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.

在农业地区大量使用杀虫剂往往会导致附近蚊子幼虫繁殖地受到污染。接触复杂的农用化学品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按蚊幼虫繁殖地的农药残留是否会影响成虫对常用杀虫剂的耐受性。我们专注于 Fludora® Fusion，这是一种病媒控制杀虫剂配方，结合了两种具有不同作用方式的杀虫剂（溴氰菊酯和噻虫胺）。一个。冈比亚在科特迪瓦高度活跃的农业区，幼虫暴露于亚致死剂量的农用化学杀虫剂混合物中。使用 Fludora Fusion 混合物及其两种杀虫剂成分（溴氰菊酯和噻虫胺）在幼虫期暴露或未暴露于农用化学品的成蚊之间进行了比较生物测定。然后使用 RNA 测序对幼虫和成虫进行转录组学分析，以研究观察到的表型变化的分子机制。生物测定显示，在幼虫暴露于农用化学品后，成年雌性对噻虫胺（2.5 倍）和 Fludora Fusion 混合物（2.2 倍）的耐受性显着增加。未观察到对溴氰菊酯的耐受性显着增加，这表明杀虫剂暴露主要通过作用于噻虫胺的机制影响 Fludora Fusion 混合物的成虫功效。转录组学分析揭示了农用化学品诱导各种抗性机制的潜力，包括角质层蛋白、解毒作用和改变的杀虫剂螯合。这些结果表明，尽管 Fludora Fusion 混合物对成虫病媒控制有效，但其功效可能会受到生态环境的局部影响。本研究还表明，尽管农用化学品的使用与病媒控制杀虫剂之间的复杂相互作用很难在现场破译，但仍必须在杀虫剂抗性管理计划的背景下加以考虑。