Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar-es-Salaam, Tanzania.
Sci Rep. 2020 Sep 3;10(1):14527. doi: 10.1038/s41598-020-71187-4.
Despite significant reductions in malaria transmission across Africa since 2000, progress is stalling. This has been attributed to the development of insecticide resistance and behavioural adaptations in malaria vectors. Whilst insecticide resistance has been widely investigated, there is poorer understanding of the emergence, dynamics and impact of mosquito behavioural adaptations. We conducted a longitudinal investigation of malaria vector host choice over 3 years and resting behaviour over 4 years following a mass long-lasting insecticidal nets (LLINs) distribution in Tanzania. By pairing observations of mosquito ecology with environmental monitoring, we quantified longitudinal shifts in host-choice and resting behaviour that are consistent with adaptation to evade LLINs. The density of An. funestus s.l., declined significantly through time. In tandem, An. arabiensis and An. funestus s.l. exhibited an increased rate of outdoor relative to indoor resting; with An. arabiensis reducing the proportion of blood meals taken from humans in favour of cattle. By accounting for environmental variation, this study detected clear evidence of intra-specific shifts in mosquito behaviour that could be obscured in shorter-term or temporally-coarse surveys. This highlights the importance of mosquito behavioural adaptations to vector control, and the value of longer-term behavioural studies.
尽管自 2000 年以来非洲的疟疾传播显著减少，但进展却停滞不前。这归因于疟疾传播媒介对杀虫剂的抗药性和行为适应性的发展。虽然对杀虫剂抗药性进行了广泛的研究，但对蚊子行为适应性的出现、动态和影响的理解较差。我们在坦桑尼亚大规模长效杀虫剂处理蚊帐（LLINs）分发后，进行了为期 3 年的疟疾传播媒介宿主选择和为期 4 年的休息行为的纵向调查。通过将蚊子生态学的观察与环境监测相结合，我们量化了与逃避 LLINs 相适应的宿主选择和休息行为的纵向变化。An. funestus s.l. 的密度随时间显著下降。与此同时，An. arabiensis 和 An. funestus s.l. 的户外相对室内休息率增加；An. arabiensis 减少了从人类身上取食血液的比例，转而更喜欢牛。通过考虑环境变化，本研究检测到蚊子行为的明显的种内变化证据，这在短期或时间粗糙的调查中可能会被掩盖。这突显了蚊子行为适应性对病媒控制的重要性，以及长期行为研究的价值。
