Ministry of Health, Community Development, Gender, Elderly and Children, Vector Control Training Centre, P.O. Box 136, Muheza, Tanzania.
University of Dar es Salaam, Dar es Salaam, Tanzania.
Malar J. 2020 Sep 1;19(1):318. doi: 10.1186/s12936-020-03395-2.
Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito's life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.) METHODS: In the laboratory and in large (80 m) outdoor cages in Tanzania, nulliparous and parous A. gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odours that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments.
In the laboratory nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings nulliparous were significantly more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness.
Nulliparous and parous A. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.
蚊子利用气味寻找能量资源、血液宿主和产卵场所。虽然这些气味来源在蚊子的生活史中通常是时空分离的，但本研究探讨了花香和人类模拟合成挥发物的组合在多大程度上吸引疟疾传播媒介冈比亚按蚊（s.s.）。
在实验室和坦桑尼亚的大型（80 米）户外笼中，未交配和已交配的冈比亚按蚊 s.s. 在人类皮肤挥发物混合物（Skin Lure）、花香挥发物混合物（Vectrax）或两者的组合之间进行选择。混合物由分别在嗅觉电路、表达嗅觉受体（ORs）和离子型受体（IRs）的感觉神经元中诱导不同、不重叠的激活模式的气味组成。比较处理之间的捕获量。
在实验室中，未交配和已交配的蚊子更喜欢皮肤气味及其组合，而不是花香气味。然而，在半野外环境中，未交配的蚊子被花香气味捕获的数量显著增加，而已交配的蚊子则没有观察到差异。花香和人类挥发物的组合并没有增加吸引力。
未交配和已交配的冈比亚按蚊 s.s. 被来自蚊子生活史中时空分离资源的气味组合（花香和人类挥发物）所吸引。这是有利的，因为蚊子种群由个体组成，它们的营养和发育状态引导它们转向不同的气味来源，吸引蚊子的诱饵与蚊子的状态无关，可以提高整体效果，并在监测和控制中使用。然而，在半野外环境中，花香和皮肤气味的组合并没有增加吸引力，尽管这些混合物激活了不同的感觉神经元。相反，蚊子的偏好似乎是由从花香到对气味混合物的更一般吸引力的血液餐经验调节的。结果从气味编码和应用角度进行了讨论。
