To show the differences and similarities of the modulation of miRNA expression during the HSR in different Drosophila strains more clearly, we conducted a time-course analysis that allowed us to monitor the changes in miRNA expression over time. Based on the obtained data, we concluded that all of the Drosophila strains have common (and apparently) species-specific as well as strain-specific features of miRNA expression regulation during the HSR. It is now clear that despite the absence of all of the hsp70 genes, the miRNA expression profiles of the closely related strains w1118 and hsp70− have fewer differences compared with that of the unrelated yw strain. The expression of miRNAs belonging to groups #2 and #3 distinguished the yw strain from the other two and represents a clear example of strain-specific miRNA expression after HS (figure 4b). Moreover, miRNA expression appears to be more robust to HS in the yw strain as observed by the clustering of all of the differentially expressed miRNAs (figure 2b). We have also shown that the yw strain is more thermoresistant compared with the w1118 and hsp70− strains (figure 1c). It is possible that the increased thermoresistance of the yw strain may be partly explained by strain-specific properties of the miRNA-mediated HSR.