HOST PREFERENCES AND TEMPORAL TRENDS OF THE TICK IXODES ANGUSTUS IN NORTH-CENTRAL ALBERTA

We examined host preferences and temporal trends of the tick Ixodes an gustus on small mammals in north-central Alberta. Small mammals were l ive-trapped from 1 June to 29 September 1994 and 3 May to 30 June 1995 in mature aspen (Populus tremuloides) forest near Lac La Biche, Alber ta. Abundance of female I. angustus was high in early May (0.90 +/- 0. 20 [SE]) and peaked again in late June (0.58 +/- 0.16), whereas abunda nce of immature I. angustus peaked (1.2 +/- 0.35) in mid-July. Red-bac ked voles (Clethrionomys gapperi) and deer mice (Peromyscus maniculatu s) were the most common host species encountered, and tick abundance ( number of ticks per animal examined) on these hosts was strongly influ enced by species and sex. Clethrionomys gapperi had higher rick abunda nce (0.73 +/- 0.07) than did P. maniculatus (0.04 +/- 0.01), and ticks were more abundant on large male C. gapperi (0.97 +/- 0.14) than they were on large female C. gapperi (0.36 +/- 0.08; P = 0.0007). Characte ristics of each species and sex of host in relation to susceptibility to parasitism are discussed.