PACS line fluxes versus L_TIR. The DGS galaxies are represented by filled circles (compact sample) color-coded by metallicity. The red asterisks are the galaxies from Brauher et al. (2008) and the blue asterisks are the low-metallicity sources originally published by Hunter et al. (2001). The orange rectangles are the HERUS data from Farrah et al. (2013) and the red rectangles are the SHINING data from Graciá-Carpio et al. (2011). Spearman correlation coefficients applied to the DGS compact sample are indicated in the top left corner (when found above the chosen significance level and with more than 8 data points).