Sex-specific shifts in morphology and diet in a frog after 50 years of anthropogenic habitat fragmentation

Aim: Phenotypic shifts are commonly observed when animals face insular habitat change and may reflect ongoing stresses on individuals. However, the generality and the driving processes of this ‘island rule’ remain equivocal, notably in amphibians. Here, we investigate both morphological and dietary shifts in a frog using a mosaic of human-created islands to assess the potential operating mechanisms underlying these phenotypic responses.
Location: Thousand Island Lake, China.
Taxon: The Chinese piebald odorous frog, Odorrana schmackeri.
Results: We found insular dwarfism in female but not male frogs. Meanwhile, insular females also had smaller gape widths after accounting for snout-vent lengths (SVLs) than mainland females. According to SEMs, resource availability had a direct positive effect on body size. Finally, diet composition differed between island and mainland populations, but only in females. Males and females on islands exhibited greater overlaps in diet.
Main conclusions: In c...