Fig. 2.

Hormonal and metabolic divergence among species across developmental stages. a Whole-body corticosterone (CORT) content was measured at the initiation of metamorphosis (Gosner stage 35), mid-metamorphosis (Gosner stage 38), and climax of metamorphosis (Gosner stage 42) for each spadefoot toad species under high water volume conditions. CORT contents were maximal and similar at metamorphic climax among species, but S. couchii had high, invariant CORT contents throughout the larval period unlike its relatives with longer and more plastic larval periods. b Size-corrected standard metabolic rate (SMR) was determined across the same developmental stages among species. SMR was fairly constant across development for each species, but the fastest developing species, S. couchii, showed the highest SMR, whereas the slowest developing species, P. cultripes, had the lowest SMR and S. multiplicata had an intermediate SMR. Sample sizes were 9, 11, and 10 for P. cultripes, 10, 10, and 9 for S. multiplicata, and 9, 5, and 8 for S. couchii at Gosner stages 35, 38, and 42