The Relation of Rabbit Tick Populations to Spacing in Host Populations

Abstract

An analysis was made of the relation of populations of the bird and rabbit tick, Haemaphysalis leporispalustris to observed spacing between hosts, Sylvilagus floridanus, which were live-trapped, marked, released and retrapped over a period of 3 years. Centers of activity of each rabbit were calculated by the method recommended by Hayne (1949), and distance between centers by a modification of the method recommended by Dice (1952). The average distance between rabbits was measured from each center of observed activity to next nearest center in each of four quadrants except where, as at the margin of the study area, no observations were available. In the latter case the nearest unused distance in any quadrant was substituted. The relatively large number of ticks oh rabbits in dense populations and the relatively smaller numbers on members of sparse populations, usually in narrow or small habitats, are believed to be related mostly to distance between hosts, particularly the rabbits. Ground-inhabiting birds, which also support the larval and nymphal ticks, probably tend to keep the tick populations equalized (by carrying them from habitat to habitat) but these hosts tend to select the same habitats as the rabbits, being most numerous in habitats where rabbits are common. The smaller tick populations on hosts in narrow or small habitats also may be the result of decimation of the non-parasitic stages, lost when the rabbits (or birds) spend time away from fence lines or suitable cover, in cultivated fields or other habitats not suitable to the ticks.