Data from: Stress hormones mediate predator-induced phenotypic plasticity in amphibian tadpoles

Amphibian tadpoles display extensive anti-predator phenotypic plasticity,
reducing locomotory activity and, with chronic predator exposure,
developing relatively smaller trunks and larger tails. In many
vertebrates, predator exposure alters activity of the neuroendocrine
stress axis. We investigated predator-induced effects on stress hormone
production and the mechanistic link to anti-predator defences in Rana
sylvatica tadpoles. Whole-body corticosterone (CORT) content was
positively correlated with predator biomass in natural ponds. Exposure to
caged predators in mesocosms caused a reduction in CORT by 4 hours, but
increased CORT after 4 days. Tadpoles chronically exposed to exogenous
CORT developed larger tails relative to their trunks, matching
morphological changes induced by predator chemical cue; this predator
effect was blocked by the corticosteroid biosynthesis inhibitor
metyrapone. Tadpole tail explants treated in vitro with CORT increased
tissue weight, suggesting that CORT acts directly on the tail. Short-term
treatment of tadpoles with CORT increased predation mortality, likely due
to increased locomotory activity. However, long-term CORT treatment
enhanced survivorship, likely due to induced morphology. Our findings
support the hypothesis that tadpole physiological and
behavioural/morphological responses to predation are causally
interrelated. Tadpoles initially suppress CORT and behaviour to avoid
capture, but increase CORT with longer exposure, inducing adaptive
phenotypic changes.