Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
Centre for Environmental Policy, Imperial College London, 16-18 Princes Gardens, London, SW7 1NE, UK.
Malar J. 2020 Jul 6;19(1):236. doi: 10.1186/s12936-020-03306-5.
Marking mosquitoes is vital for mark-release-recapture and many laboratory studies, but their small size precludes the use of methods that are available for larger animals such as unique identifier tags and radio devices. Fluorescent dust is the most commonly used method to distinguish released individuals from the wild population. Numerous colours and combinations can be used, however, dust sometimes affects longevity and behaviour so alternatives that do not have these effects would contribute substantially. Rhodamine B has previously been demonstrated to be useful for marking adult Aedes aegypti males when added to the sugar meal. Unlike dust, this also marked the seminal fluid making it possible to detect matings by marked males in the spermatheca of females. Here, marking of Anopheles gambiae sensu stricto with rhodamine B and uranine was performed to estimate their potential contribution.
Two fluorescent markers, rhodamine B and uranine, were dissolved in sugar water and fed to adult An. gambiae. Concentrations that are useful for marking individuals and seminal fluid were determined. The effects on adult longevity, the durability of the marking and detection of the marker in mated females was determined. Male mating competitiveness was also evaluated.
Rhodamine B marking in adults is detectable for at least 3 weeks, however uranine marking declines with time and at low doses can be confused with auto-fluorescence. Both can be used for marking seminal fluid which can be detected in females mated by marked males, but, again, at low concentrations uranine-marking is more easily confused with the natural fluorescence of seminal fluid. Neither dye affected mating competitiveness.
Both markers tested could be useful for field and laboratory studies. Their use has substantial potential to contribute to a greater understanding of the bio-ecology of this important malaria vector. Rhodamine B has the advantage that it appears to be permanent and is less easily confused with auto-fluorescence. The primary limitation of both methods is that sugar feeding is necessary for marking and adults must be held for at least 2 nights to ensure all individuals are marked whereas dusts provide immediate and thorough marking.
标记蚊子对于标记释放再捕获和许多实验室研究至关重要，但由于它们的体型较小，无法使用针对较大动物的方法，如独特标识符标签和无线电设备。荧光粉尘是区分释放个体与野生种群的最常用方法。可以使用多种颜色和组合，但是粉尘有时会影响寿命和行为，因此不会产生这些影响的替代方法将有很大贡献。先前已经证明，在糖餐中添加罗丹明 B 可用于标记成年埃及伊蚊雄蚊。与粉尘不同，这也标记了精液，使得可以通过标记的雄蚊在雌性的精囊鞘中检测交配。在这里，对冈比亚按蚊进行了罗丹明 B 和尿嘧啶的标记，以评估它们的潜在贡献。
将两种荧光标记物，罗丹明 B 和尿嘧啶，溶解在糖水后喂给成年按蚊。确定了可用于标记个体和精液的浓度。测定了对成虫寿命，标记耐久性以及在交配雌性中检测标记的影响。还评估了雄性的交配竞争力。
成年个体的罗丹明 B 标记至少可检测到 3 周，但尿嘧啶标记会随时间而下降，并且在低剂量下可能会与自发荧光混淆。两者都可用于标记精液，可在交配的雌性中检测到由标记的雄性，但同样，在低浓度下，尿嘧啶标记更容易与精液的自然荧光混淆。两种染料均未影响交配竞争力。
两种测试的标记物都可用于野外和实验室研究。它们的使用具有很大的潜力，可以帮助我们更好地了解这种重要的疟疾传播媒介的生物生态学。罗丹明 B 的优势在于它似乎是永久性的，并且不易与自发荧光混淆。这两种方法的主要局限性是标记需要通过喂糖来完成，并且成年个体必须至少保持 2 晚以确保所有个体都被标记，而粉尘则可以立即进行全面标记。
