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Characterizing how organisms respond to transient temperatures may further our understanding of their susceptibility to climate change. Past studies in the freshwater turtle,Trachemys scripta, have demonstrated that the timing and duration of heat waves can have major implications for the response of genes involved in gonadal development and the production of female hatchlings. Yet, no study has considered how the response of these genes to transient cold snap exposure may affect gonadal development and the production of males. We investigated how cold snap timing affects gonadal gene expression inT. scriptaembryos and how the duration of an early cold snap influences the resulting hatchling sex ratios. Results show that responsiveness to cold changes rapidly across development, such that genes that responded when exposure began on incubation day 14 responded differently when exposure occurred just four or eight days later. Sex ratio data revealed that embryos experiencing an early cold snap also require a long exposure (>20 days) before most commit to testis development, suggesting that warm baseline temperatures may lower their sensitivity to later cold snap exposures. These results highlight how individual responses to incubation temperature can change rapidly across development in turtles and have important effects on sex ratios.
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This content will become publicly available on December 1, 2025
Shell shape does not accurately predict self-righting ability in hatchling freshwater turtles
Abstract Flat hydrodynamic shells likely represent an evolutionary trade-off between adaptation to an aquatic lifestyle and the instability of more rounded shells, thought beneficial for self-righting. Trade-offs often result in compromises, this is particularly true when freshwater turtles, with flatter shells, must self-right to avoid the negative effects of inverting. These turtles, theoretically, invest more biomechanical effort to achieve successful and timely self-righting when compared to turtles with rounded carapaces. This increase in effort places these hatchlings in a precarious position; prone to inversion and predation and with shells seemingly maladapted to the act of self-righting. Here, we examine hatchling self-righting performance in three morphologically distinct freshwater turtle species (Apalone spinifera,Chelydra serpentinaandTrachemys scripta scripta) that inhabit similar environmental niches. We demonstrate that these hatchlings were capable of rapid self-righting and used considerably less biomechanical effort relative to adult turtles. Despite differences in shell morphology the energetic efficiency of self-righting remained remarkably low and uniform between the three species. Our results confound theoretical predictions of self-righting ability based on shell shape metrics and indicate that other morphological characteristics like neck or tail morphology and shell material properties must be considered to better understand the biomechanical nuances of Testudine self-righting.
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- Award ID(s):
- 1755187
- PAR ID:
- 10502213
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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