Wagoner Kaira M, Lehmann Tovi, Huestis Diana L, Ehrmann Brandie M, Cech Nadja B, Wasserberg Gideon
Department of Biology, University of North Carolina Greensboro, 235 Eberhart Bldg, Greensboro, NC 27402, USA.
Parasit Vectors. 2014 Jun 26;7:294. doi: 10.1186/1756-3305-7-294.
Increased understanding of the dry-season survival mechanisms of Anopheles gambiae in semi-arid regions could benefit vector control efforts by identifying weak links in the transmission cycle of malaria. In this study, we examined the effect of photoperiod and relative humidity on morphologic and chemical traits known to control water loss in mosquitoes.
Anopheles gambiae body size (indexed by wing length), mesothoracic spiracle size, and cuticular hydrocarbon composition (both standardized by body size) were examined in mosquitoes raised from eggs exposed to short photoperiod and low relative humidity, simulating the dry season, or long photoperiod and high relative humidity, simulating the wet-season.
Mosquitoes exposed to short photoperiod exhibited larger body size and larger mesothoracic spiracle length than mosquitoes exposed to long photoperiod. Mosquitoes exposed to short photoperiod and low relative humidity exhibited greater total cuticular hydrocarbon amount than mosquitoes exposed to long photoperiod and high relative humidity. In addition, total cuticular hydrocarbon amount increased with age and was higher in mated females. Mean n-alkane retention time (a measure of cuticular hydrocarbon chain length) was lower in mosquitoes exposed to short photoperiod and low relative humidity, and increased with age. Individual cuticular hydrocarbon peaks were examined, and several cuticular hydrocarbons were identified as potential biomarkers of dry- and wet-season conditions, age, and insemination status.
Results from this study indicate that morphological and chemical changes underlie aestivation of Anopheles gambiae and may serve as biomarkers of aestivation.
深入了解冈比亚按蚊在半干旱地区的旱季生存机制，有助于通过识别疟疾传播周期中的薄弱环节来加强病媒控制工作。在本研究中，我们考察了光周期和相对湿度对已知控制蚊虫水分流失的形态学和化学特征的影响。
将冈比亚按蚊的卵分别置于模拟旱季的短光周期和低相对湿度条件下，或模拟雨季的长光周期和高相对湿度条件下饲养，之后检测其身体大小（以翅长为指标）、中胸气门大小以及表皮碳氢化合物组成（均按身体大小标准化）。
与暴露于长光周期的蚊子相比，暴露于短光周期的蚊子体型更大，中胸气门长度更长。与暴露于长光周期和高相对湿度的蚊子相比，暴露于短光周期和低相对湿度的蚊子表皮碳氢化合物总量更多。此外，表皮碳氢化合物总量随年龄增长而增加，且交配后的雌蚊含量更高。暴露于短光周期和低相对湿度的蚊子的平均正构烷保留时间（表皮碳氢化合物链长度的一种度量）较低，并随年龄增长而增加。对单个表皮碳氢化合物峰进行了检测，确定了几种表皮碳氢化合物作为旱季和雨季条件、年龄及受精状态的潜在生物标志物。
本研究结果表明，形态学和化学变化是冈比亚按蚊夏眠的基础，可能作为夏眠的生物标志物。
