Pattern of geographic distribution of abundance (upper panel), size (middle panel) and sex ratio (lower panel) for the two species of sandhoppers (top of the figure).

The range is reported as Range Index (see Material and Methods), where −1 =  southern/eastern range; 0 =  centre; +1 =  northern/western range. The model which best fitted the observed is reported as a small icon for each pattern of distribution. The IQ model (see Material and Methods) is referred to the female size distribution. Ra = relative abundance; RS = relative size; filled dots: males; open dots: females.