Campetella Florencia, Ignell Rickard, Beutel Rolf, Hansson Bill S, Sachse Silke
Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany.
Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
PLoS Negl Trop Dis. 2021 Apr 15;15(4):e0009098. doi: 10.1371/journal.pntd.0009098. eCollection 2021 Apr.
American trypanosomiasis, or Chagas disease, is transmitted by both domestic and sylvatic species of Triatominae which use sensory cues to locate their vertebrate hosts. Among them, odorants have been shown to play a key role. Previous work revealed morphological differences in the sensory apparatus of different species of Triatomines, but to date a comparative functional study of the olfactory system is lacking. After examining the antennal sensilla with scanning electronic microscopy (SEM), we compared olfactory responses of Rhodnius prolixus and the sylvatic Rhodnius brethesi using an electrophysiological approach. In electroantennogram (EAG) recordings, we first showed that the antenna of R. prolixus is highly responsive to carboxylic acids, compounds found in their habitat and the headspace of their vertebrate hosts. We then compared responses from olfactory sensory neurons (OSNs) housed in the grooved peg sensilla of both species, as these are tuned to these compounds using single-sensillum recordings (SSRs). In R. prolixus, the SSR responses revealed a narrower tuning breath than its sylvatic sibling, with the latter showing responses to a broader range of chemical classes. Additionally, we observed significant differences between these two species in their response to particular volatiles, such as amyl acetate and butyryl chloride. In summary, the closely related, but ecologically differentiated R. prolixus and R. brethesi display distinct differences in their olfactory functions. Considering the ongoing rapid destruction of the natural habitat of sylvatic species and the likely shift towards environments shaped by humans, we expect that our results will contribute to the design of efficient vector control strategies in the future.
美洲锥虫病，即恰加斯病，由家栖和野生锥蝽传播，锥蝽利用感官线索来定位其脊椎动物宿主。其中，气味物质已被证明起着关键作用。先前的研究揭示了不同种类锥蝽感觉器官的形态差异，但迄今为止，尚未有对嗅觉系统的比较功能研究。在用扫描电子显微镜（SEM）检查触角感器后，我们采用电生理方法比较了克氏锥蝽和野生的布雷氏锥蝽的嗅觉反应。在触角电图（EAG）记录中，我们首先表明，克氏锥蝽的触角对羧酸高度敏感，羧酸是在其栖息地及其脊椎动物宿主的顶空中发现的化合物。然后，我们比较了这两个物种沟槽栓锥感器中嗅觉感觉神经元（OSN）的反应，因为通过单感器记录（SSR），这些感器对这些化合物具有特异性。在克氏锥蝽中，SSR反应显示其调谐宽度比其野生同类更窄，后者对更广泛的化学类别有反应。此外，我们观察到这两个物种对特定挥发物（如乙酸戊酯和丁酰氯）的反应存在显著差异。总之，亲缘关系密切但生态上有差异的克氏锥蝽和布雷氏锥蝽在嗅觉功能上表现出明显差异。考虑到野生物种的自然栖息地正在迅速遭到破坏，以及可能向人类塑造的环境转变，我们预计我们的研究结果将有助于未来设计高效的病媒控制策略。
