Some Aspects of the Ecology of the Tick, Ixodes ricinus, L., in Wales

Abstract

The results presented in this paper apply to conditions in Wales. Although admittedly based on limited data, they show that of the nine species of ticks found in the Principality, only Ixodes ricinus, L. is found on sheep, cattle and horses.It has been observed that the distribution of ticks throughout Wales is influenced by superficial soil deposits: studies in north, central and south Wales have shown, however, that the vegetation index from which ticks are recovered is variable. Analysis of soils from which ticks are recovered, gave a pH range of from 4·4 to 5·2, and the relationship between “mat” and soil acidity is discussed.An investigation of four adjoining tracts of vegetationally different land—rush, bracken, heather-winberry and ley—showed that greater populations and a greater rate of activity were apparent in rush land. The significance of topographical location in relation to tick infestation even on land with the same vegetation index is indicated. A salt marsh adjoining an infested non-salt marsh was found to be free of ticks.The occurrence of a unimodal activity curve is described for central and north Wales. Within a recognized bimodal activity belt irregularities of tick periodicity on cattle have been observed at some farms. This appears to be related to the nature of the sward, and, where good pasture occurs alongside “islands” of damp ground, such discrepancies are noted.Such “islands” may harbour ticks, while the rest of the pasture is free. When, as the result of certain influences, cattle move to these “islands” they become infested. A meteorological condition is described which leads indirectly to such movement through the agency of the warble fly.