Cross-Generational Effects of Stress on Captive Adults and Their Released Offspring in an Amphibian
Ex situ conservation, translocation, and reintroduction are becoming increasingly important for species restoration. In amphibians, however, effects of captive stress on adults and subsequent effects on their offspring that are later reintroduced into the wild are largely unknown. Using Fowler's toads (Anaxyrus fowleri) as a model species, we investigated effects of increased captive stress on corticosterone (CORT) concentration in adult toads. We then examined CORT levels in their tadpole offspring, which we reared in natural ponds to simulate conditions of a reintroduced population. We found no significant effects of captive stress on adult or offspring CORT levels. However, despite poor model performance due to low sample size, baseline CORT of sires (but not dams) was the best predictor of, and negatively correlated with, baseline CORT and change in CORT in offspring. Our study provides a unique perspective on the potential translation of stress from parent to offspring and points to a need for a closer examination of paternal effects in cases of cross-generational studies in amphibians.Abstract
Diagram of experimental design with waterborne hormone collection. Adult Anaxyrus fowleri were split into experimental and control groups, with and without restrictive stress treatment, respectively (A). Tadpoles from all groups underwent the same process for sample collection (B).
Comparisons of adult Anaxyrus fowleri in control and restrictive stress treatment groups. Boxplots overlaid on violin plots of ΔCORT, corrected by SVL (A). Violin plots of female fertility, calculated as number of eggs laid per female, corrected by SVL (B). Violin plots of male fertility, calculated as percentage of clutch fertilized per male (C).
Relative importance of covariates in predicting two Anaxyrus fowleri tadpole dependent variables (A, C) and corresponding relationships between dependent variables and their top predictor (B, D). Maroon numbers on the bar charts indicate model performance.
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