Fig. 2
From: Rapid identification of mosquito species and age by mass spectrometric analysis
Analysis of three Anopheles mosquito species by REIMS. A total of 202 specimens from An. arabiensis (n = 89), An. coluzzii (n = 54) and An. gambiae s.s (n = 59) were killed through freezing and stored at − 20 °C until REIMS analysis. All specimens were female and 4 days old. Principal component–linear discriminant (PC-LD) analysis of the REIMS data within the model building software Offline Model Builder led to a clear separation of the three species (a). After exporting the data matrix (incl. classifications and signal intensities after pre-processing) PC-LDA was repeated in R; results are displayed in form of kernel density (b) and scatter plots (c), shown for both linear discriminants 1 and 2. The group formation correlates with the genetic relatedness of the three groups (d, from [45]); the biggest variance (LD 1) supporting the separation of An. arabiensis, followed by the separation of An. gambiae s.s and An. coluzzii via LD 2. Images of females from all three species are displayed in (e)