Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA; Department of Biology, Mount St. Joseph University, Cincinnati, OH, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Jul;257:110939. doi: 10.1016/j.cbpa.2021.110939. Epub 2021 Mar 29.
Temperature limits the geographic ranges of several tick species. Little is known about the thermal characteristics of these pests outside of a few studies on survival related to thermal tolerance. In this study, thermal tolerance limits, thermal preference, and the impact of temperature on activity levels and metabolic rate were examined in larvae for six species of ixodid ticks. Tolerance of low temperatures ranged from -15 to -24 °C with Dermacentor andersoni surviving the lowest temperatures. High temperature survival ranged from 41 to 47 °C, with Rhipicephalus sanguineus sensu lato having the highest upper lethal limit. Ixodes scapularis showed the lowest survival at both low and high temperatures. Thermal preference temperatures were tested from 0 to 41 °C. The majority of species preferred temperatures between 17 and 22 °C, while Dermacentor variabilis preferred significantly lower temperatures, near 12 °C. Overall activity was measured across a range of temperatures from 10 to 60 °C, and most tick species had the greatest activity near 30 °C. Metabolic rate was the greatest between 30 and 40 °C for all tick species and was relatively stable from 5 to 20 °C. The optimal temperature for tick larvae is likely near the thermal preference for each species, where oxygen consumption is low and activity occurs that will balance questing and conservation of nutrient reserves. In summary, tick species vary greatly in their thermal characteristics, and our results will be critical to predict distribution of these ectoparasites with changing climates.
温度限制了几种蜱虫物种的地理分布范围。除了少数与热耐受有关的生存研究外，人们对这些害虫的热特性知之甚少。在这项研究中，研究了六种硬蜱幼虫的耐温极限、热偏好以及温度对活动水平和代谢率的影响。耐低温范围从-15°C 到-24°C，其中草原革蜱的耐低温能力最强。高温存活范围从 41°C 到 47°C，其中钝缘蜱亚种的最高上限温度最高。在低温和高温下，肩突硬蜱的存活率最低。热偏好温度测试范围从 0°C 到 41°C。大多数物种更喜欢 17°C 到 22°C 的温度，而草原革蜱则更喜欢明显更低的温度，接近 12°C。在 10°C 到 60°C 的温度范围内测量了总体活动，大多数蜱种在接近 30°C 时活动最多。所有蜱种的代谢率在 30°C 到 40°C 之间最高，在 5°C 到 20°C 之间相对稳定。蜱幼虫的最佳温度可能接近每个物种的热偏好，在这个温度下，氧气消耗最低，并且发生的活动可以平衡寻找和营养储备的保存。总之，蜱种在热特性方面差异很大，我们的研究结果对于预测这些外寄生虫在气候变化下的分布至关重要。
