Colour change and mimicry from juvenile to adult:: Xantho poressa (Olivi, 1792) (Brachyura, Xanthidae) and Carcinus Maenas (Linnaeus, 1758) (Brachyura, Portunidae)

For two years we have studied carapace colour change, mimicry, and substrate choice during the juvenile stages of two species of crabs, Xantho poressa and Carcinus maenas, Both species live in the Posidonia oceanica meadows until their last moult, after which they abandon the prairies for the nearest rocky substrate (Xantho) or for soft sea bottoms (Carcinus).