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

近几十年来，大量具有医学和兽医意义的硬体硬这种扩张增加了传染病对人类、同伴动物和野生动物的传播。了解环境条件可能会增强我们预测未来活动范围扩大的能力，这些环境条件限制了硬蜱种群在北方活动范围的建立和维持。此外，更好地了解蜱虫的分布将有助于将媒介管理策略定向到生命阶段和一年中最脆弱的时间。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的疾病媒介--黑腿扁虱目前在北方的地理分布。缅因州是硬蜱传播疾病的新兴地区，该州的强烈气候梯度将被用来了解温度和降水对黑腿硬蜱冬季生存和季节性寻找宿主活动的影响。此外，还将研究三种壁虱病原体的传播范围扩大和传播之间的关系。该项目将为许多本科生和研究生提供培训机会，特别是那些在STEM中传统上代表人数较少的学生。此外，研究人员将组织公众推广活动，重点关注安全和有效的个人扁虱保护做法。该项目将整合操纵性现场实验和观察性现场研究，以测试几个假设，这些假设涉及环境限制对黑腿壁虱范围扩大的限制，以及范围扩大对壁虱传播病原体分布的影响。特别是，研究人员将研究大尺度的环境梯度，以更好地了解：1)温度和积雪覆盖对黑腿硬蜱越冬生存的交互影响，2)气候对硬蜱寻找寄主物候的影响，以及3)黑腿硬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代表一系列温度和降雪条件的五个野外地点建立实验性扁虱越冬生存分析和寻找宿主的行为分析来实现。此外，还将在同一地点对寄主外和寄主内的扁虱进行观测研究。在这项研究工作中使用的操纵性现场实验和观察性现场研究的结合将同时隔离对当前黑腿壁虱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。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.