The ecology of the sheep tick,Ixodes ricinusL. Host relationships of the tick: Part 1. Review of previous work in Britain

Abstract

On the whole published data on the host relationships of Ixodes ricinus L. in Britain are rather inadequate, but the following points emerge:The tick (stages unspecified) has been found on twenty-three mammal, twenty-one bird and one reptile species. These include both wild and domestic animals. There are no records of non-hosts. The host list is incomplete. Its length and variety suggest, however, that the tick will feed on practically any mammal or bird it may meet.Tick stages found on fifteen mammal, twenty-one bird and one reptile species have been recorded. For a number of reasons (see text) ‘recorded’ absence of any tick stage from an animal is not necessarily reliable. This, together with the incompleteness of the host list, detracts a little from the assertion of several authors, namely, that in general larvae and nymphs occur on both mammals and birds, but adult ticks on mammals only.No precise host-potentials for any wild species relative to sheep (or other important farm stock) have been published in Britain. But, in one area, Scottish mountain hare, red deer and roe deer have been slaughtered on a large scale because of their alleged importance as hosts. Very inadequate data from two authors seem to suggest that as normally stocked populations (a) grouse are negligible compared with sheep as hosts to female ticks, and (b) mountain hare and red deer may play quite an important part in maintaining female ticks. Suggestion (b) at least should not be taken seriously until comprehensively investigated.One author shows that an ‘appreciable’ tick population was maintained on a hill grazing by a reduced wild fauna in the absence of sheep.Another author shows that the tick population of a grazing was considerably reduced by acaricidal treatment of sheep, together with almost complete extermination of a section of the wild fauna. Unfortunately, the two factors cannot be disentangled.We would like to thank Mr Charles Elton, Director, Bureau of Animal Population, Oxford, and Dr J. MacLeod of the Cooper Technical Bureau, Berkhamsted, for criticism of the MS.; Mr F. Wallace for information on red deer stocking; and Dr V. B. Wigglesworth, F.R.S.,. Director, Agricultural Research Council Unit of Insect Physiology, Cambridge, within whose organization the work was done.

Effects of global changes on the climatic niche of the tick Ixodes ricinus inferred by species distribution modelling

“…With respect to biotic factors, the hosts are key components for the ecological niche of ticks [7,63,64]. Ixodes ricinus is able to exploit a large variety of terrestrial vertebrates [7,63-65], so that host occurrence should not be a limiting factor to their persistence under climatic change scenarios [66]. Its wide ecological plasticity with respect to host choice, for example, was a key factor in allowing I. ricinus to survive during the last glacial phases without significant range reduction across the European continent [67].…”

“…Host movements largely determine tick dispersal during infestation [65,68-72]. Among the several hosts exploited by I. ricinus, some of them, such as birds and cervids, are characterized by high dispersal ability.…”

Tracing the origins of louping ill virus by molecular phylogenetic analysis.

“…However, this cannot account for the movement of LI virus and infected ticks over large distances to isolated habitats, for example across the Irish Sea. Infestation of several bird species by I. ricinus has been reported and bird migration may result in the transportation of infected ticks into new areas (Milne, 1949). The third possible mode of LI virus dispersal involves the movement of livestock.…”

Distribution of Ixodes ricinus in the British Isles: investigation of historical records

“…The principal hosts on which I. ricinus are commonly found can vary according to the habitat in which it exists. In upland regions of Great Britain, for example, sheep support more than 90% of the tick population, including the immature stages (Milne, 1949; Ogden et al ., 1997), whereas in woodland habitats, deer, pheasants, rodents and squirrels are the principal hosts (Randolph & Craine, 1995). In Ireland I. ricinus abundance in heterogeneous woodlands is directly related to the presence of deer (supporting both nymphs and adults) and small rodents (supporting larvae) (Gray et al ., 1999), whereas other studies at different locations in Great Britain have revealed negative correlations between deer density and tick abundance (Walker et al ., 2001).…”