaks in spring; in some populations, there is a lower peak of adult activity in the fall. Among the numerous diseases transmitted by I. ricinus to domestic animals and humans are tickborne encephalitis, Crimean-Congo hemorrhagic fever, ovine encephalomyelitis, Lyme disease, babesia, and anaplasmosis. (Merck Veterinary Manual online)

Ixodes ricinus is well known as an important vector in Europe of Lyme borreliosis (Lyme Disease), the most prevalent tick-transmitted infection not only in this region but, more generally, in temperate areas of Europe, North America, and Asia. (In the eastern United States and western United States, the main Lyme disease vectors are the related ticks I. scapularis and I. pacificus, respectively.)

There is a clear correlation between the increase in the USA and much of western Europe in abundance of deer (the main hosts for adult I. scapularis [in the eastern United States] and I. ricinus [in Europe]) with tick density. This is due to conversion of agricultural land into habitat suitable for the maintenance of large populations of deer. (Jongejan and Uilenberg 2004)

Morphology
Ixodes ricinus is a tick (order Ixodida) because it has:

• backwardly-pointing teeth on the hypostome
• a Haller’s organ on the terminal segment (tarsus) of the front legs -each organ comprises a pit and capsule containing hair-like sensory structures (setae)
• the external respiratory openings (spiracles) are located on a pair of spiracular plates

It is a hard tick (family Ixodidae) because:

• the gnathosoma (the mouthparts) – comprising the hypostome, palps and chelicerae - is large and clearly visible from above in all life stages
• the upper body surface is partly (larva, nymph, female) or completely (male) covered by a hardened shield (scutum)

The anal groove arching in front of the anus is only seen in the genus Ixodes.Adult specific character states are:

• the female scutum is almost circular
• the basal segment (coxa) of the first pair of legs (legs I) has a long, slender internal spur
• all leg coxae have a small external spur
• the tarsi of legs I taper towards their apex
• the female genital aperture is between leg coxae IV

Look-alikes
Ixodes hexagonus Leach – the hedgehog tick - has a similar distribution to I. ricinus and parasitizes many of the same host species. It can be easily identified by the hump near the apex of tarsus I (absent in I. ricinus), the female genital aperture being between coxae III and not IV, and the rounded hexagonal, rather than circular, scutum.

Life cycle
The tick’s life cycle comprises the egg, 6--legged larva, 8--legged nymph and adult (female and male).Ixodes ricinus is a 3-host tick - the larva, nymph and adult female each feeds once on a different host individual, dropping to the ground between each stage. Development from egg to adult can take 1--6 years, depending on the weather and host availability, but usually 2--3 years.Ticks feed mainly from March to June, reaching a height of activity in April-May. Autumn-feeding ticks occur in some regions, peaking in September-October.In winter, the activity of all stages usually ceases.

Reproduction
Mating occurs on or off the host. It often takes place while the female is feeding.The male crawls under the female and transfers a packet of sperm (spermatophore) from his genital orifice to hers using his chelicerae.After feeding, fertilized females oviposit on the ground, laying a total of several thousand eggs.

In Great Britain and/or Ireland:
Animal / vector
Borrelia is spread by Ixodes ricinus
Other: major host/prey

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Homo sapiens

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of between pads of Canis familiaris

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Felis

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Ovis aries

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Bos taurus (domestic)

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of skin of Apodemus sylvaticus

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Dama dama

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Mustela vison

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Rodentia

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Erinaceus europaeus

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Oryctolagus cuniculus

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Suidae

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Cervidae

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Cricetidae

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Lacertidae

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Aves

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Sturnus vulgaris

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Turdus merula

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Erithacus rubecula

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Turdus

Animal / parasite / ectoparasite / blood sucker
nymph of Ixodes ricinus sucks the blood of Corvus corone corone

Animal / parasite / ectoparasite / blood sucker
Ixodes ricinus sucks the blood of Phasianus colchicus
Other: major host/prey

Virus / infection vector
Louping Ill virus is spread by Ixodes ricinus

Animal / vector
redwater disease protozoan is spread by Ixodes ricinus

Distribution
This species of tick can be found through much of the western Palaearctic region:

• Iceland marks its northern and western limits
• the Atlas Mountains over to northern Iran its southern limit
• western Russia marks its eastern limit

Habitat and hosts
Many species of wild and domesticated vertebrates are parasitized, although rarely bats. Humans can also be hosts.Females, nymphs and larvae prefer medium-sized to large mammals such as sheep, cattle, deer and dogs. Nymphs and larvae predominate on small mammals (stoats and smaller), most birds and reptiles.Egg-laying and development between life stages occur off the host. Ticks are prone to desiccation and require habitats with a thick mat of moisture-retaining vegetation and plant litter near the ground.Rough pasture, moorland and heathland are typical tick habitats.

Ticks ‘quest’ for a host at the tip of grass blades etc where they:

• wave their front legs in the direction of an approaching animal and if it brushes by and is suitable, the ticks climb aboard
• host stimuli are detected by setae in Haller’s organ and on the tip of the front legs and palps - different setae are sensitive to, for example, vibrations, carbon dioxide, temperature and humidity

Ticks dehydrate if they fail to find a host. To avoid this, they periodically move back down to the humid vegetation layer to absorb water. Then they ascend to try again. Before a tick feeds, it pierces the skin using the serrated digits of the chelicerae. The toothed hypostome is worked into the wound by rocking motions and it acts as an anchor. Salivary glands secrete a cement round the feeding tube formed by the hypostome and chelicerae. This also fixes the tick to its host. Wound formation damages adjacent tissue and blood capillaries, while salivary secretions are thought to cause haemorrhaging. A blood pool forms as a result. Blood is sucked up the feeding tube in approximately 30 second bursts. After a rest, more salivary secretions are injected into the host’s tissues. Once fully fed (engorged), ticks detach by retracting the chelicerae and loosening the hypostome from the cement by muscular movements of the mouthparts. Larvae feed for 2--6 days, nymphs for 3--8 days, and females for 6—12 days. Females expand enormously during feeding. They increase in length from about 3mm (unfed) to 11mm (engorged). They also change colour from deep yellow to blue-grey. Males feed only briefly, if at all, and there is little size increase. Their length ranges from about 2.2 to 2.8mm.

DiseasesIxodes ricinus is the main vector (transmitter) of species of the Borrelia burgdorferi complex - the spirochaete that causes Lyme borreliosis (Lyme disease). Lyme borreliosis is the commonest tick-borne disease of humans in Europe and North America. The various spirochaete species are associated with different types and severity of symptoms – for example, those that occur in the UK are apparently less virulent than those in North America. The longer a tick feeds, the more opportunity there is for spirochaetes to pass into the host. Therefore, early tick removal can reduce the chances of acquiring the disease. Ticks also transmit other infectious organisms including those of:

• louping-ill (an encephalomyelitis of sheep, cattle and occasionally humans)
• Q-fever (a rickettsial disease of domesticated mammals and humans caused byCoxiella burnetii)
• bovine and ovine tick-borne fever (rickettsial diseases of livestock and, in the first case, humans)
• tularemia or rabbit fever (a bacterial disease of cats, sheep, rabbits, rodents and their predators, and humans)
• tick pyaemia of lambs (caused by the bacterium Staphylococcus aureus)
• redwater fever of cattle (caused by the protozoan Babesia divergens)

Receptors detect ruminant hosts: hard ticks
 

Some hard tick species detect ruminant hosts via olfactory receptor cells for the carboxylic acid, phenol and indole endproducts they expel.

   
  "Hard ticks spend most of their life isolated from passing vertebrates but require a blood meal to proceed to the next life stage (larva, nymph or adult). These opportunist ectoparasites must be capable of anticipating signals that render suitable hosts apparent. Large ungulates that tolerate a high ectoparasite burden are the favoured hosts of adult hard ticks. Ruminants, comprising the majority of ungulate species, must regularly eruct gases from the foregut to relieve excess pressure and maintain a chemical equilibrium. Through eructations from individuals, and particularly herds, ruminants inadvertently signal their presence to hard ticks. Here, we report that all adult hard tick species we tested are attracted to cud and demonstrate that these acarines possess olfactory receptor cells for the carboxylic acid, phenol and indole endproducts of the rumen bioreactor. Compounds from each of these classes of volatiles attract ticks on their own, and mixtures of these volatiles based on rumen composition also attract. Appetence for rumen metabolites represents a fundamental resource-tracking adaptation by hard ticks for large roaming mammals." (Donze et al. 2004:4283)
  Learn more about this functional adaptation.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 14
Species With Barcodes: 1