The literature search identified 79 species of isopods that were studied with respect to at least one of the following relationships: clutch size with female size (A), offspring size with female size (B), and clutch size with offspring size (C). Each graph shows how frequently a given nature of each relationship was found among the studied isopod species. The exact number of species for which the relationships A, B, C were evaluated is given by N. For each type of the relationships A, B, C each species was classified according to the nature of this relationship. If a relationship for a given species was consistently reported to be significantly positive, negative, or non-significant, the species was marked by a positive (+) or negative (-) symbol or by NS. Species for which mixed results were reported in the literature, showing either non-significant/significantly positive relationships or non-significant/significantly negative relationships, were marked by NS/+ or NS/-, respectively. Colour intensity indicates values along a 1–4 scale of confidence to the support provided by each relationship pattern (+, -, NS, NS/+ and NS/-) to hypotheses (i–iii). Relationship A: a positive relationship predicted between female body size and clutch mass/clutch size (hypothesis i). Relationship B: a positive correlation predicted between the average offspring mass in a brood and female body mass (hypothesis ii). Relationship C: a negative correlation predicted between the mean mass of offspring and the number of offspring per brood (hypothesis iii).