Clustering of transcripts differentially expressed across strains. The analysis was performed on the 413 known transcripts significantly differentially expressed in any insecticide-selected strain compared to the susceptible strain. Clustering was based on Euclidean distance of fold changes as compared to the susceptible strain and complete linkage algorithm. Pie charts describe biological functions affected within main clusters based on the number of transcripts assigned to each function. Stars indicate biological functions significantly enriched compared to their representation among all detected transcripts (Fisher’s test adjusted P value: * ≤ 0.05, ** ≤ 0.01, *** ≤ 0.001). The total number of transcripts constituting each cluster is indicated. The number of transcripts with predicted functions used for building each pie chart is shown within brackets.