Abstract:
We compiled information on the distribution of ticks in the western Palearctic
(11 W, 45 E; 29 N, 71 N), published during 1970–2010. The literature search was filtered
by the tick’s species name and an unambiguous reference to the point of capture. Records
from some curated collections were included. We focused on tick species of importance to human and animal health, in particular: Ixodes ricinus, Dermacentor marginatus,
D. reticulatus, Haemaphysalis punctata, H. sulcata, Hyalomma marginatum, Hy. lusitanicum,
Rhipicephalus annulatus, R. bursa, and the R. sanguineus group. A few records of
other species (I. canisuga, I. hexagonus, Hy. impeltatum, Hy. anatolicum, Hy. excavatum,
Hy. scupense) were also included. A total of 10,280 records was included in the data set.
Almost 42 % of published references are not adequately referenced (and not included in
the data set), host is reported for only 61 % of records and a reference to time of collection
is missed for 84 % of published records. Ixodes ricinus accounted for 44.3 % of total
records, with H. marginatum and D. marginatus accounting for 7.1 and 8.1 % of records,
respectively. The lack of homogeneity of the references and potential pitfalls in the
compilation were addressed to create a digital data set of the records of the ticks. We
attached to every record a coherent set of quantitative descriptors for the site of reporting,
namely gridded interpolated monthly climate and remotely sensed data on vegetation
(NDVI). We also attached categorical descriptors of the habitat: a standard classification of
land biomes and an ad hoc classification of the target territory from remotely sensed
temperature and NDVI data. A descriptive analysis of the data revealed that a principal
components reduction of the environmental (temperature and NDVI) variables described
the distribution of the species in the target territory. However, categorical descriptors of the
habitat were less effective. We stressed the importance of building reliable collections of
ticks with specific references as to collection point, host and date of capture. The data set is
freely downloadable.
