An important component of South Africa's malaria elimination agenda is identifying the entomological drivers of residual transmission, especially those that present opportunities for enhanced vector control. Seasonal mosquito density correlates directly with malaria transmission in South Africa. Transmission is highest during the warm rainy season and lowest but not entirely absent during the cooler dry season. The factors that sustain dry-season mosquito survival remain unknown. The aim of this project was therefore to investigate seasonal change in metabolic rate to determine the presence or absence of winter dormancy in malaria vector mosquitoes. Metabolic rate, determined by CO2 production during closed-system respirometry, was measured from wild anophelines collected from KwaZulu-Natal Province, South Africa. Monthly sampling spanned all four seasons (summer, autumn, winter, and spring) in 2017. Anopheles arabiensis and An. parensis specimens formed the majority of the total 437 identified specimens (n = 216 and n = 162, respectively). Metabolic rate data from wild-caught mosquitoes showed no significant seasonal disparities for An. arabiensis and An. parensis males and females. Further laboratory experiments assessed the effect of manipulated photoperiod, representing seasonal day-length changes, on the metabolic rate of colonized An. arabiensis mosquitoes. Simulations of midwinter (10 h:14 h light dark) and midsummer (14 h:10 h) day-length showed no significant effect on the metabolic rate of these mosquitoes. Age (in days) had a significant effect on the metabolic rate of both male and female colonized adult An. arabiensis mosquitoes which may be linked to developmental factors during maturation of adults. These data suggest that the South African populations of the malaria vector species An. arabiensis and An. parensis do not curtail their breeding and foraging activities during the colder and drier winter months. Overwintering by diapause does not appear to be triggered in the adult mosquito stage in An. arabiensis. However, their respective population densities do decrease considerably during winter leading to reduced malaria transmission and the opportunity for control by winter larviciding of known breeding sites.

中文翻译：

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南非阿拉伯按蚊成年人的代谢率没有随季节变化而变化。

南非消除疟疾议程的一个重要组成部分是确定残留传播的昆虫学驱动因素，尤其是那些为加强病媒控制提供机会的驱动因素。季节性蚊子密度与南非的疟疾传播直接相关。在温暖的雨季，传播率最高，而在较冷的干燥季节，传播率最低，但并非完全没有。维持干燥季节蚊子生存的因素仍然未知。因此，该项目的目的是调查代谢率的季节性变化，以确定疟疾媒介蚊子冬季休眠的存在与否。代谢率由封闭系统呼吸测定法中的二氧化碳产生量确定，是从南非夸祖鲁-纳塔尔省采集的野生按蚊中测量的。2017年，每月采样跨越所有四个季节（夏季，秋季，冬季和春季）。阿拉伯按蚊和按蚊。在总共437个已鉴定标本中，parensis标本占多数（分别为n = 216和n = 162）。野外捕获的蚊子的代谢率数据显示，An没有明显的季节性差异。阿拉伯和安南 parensis雄性和雌性。进一步的实验室实验评估了受控的光周期（代表季节性的日长变化）对定殖An代谢速率的影响。阿拉伯蚊子。日冬（10 h：14 h暗）和仲夏（14 h：10 h）的日间模拟显示，这些蚊子的代谢速率没有明显影响。年龄（以天为单位）对定殖的成年男性和成年男性的代谢率都有显着影响。成年人的成熟过程中可能与发育因素有关的阿拉伯蚊子。这些数据表明，疟疾媒介种An的南非种群。阿拉伯和安南 在较冷和干燥的冬季，parensis不会减少其繁殖和觅食活动。滞育造成的越冬似乎并未在An的成年蚊子阶段引发。阿拉伯 但是，它们各自的种群密度在冬季确实会显着下降，从而导致疟疾传播减少，并有机会通过冬季对已知繁殖地点进行幼虫控制来进行控制。在较冷和干燥的冬季，parensis不会减少其繁殖和觅食活动。滞育造成的越冬似乎并未在An的成年蚊子阶段引发。阿拉伯 但是，它们各自的种群密度在冬季确实会显着下降，从而导致疟疾传播减少，并有机会通过冬季对已知繁殖地点进行幼虫控制来进行控制。在较冷和干燥的冬季，parensis不会减少其繁殖和觅食活动。滞育造成的越冬似乎并未在An的成年蚊子阶段引发。阿拉伯 但是，它们各自的种群密度在冬季确实会显着下降，从而导致疟疾传播减少，并有机会通过冬季对已知繁殖地点进行幼虫控制来进行控制。