Fig. 3From: Characterization of melanic and non-melanic forms in domestic and peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae)K-means clustering analysis. a Plot of the curve of the total within-cluster sum of square for 10 K-values (elbow method). The optimal number of clusters suggested by this method (two) is indicated with a dashed line. b Biplot derived from the first two axes of a principal components analysis showing the spatial distribution of the two clusters derived from a K-means clustering analysis (K = 2)Back to article page