Australian Defence Force Malaria and Infectious Disease Institute, Gallipoli Barracks, Enoggera, Australia.
Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia.
PLoS Negl Trop Dis. 2021 Feb 5;15(2):e0009121. doi: 10.1371/journal.pntd.0009121. eCollection 2021 Feb.
The development of insecticide resistance in mosquitoes can have pleiotropic effects on key behaviours such as mating competition and host-location. Documenting these effects is crucial for understanding the dynamics and costs of insecticide resistance and may give researchers an evidence base for promoting vector control programs that aim to restore or conserve insecticide susceptibility.
We evaluated changes in behaviour in a backcrossed strain of Aedes aegypti, homozygous for two knockdown resistance (kdr) mutations (V1016G and S989P) isolated in an otherwise fully susceptible genetic background. We compared biting activity, host location behaviours, wing beat frequency (WBF) and mating competition between the backcrossed strain, and the fully susceptible and resistant parental strains from which it was derived. The presence of the homozygous kdr mutations did not have significant effects on blood avidity, the time to locate a host, or WBF in females. There was, however, a significant reduction in mean WBF in males and a significant reduction in estimated male mating success (17.3%), associated with the isolated kdr genotype.
Our results demonstrate a cost of insecticide resistance associated with an isolated kdr genotype and manifest as a reduction in male mating success. While there was no recorded difference in WBF between the females of our strains, the significant reduction in male WBF recorded in our backcrossed strain might contribute to mate-recognition and mating disruption. These consequences of resistance evolution, especially when combined with other pleiotropic fitness costs that have been previously described, may encourage reversion to susceptibility in the absence of insecticide selection pressures. This offers justification for the implementation of insecticide resistance management strategies based on the rotation or alternation of different insecticide classes in space and time.
蚊虫对杀虫剂产生抗药性会对交配竞争和宿主定位等关键行为产生多效性影响。记录这些影响对于理解杀虫剂抗药性的动态和成本至关重要，并且可能为研究人员提供一个证据基础，以促进旨在恢复或保护杀虫剂敏感性的病媒控制计划。
我们评估了在 Aedes aegypti 的回交品系中行为的变化，该品系在完全敏感的遗传背景中分离出了两个击倒抗性（kdr）突变（V1016G 和 S989P）的纯合子。我们比较了回交品系与完全敏感和抗性的亲本品系之间的叮咬活性、宿主定位行为、翅膀拍打频率（WBF）和交配竞争。纯合 kdr 突变的存在对血液亲和力、找到宿主的时间或雌性的 WBF 没有显著影响。然而，雄性的平均 WBF 显著降低，与分离的 kdr 基因型相关的雄性交配成功率（17.3%）显著降低。
我们的结果表明，与孤立的 kdr 基因型相关的杀虫剂抗药性存在成本，表现为雄性交配成功率降低。虽然我们的菌株雌蝇之间没有记录到 WBF 的差异，但在回交品系中记录到的雄性 WBF 显著降低可能会导致配偶识别和交配中断。这些抗药性进化的后果，特别是当与以前描述的其他多效性适应成本结合时，可能会鼓励在没有杀虫剂选择压力的情况下恢复敏感性。这为基于不同杀虫剂类别在空间和时间上的轮换或交替实施杀虫剂抗药性管理策略提供了理由。
