Note that while the body-size classes of C. maenas used in this experiment probably represent different ontogenetic stages in their growth, gut content analysis carried out on the crabs at the end of the experiment suggests that the taxonomic composition of the diet was largely similar across the size classes (see electronic supplementary material, table S1). Instead, the variation in C. maenas body size determines the optimal foraging niche, with different taxonomic groups representing a greater proportion of the diet for different size classes of crabs (most likely related to strength of the chelae, mobility and intimidating presence).