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Ixodes ricinus Linnaeus (Acari: Ixodidae) is the most abundant and widely distributed tick in the British Isles, and is a vector for a number of bacterial, viral and protozoal pathogens of both medical and veterinary importance. This report provides an update to the historical distribution data of I. ricinus, published by the Biological Records Centre (BRC), Monks Wood in The Provisional Atlas of the Ticks (Ixodidae) of the British Isles by K. P. Martyn (1988), and is supplemented with additional BRC records since 1988, additional data from published scientific literature and unpublished field studies, and enhanced with spatial and temporal information on tick stages collected and their host associations. Records have been mapped at 10 km resolution and enhanced to 5 km, 1 km and 0.1 km. Differentiation between records representing one-off collections from those representing populations of I. ricinus has been achieved through the classification of the records into either reported or established populations. Detailed seasonality and host associations of records are investigated, highlighting the value in obtaining additional detailed contemporary data to aid risk assessments and research within this field.

The recent implication of Dermacentor reticulatus (Ixodida: Ixodidae) in the transmission of canine babesiosis in the U.K. has highlighted the lack of accurate published data on its distribution in this country. This paper aims to collate and appraise historical data for D. reticulatus, to supplement such data with more recent surveillance data and to report on field sampling conducted during 2009-2016. These updated data facilitate better understanding of the current distribution of this tick in the U.K., which will better inform disease risk assessments. There appear to be four known regions of the U.K. in which D. reticulatus currently occurs, including western Wales, North and South Devon, and Essex. The majority of foci are located in coastal sand dunes and maritime grasslands, including grazing marsh. However, more recently the tick has been detected in urban greenspace in Essex. The emergence of this tick as a vector of babesiosis in the U.K. and its recent apparent spread in Essex into urban greenspace highlight the need for continued surveillance and for further research into its status as a vector of human and veterinary pathogens.

The spatial heterogeneity of questing Ixodes ricinus (L.) (Acari: Ixodidae) within endemic areas in Great Britain is well established. Their presence is acutely responsive to blood host availability and their ability to maintain water balance, which are in turn governed by a variety of ecological and environmental factors. This article details the findings of a 3-yr study on the Gower peninsula, south Wales, which investigated the contribution of such factors (both ground- and geographic information systems [GIS] -derived) for predicting the presence of questing I. ricinus (Q(P)), at a local scale. Statistically significant univariate associations were found between Q(P) and calcareous/ neutral grassland and heathland habitats, particularly those grazed by livestock, and various factors that intuitively promote tick survival. For example, topographical features, such as certain aspects, that reduce exposure to cold northerly winds and the hot midday sun, favored Q(P). Similarly, positive associations were found with substrata composed of less permeable soil types and less permeable superficial/bedrock geologies that promote a moist microhabitat and reduce the likelihood of desiccation. Q(P) was also higher in areas of high soil moisture. This study highlighted a number of GIS-derived data sets that could be applied in the development of local and national predictive maps for I. ricinus in Great Britain. An understanding of the influence of these factors on questing I. ricinus can aid targeted tick control programs and help to educate the public, and those occupationally exposed, in understanding likely I. ricinus prolific areas within an I. ricinus endemic region.