MIVEGEC, Univ Montpellier, CNRS, IRD, Montpellier, France.
Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso.
Parasit Vectors. 2021 Sep 7;14(1):457. doi: 10.1186/s13071-021-04967-0.
Behavioural shifts in the canonical location and timing of biting have been reported in natural populations of anopheline malaria vectors following the implementation of insecticide-based indoor vector control interventions. These modifications increase the likelihood of human-vector contact and allow mosquitoes to avoid insecticides, both conditions being favourable to residual transmission of the malarial parasites. The biting behaviour of mosquitoes follows rhythms that are under the control of biological clocks and environmental conditions, modulated by physiological states. In this work we explore modifications of spontaneous locomotor activity expressed by mosquitoes in different physiological states to highlight phenotypic variability associated to circadian control that may contribute to explain residual transmission in the field.
The F generation progeny of field-collected Anopheles coluzzii from southwestern Burkina Faso was tested using an automated recording apparatus (Locomotor Activity Monitor, TriKinetics Inc.) under LD 12:12 or DD light regimens in laboratory-controlled conditions. Activity recordings of each test were carried out for a week with 6-day-old females belonging to four experimental treatments, representing factorial combinations of two physiological variables: insemination status (virgin vs inseminated) and gonotrophic status (glucose fed vs blood fed). Chronobiological features of rhythmicity in locomotor activity were explored using periodograms, diversity indices, and generalized linear mixed modelling.
The average strength of activity, onset of activity, and acrophase were modulated by both nutritional and insemination status as well as by the light regimen. Inseminated females showed a significant excess of arrhythmic activity under DD. When rhythmicity was observed in DD, females displayed sustained activity also during the subjective day.
Insemination and gonotrophic status influence the underlying light and circadian control of chronobiological features of locomotor activity. Overrepresentation of arrhythmic chronotypes as well as the sustained activity of inseminated females during the subjective day under DD conditions suggests potential activity of natural populations of A. coluzzii during daytime under dim conditions, with implications for residual transmission of malarial parasites.
在基于杀虫剂的室内病媒控制干预措施实施后，在疟疾病媒按蚊的自然种群中，已报道了在叮咬的典型位置和时间上出现行为变化。这些变化增加了人与病媒接触的可能性，并使蚊子能够躲避杀虫剂，这两种情况都有利于疟原虫的残留传播。蚊子的叮咬行为遵循受生物钟和环境条件控制的节律，并受生理状态调节。在这项工作中，我们探讨了不同生理状态下蚊子自发活动的变化，以突出与昼夜节律控制相关的表型可变性，这可能有助于解释现场的残留传播。
使用自动化记录装置（TriKinetics Inc. 的 Locomotor Activity Monitor），在 LD 12:12 或 DD 光照方案下，对来自布基纳法索西南部的野外采集的按蚊 Anopheles coluzzii 的 F 代后代进行测试。在实验室控制条件下，对来自四个实验处理的 6 天大的雌性蚊子的每一次测试进行为期一周的活动记录，这四个实验处理代表了两个生理变量的因子组合：授精状态（处女与授精）和生殖状态（葡萄糖喂养与血液喂养）。使用周期图、多样性指数和广义线性混合模型探索了运动活动节律的节律特征。
平均活动强度、活动起始时间和高峰时间均受营养和授精状态以及光照方案的调节。在 DD 下，授精的雌性蚊子表现出明显的节律失常活动过多。当在 DD 中观察到节律性时，雌性蚊子在主观白天也会持续活动。
授精和生殖状态影响运动活动节律的节律特征的潜在光和昼夜控制。在 DD 条件下，不规则生物钟类型的过度表现以及授精雌性蚊子在主观白天的持续活动表明，A. coluzzii 自然种群在昏暗条件下白天可能会有潜在的活动，这对疟原虫的残留传播有影响。
