Comparison of the IR LFs in groups (filled points) with the IR LF in clusters (stars). The colour code is the same as in Fig. 4: blue for the nearby groups of Guo et al. (2014) and the Shapley superclusters (Haines et al. 2010) at z< 0.1, black for 0.1 <z< 0.4 groups and 0.15 <z< 0.3 LoCuSS clusters (Haines et al. 2013), and green for 0.4 <z< 0.8 groups and for the 0.6 <z< 0.8 rich cluster LF of Finn et al. (2010). For clarity we only show here the best fit derived with the modified Schechter function of Saunders et al. (1990).