Laboratory of Malaria and Vector Research, National Institutes of Health, Bethesda, MD, USA.
Parasit Vectors. 2014 Apr 3;7:163. doi: 10.1186/1756-3305-7-163.
The African malaria mosquito, Anopheles gambiae, needs surface water in order to lay their eggs. In many parts of Africa, there are dry periods varying from days to months in length when suitable larval sites are not available and female mosquitoes experience oviposition-site deprivation (OSD). Previous studies have shown that egg-laying and egg-hatching rates were reduced due to OSD. Here, we assessed its effect on longevity and bloodfeeding rate of Anopheles gambiae. We predicted that OSD will increase mosquito longevity and the aptitude of mosquitoes to take additional blood meals; importantly, these changes will increase its vectorial capacity.
To measure the effect of OSD, four treatments were utilized: two oviposition-deprived groups, one of which was bloodfed once (OBOD) and one that was bloodfed weekly (MBOD); a non-oviposition-deprived, weekly bloodfed control group (MBC); and a blood-deprived age-control group (BD). Mortality was assessed daily and bloodfeeding rate was measured at weekly intervals.
Under OSD, survival of female A. gambiae was reduced by 10-20%, reflecting reduction of the MBOD and OBOD groups from the MBC group, respectively. Likewise, bloodfeeding response during three weeks of OSD was reduced but the reduction varied as a function of time from the last blood meal.
These results indicate that OSD is expected to reduce A. gambiae vectorial capacity and that OSD alone does not act as cue used by female mosquitoes to switch into a dormant state of extended survivorship with reproductive quiescence.
非洲疟蚊（Anopheles gambiae）需要地表水才能产卵。在非洲的许多地区，存在持续数天到数月不等的干旱期，此时缺乏适宜的幼虫栖息地，雌性蚊子会经历产卵地剥夺（OSD）。先前的研究表明，OSD 会降低产卵和孵化率。在这里，我们评估了 OSD 对疟蚊寿命和吸血率的影响。我们预测，OSD 将增加蚊子的寿命和蚊子获取额外血液的能力；重要的是，这些变化将增加其传播能力。
为了测量 OSD 的影响，我们采用了四种处理方法：两个产卵剥夺组，其中一个接受了一次血液喂食（OBOD），另一个每周接受一次血液喂食（MBOD）；一个非产卵剥夺、每周接受血液喂食的对照组（MBC）；以及一个血液剥夺的年龄对照组（BD）。每天评估死亡率，每周测量一次吸血率。
在 OSD 下，雌性疟蚊的存活率降低了 10-20%，这反映了 MBOD 和 OBOD 组分别相对于 MBC 组的减少。同样，在 OSD 的三周内，吸血反应减少，但减少的程度随上次血液摄入后的时间而变化。
这些结果表明，OSD 预计会降低疟蚊的传播能力，而且 OSD 本身不会像雌性蚊子用来进入休眠状态的线索那样，导致延长的生存和生殖静止。
