Nikbakhtzadeh Mahmood R, Fuentes Yelissa
Department of Health Science and Human Ecology, California State University, San Bernardino, CA 92407-2393.
J Am Mosq Control Assoc. 2022 Sep 1;38(3):198-207. doi: 10.2987/22-7059.
Glyphosate is one of the most common herbicides used to control weeds in the USA. This herbicide can impact the mosquito life cycle through being carried to mosquito habitats by runoff. This study investigates the effects of glyphosate on the larval development and oviposition of a laboratory colony of Culex quinquefasciatus. Our experiments indicated that a concentration of 1 g/liter glyphosate was lethal to larval instars or the larvae impacted were either unable to molt to pupae or never emerged as adults. Larval instars exposed to 0.5 g/liter glyphosate experienced a similar impact; however, the larval stage was extended and pupation was considerably delayed. Mosquitoes oviposited in 0.5 g/liter glyphosate laid the same number of egg rafts as in water, but a considerably lower number of eggs exposed to glyphosate hatched as first instars. If gravid females laid their eggs in 1 g/liter glyphosate versus water, the difference between the 2 groups would be statistically significant and a very low number of eggs exposed to glyphosate could ever hatch into larvae. In an oviposition assay carried out in a cage with 3 choices of water, 0.5 g/liter, and 1 g/liter glyphosate, a higher number of egg rafts were laid in water, followed by 0.5 g/liter and 1 g/liter glyphosate concentrations, respectively. Our study indicated such a severe effect of glyphosate on all immature stages of Cx. quinquefasciatus that no adult could ever emerge.
草甘膦是美国用于控制杂草的最常见除草剂之一。这种除草剂可通过径流携带至蚊子栖息地，从而影响蚊子的生命周期。本研究调查了草甘膦对实验室饲养的致倦库蚊幼虫发育和产卵的影响。我们的实验表明，浓度为1克/升的草甘膦对幼虫龄期具有致死性，或者受影响的幼虫要么无法蜕皮变为蛹，要么永远无法羽化为成虫。暴露于0.5克/升草甘膦的幼虫龄期也受到了类似影响；然而，幼虫阶段延长，化蛹显著延迟。在0.5克/升草甘膦中产卵的蚊子产下的卵筏数量与在水中相同，但暴露于草甘膦的卵孵化出的一龄幼虫数量要少得多。如果怀孕雌蚊在1克/升草甘膦中与在水中产卵，两组之间的差异将具有统计学意义，且暴露于草甘膦的卵能够孵化成幼虫的数量非常少。在一个笼子里进行的产卵试验中，有三种选择：水、0.5克/升和1克/升草甘膦，在水中产下的卵筏数量更多，其次分别是0.5克/升和1克/升草甘膦浓度的情况。我们的研究表明，草甘膦对致倦库蚊所有未成熟阶段都有如此严重的影响，以至于永远不会有成蚊出现。
