The biological processes affecting Ixodes scapularis Say survival are complex. Understanding these processes will be beneÞcial for predicting tick distribution and population dynamics. This research shows that the duration for which nymphal ticks are exposed to drying air is an important factor for their survival. Experimental analysis of variance results show that duration of exposure to dry air (duration) is as important as vapor pressure deÞcit (relative humidity) (duration, relative

more »

... , P Ͻ 0.0001). Ticks do not survive when exposed to dry air for long periods; however, the return of humid air within 4 Ð 8 h has as large a positive impact on tick survival, as does constant humid air. This experiment exposes nymphal ticks to conditions of suboptimal humidity for different durations and then returns them to saturated conditions that are more typical of daily relative humidity ßuctuations experienced during summer in southern New England forests.