Ifakara Health Institute, Environmental Health and Ecological Sciences, P,O, Box 53, Ifakara, Tanzania.
Parasit Vectors. 2013 Oct 14;6(1):298. doi: 10.1186/1756-3305-6-298.
Determining the age of malaria vectors is essential for evaluating the impact of interventions that reduce the survival of wild mosquito populations and for estimating changes in vectorial capacity. Near infra-red spectroscopy (NIRS) is a simple and non-destructive method that has been used to determine the age and species of Anopheles gambiae s.l. by analyzing differences in absorption spectra. The spectra are affected by biochemical changes that occur during the life of a mosquito and could be influenced by senescence and also the life history of the mosquito, i.e., mating, blood feeding and egg-laying events.
To better understand these changes, we evaluated the influence of mosquito physiological status on NIR energy absorption spectra. Mosquitoes were kept in individual cups to permit record keeping of each individual insect's life history. Mosquitoes of the same chronological age, but at different physiological stages, were scanned and compared using cross-validations.
We observed a slight trend within some physiological stages that suggest older insects tend to be predicted as being physiologically more mature. It was advantageous to include mosquitoes of different chronological ages and physiological stages in calibrations, as it increases the robustness of the model resulting in better age predictions.
Progression through different physiological statuses of An. arabiensis influences the chronological age prediction by the NIRS. Entomologists that wish to use NIR technology to predict the age of field-caught An. gambiae s.l from their study area should use a calibration developed from their field strain using mosquitoes of diverse chronological ages and physiological stages to increase the robustness and accuracy of the predictions.
确定疟疾病媒的年龄对于评估减少野生蚊群存活率的干预措施的影响以及估计媒介传播能力的变化至关重要。近红外光谱（NIRS）是一种简单且非破坏性的方法，通过分析吸收光谱的差异，已被用于确定冈比亚按蚊复合体的年龄和种类。光谱受蚊生命周期中发生的生化变化影响，可能受到衰老和蚊的生活史（即交配、吸血和产卵事件）的影响。
为了更好地理解这些变化，我们评估了蚊生理状态对近红外能量吸收光谱的影响。将蚊子保存在单独的杯子中，以记录每个个体昆虫的生活史。对具有相同chronological age 的蚊子，但处于不同生理阶段的蚊子进行扫描，并使用交叉验证进行比较。
我们观察到一些生理阶段内存在轻微的趋势，表明较老的昆虫往往被预测为生理上更成熟。在定标中包含不同chronological age 和生理阶段的蚊子是有利的，因为它增加了模型的稳健性，从而产生更好的年龄预测。
在不同的生理状态下，An. arabiensis 的进展会影响 NIRS 对chronological age 的预测。如果昆虫学家希望使用 NIR 技术根据其研究区域从野外捕获的 An. gambiae s.l. 来预测年龄，他们应该使用从其野外种群中开发的定标，该定标应使用具有不同chronological age 和生理阶段的蚊子，以提高预测的稳健性和准确性。
