⟨[ X/Fe ] ⟩ − T_C trends for planet host stars. The stars are divided into six categories, three corresponding to stars with known planets but no debris discs, namely, stars hosting cool Jupiters (light-blue open circles), low-mass planet hosts (pink earth symbols), and stars hosting hot Jupiters (red filled circles). The SWDP sample is divided into the same categories: stars with debris discs and cool Jupiters (pink filled squares), debris discs and low-mass planets (cyan filled stars), and stars harbouring debris discs and hot Jupiters (light green asterisks). Each planet host subsample is shown against its corresponding SWDP subsample (e.g. stars with cool Jupiters vs. stars with discs and cool Jupiters) with an offset of −0.15 between the samples for the sake of clarity. The offset between the samples of cool, low-mass, and hot Jupiters hosts is −0.75. Unweighted fits are shown by continuous lines, while weighted fits are plotted in dashed lines. For guidance, the derived slopes from the unweighted fits are shown in the plots (units of 10^-5 dex/K). The left panel shows the ⟨[ X/Fe ] ⟩ − T_C trends when all elements (volatiles and refractories) are taken into account whilst the right one shows the ⟨[ X/Fe ] ⟩ − T_C trends when only refractories are considered.