Physiology and acclimation potential are tuned with phenology in larvae of a prolonged breeder amphibian

Due to the speed of climate changes, rapid buffering mechanisms such as
phenotypic plasticity – which may depend on breeding phenology – could be
key to avoid extinction. The links between phenology and plasticity,
however, remain understudied. Here we explored the matching between
phenology and the thermal sensitivity of standard (SMR) and routine
metabolic rates (RMR), metabolic scope (i.e. the difference between RMR
and SMR), survival and growth-development trajectories in larvae of a
prolonged breeder amphibian (Alytes almogavarii) acclimated to 10 and
20ºC, belonging to three cohorts: autumn pre-overwintering, autumn
overwintering and spring tadpoles. At 20ºC, survival of autumn
pre-overwintering larvae was lower than for the rest. Although all cohorts
showed acclimation potential, patterns for SMR and RMR differed, leading
to differences in metabolic scope. Regardless of temperature,
overwintering tadpoles arrested growth and development, while
pre-overwintering and spring tadpoles showed higher growth and development
at 20ºC. At 10ºC pre-overwintering tadpoles allocated more energy to
development compared to spring tadpoles to advance development before
winter. Overall, we demonstrate that the effects of temperature depend on
phenology, consistent with future, expected thermal regimes. This suggests
that extreme events can yield different vulnerability to climate change
within populations (e.g., associated to discrete within-year cohorts), and
not only between species or populations.