Hibernation of Hyalomma savignyi (Ixodidae) in Palestine

Galuzo (1941) in his ecological studies of the tick fauna in Kazakh S.S.R. states that the nymph of Hyalomma detritum, Schulze, overwinters on the host, that he is of the opinion that H. savignyi, Gerv., hibernates in the adult stage away from the host (in animal quarters or houses) and that he found hibernating nymphs of H. marginatum, Koch, in grass meadows.

In the course of field work carried out in Palestine during the winter 1945–16 only a few adult male and female ticks (some gorged) were found in the Jordan Valley and the Negeb, and none in the more temperate parts of the country.

An arsenic-resistant tick and its control with gammexane dips

The rapid spread of the single host arsenic-resistant blue tick, B. decoloratus, a transmitter of piroplasmosis and anaplasmosis, seriously affected a large and important cattle ranching area in South Africa.

Biological tests, using the laboratory technique described in an earlier paper, enabled the most effective “Gammexane” preparations to be rapidly selected from numbers of experimental dips. The technique was also employed as a supplement to chemical analyses of dip wash samples where only the total hexachlorocyclohexane and not gamma isomer was estimated. Twenty-thousand adult female ticks were used in these in vitro tests. Oil emulsions seemed more active than dispersible powders or pastes, but all tests indicated that 50 parts per million “Gammexane” should satisfactorily control the tick in the field.

Laboratory tests with larvae of the blue tick showed that “Gammexane” had a persistent action and was very toxic to this stage of the tick. Excellent control of larval ticks could be anticipated in the field.

In vitro tests indicated that “Gammexane” was effective against the two- and three-host ticks, R. evertsi, R. appendiculatus, A. hebraeum, H. silacea and Hyalomma spp., but hand dressing and shorter dipping intervals might be necessary to control these ticks in the field. The sheep paralysis tick, I. pilosus, seemed to be resistant to “Gammexane” but was readily killed by arsenic.

Some aspects of the ecology of the tick, Ixodes ricinus, L., in Wales

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.