The species-specific mode of action for DEET and many other mosquito repellents is often unclear. Confusion may arise for many reasons. First, the response of a single mosquito species is often used to represent all mosquito species. Second, behavioural studies usually test the effect of repellents on mosquito attraction towards human odorants, rather than their direct repulsive effect on mosquitoes. Third, the mosquito sensory neuron responses towards repellents are often not directly examined. A close proximity response assay was used to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii, Aedes aegypti and Culex quinquefasciatus mosquitoes. Additionally, the behavioural assay and calcium imaging recordings of antennae were used to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET. Anopheles coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antennae than lower concentrations. Finally, changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviours. The findings described here suggest that different species of mosquitoes have different behavioural responses to repellents. The data further suggest that high-odour concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioural responses. Finally, DEET can decrease the neuronal and behavioural response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency.

中文翻译：

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驱蚊剂介导蚊子中特定物种的嗅觉行为。

DEET和许多其他驱蚊剂的特定物种作用方式通常是不清楚的。出于多种原因可能会引起混乱。首先，单个蚊子物种的反应常被用来代表所有蚊子物种。第二，行为研究通常测试驱蚊剂对蚊子吸引人的气味的作用，而不是驱蚊剂对蚊子的直接排斥作用。第三，通常不直接检查蚊子对驱虫剂的感觉神经元反应。使用近距离响应测定法测试了六种驱蚊剂对嗜水按蚊，埃及伊蚊和库克斯库克斯昆蚊的直接排斥作用。另外，使用触角的行为测定和钙成像记录来测试An的反应。蚊子以不同浓度的两种人类气味（1-辛烯-3-醇和苯甲醛）以及驱蚊剂柠檬草油和对薄荷3,8-二醇（PMD）与DEET的混合物。柠檬草油和PMD驱除了库蚊按蚊，而Ae则驱蚊。埃及和Cx。柠檬草油，PMD，丁香酚和DEET可以驱除quinquefasciatus蚊子。另外，高浓度的1-辛烯-3-醇和苯甲醛具有驱避作用，并在An上激活更多的嗅觉受体神经元。口气比浓度低。最后，对驱避剂混合物的嗅觉响应的变化反映了排斥行为的变化。这里描述的发现表明，不同种类的蚊子对驱蚊剂的行为反应不同。数据进一步表明，高浓度的气味可能会募集驱避剂敏感的神经元，或通常会激发许多嗅觉神经元，从而产生驱避行为反应。最后，DEET可以降低An的神经元和行为反应。蚊子朝PMD前进，但不朝柠檬草油前进。总体而言，这些研究可以帮助按物种区分驱蚊剂，指导有关有效驱蚊剂混合物的决策，并最终确定介导驱蚊剂的蚊子中的嗅觉神经元和受体。