Gary R E, Foster W A
Department of Entomology, the Ohio State University, 1735 Neil Avenue, Columbus, OH 43210, USA.
J Med Entomol. 2001 Jan;38(1):22-8. doi: 10.1603/0022-2585-38.1.22.
Although females of most mosquito species are known to use sugar as a necessary source of energy, female Anopheles gambiae Giles sensu stricto are thought to use it facultatively or not at all. However, field evidence of sugar-free living is inconclusive, and the implications for reproductive fitness and vectorial capacity are unknown. To evaluate the role that sugar may play in the ecology of these mosquitoes, mated female An. gambiae in the laboratory were given access to either no food (water only), 10% sucrose, human blood, or human blood + 10% sucrose, and comparisons of daily mortality, fecundity, and biting frequency were made. The effect of sugar availability on vectorial capacity and the intrinsic rate of increase, a measure of fitness, then were determined. Females (pooled and individual) given blood + sugar lived significantly longer than did those on the other diets. Daily fecundity was higher for females given blood alone than for those fed blood + sugar (13 versus 9 eggs per female daily). However, total fecundity and intrinsic rate of increase were not affected by sugar availability. Biting frequency was significantly higher (0.41 versus 0.26 bites per female per day) for females given blood alone. Despite the reduced survivorship, exclusive blood-feeding led to a theoretically higher vectorial capacity for Plasmodium falciparum at 27 degrees C. These data indicate that female An. gambiae could replace sugar with increased blood feeding without suppressing reproductive fitness. Increased blood feeding could, in turn, increase the rate of malaria transmission and may explain the unusual efficiency of this vector.
虽然已知大多数蚊种的雌蚊会将糖分作为必要的能量来源，但冈比亚按蚊狭义种（Anopheles gambiae Giles sensu stricto）的雌蚊被认为是偶尔利用糖分或根本不利用。然而，无糖分生存的野外证据并不确凿，其对生殖适合度和传病能力的影响也尚不清楚。为了评估糖分在这些蚊子生态中的作用，在实验室中给已交配的冈比亚按蚊雌蚊提供以下几种食物选择：不提供食物（仅提供水）、10%的蔗糖、人血，或人血 + 10%的蔗糖，然后比较每日死亡率、繁殖力和叮咬频率。接着确定糖分供应对传病能力和内在增长率（一种适合度指标）的影响。摄入血液 + 糖分的雌蚊（混合及个体）的存活时间显著长于其他饮食组的雌蚊。仅摄入血液的雌蚊每日繁殖力高于摄入血液 + 糖分的雌蚊（分别为每日每只雌蚊产13个卵和9个卵）。然而，总繁殖力和内在增长率不受糖分供应的影响。仅摄入血液的雌蚊叮咬频率显著更高（分别为每日每只雌蚊0.41次叮咬和0.26次叮咬）。尽管存活率降低，但仅以血液为食在理论上会使恶性疟原虫在27摄氏度时的传病能力更高。这些数据表明，冈比亚按蚊雌蚊可以通过增加血液摄入来替代糖分，而不会抑制生殖适合度。反过来，增加血液摄入可能会提高疟疾传播率，这或许可以解释这种媒介的非凡效率。
