SG: Abiotic constraints on the invasion of ticks and tick-borne pathogens across environmental gradients in Maine

近几十年来，许多具有医学和兽医学意义的硬体蜱物种已急剧蔓延到北方纬度地区。这种扩张增加了传染病对人类、伴侣动物和野生动物的传播。了解环境条件，限制建立和维护蜱虫种群在其北方范围的限制，可能会提高我们的能力，预测未来的范围扩展。此外，更好地了解蜱虫分布将有助于将病媒管理战略针对蜱虫最易受感染的生命阶段和一年中的时间。该项目的目标是确定特定的生物学机制，通过这些机制，非生物因素限制了北美重要疾病媒介黑脚蜱目前北方的地理分布。缅因州是蜱传疾病传播的新兴地区，该地区的强烈气候梯度将用于了解温度和降水对黑腿蜱冬季生存和季节性宿主寻找活动的影响。此外，蜱的范围扩大和三个蜱传病原体的传播之间的关系将进行检查。该项目将为众多本科生和研究生提供培训机会，特别是那些属于传统上在STEM中代表性不足的群体的学生。此外，研究人员将组织公众宣传，重点是安全和有效的个人蜱虫保护措施。该项目将整合操作性现场实验和观察性现场研究，以测试有关黑脚蜱活动范围扩展的环境限制的几个假设，以及范围扩展对蜱传播病原体分布的影响。特别是，研究人员将研究大规模的环境梯度，以更好地了解：1）温度和积雪对黑腿蜱越冬生存的相互作用，2）气候对蜱虫宿主寻找物候的影响，以及3）黑腿蜱及其传播的三种病原体的共同入侵动态。这些目标将通过在缅因州的五个现场建立实验性蜱虫越冬生存测定和宿主寻找行为测定来解决，这些现场代表了一系列温度和降雪条件。此外，将在相同地点对相同地点的非宿主蜱和宿主蜱进行观察性研究。在这项研究工作中使用的操作性实地实验和观察性实地研究相结合，将同时隔离对黑脚蜱目前地理分布的非生物限制，同时保留自然条件的生态现实主义。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In recent decades, numerous hard-bodied tick species of medical and veterinary significance have spread dramatically beyond their historical ranges into more northern latitudes. This expansion has increased transmission of infectious diseases to humans, companion animals, and wildlife. Understanding the environmental conditions that constrain establishment and maintenance of tick populations at their northern range limits may enhance our ability to predict future range expansion. Further, better understanding of tick distribution will facilitate targeting vector management strategies to life-stages and times of year when ticks are most vulnerable. The goal of this project is to identify specific biological mechanisms by which abiotic factors limit the current northern geographic distribution of the blacklegged tick, an important disease vector in North America. A strong climate gradient in Maine, an emerging area of tick-borne disease transmission, will be used to understand the effects of temperature and precipitation on winter survival and seasonal host-seeking activity in the black-legged tick. In addition, the relationship between tick range expansion and spread of three tick-bourne pathogens will be examined. This project will provide training opportunities for numerous undergraduate and graduate students, particularly those belonging to groups traditionally underrepresented in STEM. Also, the researchers will organize public outreach focused on safe and effective personal tick protection practices.The project will integrate manipulative field experiments and observational field studies to test several hypotheses regarding environmental constraints on range expansion of the blacklegged tick, as well as implications of range expansion on the distribution of tick-borne pathogens. In particular, researchers will examine large-scale environmental gradients to better understand: 1) interacting effects of temperature and snow cover on blacklegged tick overwinter survival, 2) impacts of climate on tick host-seeking phenology, and 3) co-invasion dynamics of the blacklegged tick and three pathogens it transmits. These objectives will be addressed by establishing experimental tick overwinter survival assays and host-seeking behavioral assays at five field sites in Maine representing spanning a range of temperature and snowfall conditions. In addition, observational studies of off-host and on-host ticks in the same locations will be conducted at the same locations. The combination of manipulative field experiments and observational field studies utilized in this research effort will simultaneously isolate abiotic constraints on the current geographic distribution of the blacklegged tick while preserving the ecological realism of natural conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.