Eisen L
Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
J Med Entomol. 2007 Mar;44(2):359-66. doi: 10.1603/0022-2585(2007)44[359:spohab]2.0.co;2.
Nonremoval drag sampling was conducted in multiple sites in Larimer County, CO, from March to July 2006 to determine the seasonal pattern of host-seeking activity by the human-biting adult life stage of the Rocky Mountain wood tick, Dermacentor andersoni Stiles (Acari: Ixodidae). Four sites, at elevations ranging from 1,790 to 2,470 m, consistently yielded host-seeking ticks. Ticks were active from March until late June; the length of the active period ranged from 84 to 104 d. Based on site-specific linear regression models of increase and decrease in tick host-seeking activity over time, densities of D. andersoni adults were estimated to reach 50% of their peaks between 2 and 11 April, to peak between 21 and 28 April, and to fall below 50% of the peaks between 24 and 27 May. The length of the periods with tick densities exceeding 50 and 75% of the peak was 43-52 and 21-26 d, respectively. Rapid increases in tick numbers in late March to early April followed a stretch of days with daily maximum temperatures exceeding 5 degrees C, whereas rapidly declining tick numbers in mid- to late May were associated with daily maximum temperatures consistently exceeding 20 degrees C and daily minimum relative humidity commonly falling below 20%. Densities of D. andersoni adults exceeded 50% of the peak when daily maximum temperatures were in the 16-19 degrees C range and daily minimum relative humidity was > 20%. Finally, tick seasonality may be adapted to local climatic conditions within Larimer County; site-specific daily maximum temperatures at the time of peak tick host-seeking activity in late April were positively associated with site-specific mean daily maximum temperatures for April.
2006年3月至7月，在科罗拉多州拉里默县的多个地点进行了非移除式拖网采样，以确定落基山木蜱（Dermacentor andersoni Stiles，蜱螨目：硬蜱科）成蜱叮咬人类阶段寻找宿主活动的季节性模式。四个海拔在1790至2470米之间的地点持续捕获到寻找宿主的蜱。蜱的活动时间为3月至6月下旬；活动期长度为84至104天。根据特定地点的蜱寻找宿主活动随时间增减的线性回归模型，估计安德逊革蜱成虫密度在4月2日至11日之间达到峰值的50%，在4月21日至28日之间达到峰值，并在5月24日至27日之间降至峰值的50%以下。蜱密度超过峰值50%和75%的时间段长度分别为43 - 52天和21 - 26天。3月下旬至4月初蜱数量的快速增加之前是一段日最高气温超过5摄氏度的日子，而5月中旬至下旬蜱数量的迅速下降与日最高气温持续超过20摄氏度以及日最低相对湿度通常低于20%有关。当日最高气温在16 - 19摄氏度范围内且日最低相对湿度>20%时，安德逊革蜱成虫密度超过峰值的50%。最后，蜱的季节性可能适应拉里默县的当地气候条件；4月下旬蜱寻找宿主活动高峰期的特定地点日最高气温与4月的特定地点日最高平均气温呈正相关。
