Castor Bean Tick

• It has a cycle involving three different hosts that takes two to three years to complete, and can stretch to six in extreme cases.
• As many as 160 vertebrate species have been documented as its hosts: larvae and nymphs feed on rodents, birds and lizards, and the adults on large mammals.
• The nymph, barely 1-2 mm across, is the main transmitter of Lyme borreliosis to people precisely because it goes unnoticed; it needs more than 24 hours of contact to pass the infection on.
• It is the main vector of Lyme disease in Europe, caused by bacteria of the Borrelia burgdorferi complex, and it also transmits tick-borne encephalitis and several babesioses and anaplasmoses.
• It hunts by waiting: it climbs the vegetation, stretches out its first pair of legs and waits motionless, sometimes for weeks, until an animal brushes the grass. That posture is called questing.
• It locates its host by carbon dioxide, heat, humidity and vibrations, using a sensory organ on its front legs called Haller's organ.
• Its saliva is a pharmacological cocktail: it contains anaesthetics, anticoagulants, vasodilators and immunosuppressants, which is why its bite goes unnoticed and it can feed for days.
• The risk of Borrelia transmission grows with attachment time: removing the tick within the first 24 hours greatly reduces the chance of infection, which is why checking yourself after a walk in the countryside is the most effective preventive measure.
• It should be removed by pulling perpendicular to the skin with fine tweezers and without twisting it — no oil, alcohol or heat, which make it regurgitate and increase the risk.
• Its life cycle lasts up to three years and passes through three different hosts, normally a rodent, a bird or lizard, and a large mammal.

Skeleton type

Invertebrate - chitin exoskeleton (arachnid)

Habitat & environment

Damp, cool country with shrubs and trees, heathland, gardens, floodplains and woodland. In Spain its main stronghold is the north of the peninsula: Galicia, Asturias, Cantabria and the Basque Country. Absent from much of the Mediterranean region, where the dry summers rule it out

Sources consulted: Estrada-Peña et al. 2017, Ticks of Europe and North Africa (Springer); Otranto, Dantas-Torres y Santos-Silva 2017; IREC-CSIC (Peralbo Moreno et al.); Boletín Epidemiológico Semanal del Centro Nacional de Epidemiología (ISCIII); Díaz et al. 2017, Parasites & Vectors 10; Manual Veterinario MSD

Best time: From March to October, peaking in April-June with a second rise in September-October