Univ. Grenoble-Alpes, Univ. Savoie Mont Blanc, CNRS, LECA, 38000 Grenoble, France.
Centre Suisse de la Recherche Scientifique en Côte d'Ivoire, Côte d'Ivoire.
Aquat Toxicol. 2022 Jul;248:106181. doi: 10.1016/j.aquatox.2022.106181. Epub 2022 Apr 26.
The heavy use of pesticides in agricultural areas often leads to the contamination of nearby mosquito larvae breeding sites. Exposure to complex mixtures of agrochemicals can affect the insecticide sensitivity of mosquito larvae. Our study objective was to determine whether agrochemical residues in Anopheline larval breeding sites can affect the tolerance of adults to commonly used adulticides. We focussed on Fludora® Fusion, a vector control insecticide formulation combining two insecticides (deltamethrin and clothianidin) with different modes of action. An. gambiae larvae were exposed to a sub-lethal dose of a mixture of agrochemical pesticides used in a highly active agricultural area on the Ivory Coast. Comparative bioassays with Fludora Fusion mixture and its two insecticide components (deltamethrin and clothianidin) were carried out between adult mosquitoes exposed or not to the agrochemicals at the larval stage. A transcriptomic analysis using RNA sequencing was then performed on larvae and adults to study the molecular mechanisms underlying the phenotypic changes observed. Bioassays revealed a significantly increased tolerance of adult females to clothianidin (2.5-fold) and Fludora Fusion mixture (2.2-fold) following larval exposure to agrochemicals. Significantly increased tolerance to deltamethrin was not observed suggesting that insecticide exposure affects the adult efficacy of the Fludora Fusion mixture mainly through mechanisms acting on clothianidin. Transcriptomic analysis revealed the potential of agrochemicals to induce various resistance mechanisms including cuticle proteins, detoxification action and altered insecticide sequestration. These results suggest that although the Fludora Fusion mixture is effective for adult vector control, its efficacy may be locally affected by the ecological context. The present study also suggests that, although the complex interactions between the use of agrochemicals and vector control insecticides are difficult to decipher in the field, they still must be considered in the context of insecticide resistance management programmes.
农业区大量使用农药通常会导致附近蚊子幼虫滋生地受到污染。接触到复杂的农药混合物会影响蚊子幼虫对杀虫剂的敏感性。我们的研究目的是确定蚊虫幼虫滋生地中的农药残留是否会影响成虫对常用成虫杀虫剂的耐受性。我们专注于 Fludora® Fusion，这是一种结合了两种不同作用模式的杀虫剂（氯菊酯和噻虫啉）的蚊虫控制杀虫剂配方。用在科特迪瓦一个高度活跃的农业区使用的农药混合物对 An. gambiae 幼虫进行亚致死剂量暴露。在成虫阶段暴露或不暴露于农药的情况下，对 Fludora Fusion 混合物及其两种杀虫剂成分（氯菊酯和噻虫啉）进行了比较生物测定。然后，对幼虫和成虫进行 RNA 测序转录组分析，以研究观察到的表型变化背后的分子机制。生物测定结果表明，幼虫暴露于农药后，成年雌性对氯菊酯（2.5 倍）和 Fludora Fusion 混合物（2.2 倍）的耐受性显著增加。未观察到对氯菊酯的耐受性显著增加，这表明杀虫剂暴露主要通过作用于噻虫啉的机制影响 Fludora Fusion 混合物对成虫的功效。转录组分析显示，农药具有诱导各种抗性机制的潜力，包括角质蛋白、解毒作用和改变杀虫剂蓄积。这些结果表明，尽管 Fludora Fusion 混合物对成虫病媒控制有效，但在局部情况下，其功效可能会受到生态背景的影响。本研究还表明，尽管在田间很难破译农药使用与病媒控制杀虫剂之间的复杂相互作用，但在制定杀虫剂抗性管理计划时仍必须考虑这些相互作用。
