Estradiol predicts pausing during mate-choice updating in a stress-buffered treefrog

Acute environmental stressors elevate circulating glucocorticoids on timescales of minutes to hours, raising the question of whether transient hypothalamic-pituitary-adrenal/interrenal (HPA) activation disrupts reproductive function during the brief breeding windows of seasonally breeding vertebrates. The conventional HPA-HPG crosstalk model predicts glucocorticoid-induced suppression of gonadal hormones and reproductive behavior, but seasonal breeders such as many frogs may be buffered against acute glucocorticoid elevation during peak reproductive readiness. Using an experimental cohort of Cope's gray treefrogs (Hyla chrysoscelis), we measured plasma 17β-estradiol (E₂) and tested a primary prediction of the buffering hypothesis: that acute corticosterone (CORT) manipulation will not suppress circulating E₂. We then explored whether endogenous E₂ covaried with mate-choice behavior in unmanipulated control females. Acute CORT manipulation did not alter circulating E₂, even at doses that increased plasma CORT by an order of magnitude, supporting the buffering hypothesis. Exploratory analyses revealed two complementary patterns: endogenous E₂ did not predict broad outcomes of mate choice (sexual proceptivity, locomotor effort, choice reversal probability, or initial preference for longer calls), but was positively associated with the duration of pauses made specifically at moments of decision reversal. Together, these findings support buffering of the female HPG axis against acute HPA activation during reproductive readiness while identifying decision deliberation as a fine-grained behavioral dimension that retains hormonal sensitivity during peak reproductive readiness.