Comparison of six MALDI-MS spectra, 3.3 to 4.6 kDa. The upper three spectra (red) were obtained with three different flies from D. ananassae, whereas the lower three (blue) were from different (female) D. melanogaster specimens. Peaks detected by FlexAnalysis are indicated for two representative spectra. Peaks highlighted in green were used for stringent species discrimination in the generation of the final dendrogram (Fig. 4).