The black-legged tick, Ixodes scapularis (Ixodida, Ixodidae), is one of the major disease vectors in the United States and due to multiple human impact factors, such as decreasing forest size for land development and climate change, it has expanded its range and established across the United States. Throughout the life cycle, ticks locate hosts for their blood-meal and although the ecologies of this tick and their hosts have been studied in depth, the sensory physiology behind host location largely remains unexplored. Here we report establishing a robust paradigm to isolate and identify odors from the natural milieu for I. scapularis. We performed single sensillum recordings (SSR) from the olfactory sensilla on the tick tarsi, and used the SSR system as biological detector to isolate natural compounds that elicited biological activity. The SSR setup was further tested in tandem with gas chromatography (GC) wherein the ticks olfactory sensillum activity served as a biological detector. The GC-SSR recordings from the wall pore sensilla in the Hallers organ, and further identification of the biologically active deer glad constituents by GC-mass spectrometry (GC-MS) revealed methyl substituted phenols as strong chemostimuli, as compared to ethyl or propyl substitutions. Strongest electrophysiological activity was elicited by meta-cresol followed by para-cresol. Ethyl- and propylphenols with any of the three, ortho, meta or para substitutions, did not induce any neurophysiological activity. Finally, a behavioral analysis in a dual-choice olfactometer of all these phenols at three different doses revealed no significant behavioral response, except for p- cresol at -3 dilution Overall, this study contributes to our understanding of I. scapularis ticks neurophysiology and provides a robust platform to isolate and identify natural attractants and repellents.

中文翻译：

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肩x骨对宿主气味的神经生理和行为反应

黑脚tick（Ixodes scapularis）（Ixodida，Ixodidae）是美国的主要疾病媒介之一，由于多种人类影响因素，例如为土地开发和气候变化而减少的森林面积，它扩大了范围并在美国各地建立。在整个生命周期中，s虫都在寻找宿主的血粉，尽管对tick虫及其宿主的生态学进行了深入研究，但宿主位置背后的感觉生理学仍未得到开发。在这里，我们报告建立一个健壮的范例，以从肩I鱼的自然环境中分离和识别气味。我们从the蛇的嗅觉感官上进行了单感官录音（SSR），并使用SSR系统作为生物检测器来分离引发生物活性的天然化合物。SSR设置进一步与气相色谱法（GC）串联测试，其中tick嗅嗅觉活性用作生物检测器。来自Hallers器官壁孔感觉器的GC-SSR记录，以及通过GC-质谱（GC-MS）进一步鉴定具有生物活性的鹿角成分，发现与乙基或丙基取代相比，甲基取代的苯酚具有很强的化学计量比。 。间甲酚，对甲酚引发了最强的电生理活性。具有三个邻位，间位或对位取代中的任何一个的乙基和丙基苯酚均不会诱导任何神经生理活性。最后，在双选择嗅觉仪上对所有这些苯酚在三种不同剂量下的行为分析表明，除了在-3稀释下的对甲酚外，没有明显的行为反应。