Thermal limits along tropical elevational gradients: Poison frog tadpoles show plasticity but maintain divergence across elevation.

Autor: Páez-Vacas MI; Centro de Investigación en Biodiversidad y Cambio Climático (BioCamb), Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias del Medio Ambiente, Universidad Tecnológica Indoamérica, Av. Machala y Sabanilla, Quito, Ecuador; Biology Department, Colorado State University, Fort Collins, CO, USA; Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA; Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Jambatu, San Rafael, Quito, Ecuador. Electronic address: monicapaezv@gmail.com., Funk WC; Biology Department, Colorado State University, Fort Collins, CO, USA; Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA.
Jazyk: angličtina
Zdroj: Journal of thermal biology [J Therm Biol] 2024 Feb; Vol. 120, pp. 103815. Date of Electronic Publication: 2024 Feb 20.
DOI: 10.1016/j.jtherbio.2024.103815
Abstrakt: Temperature is arguably one of the most critical environmental factors impacting organisms at molecular, organismal, and ecological levels. Temperature variation across elevation may cause divergent selection in physiological critical thermal limits (CT MAX and CT MIN ). Generally, high elevation populations are predicted to withstand lower environmental temperatures than low elevation populations. Organisms can also exhibit phenotypic plasticity when temperature varies, although theory and empirical evidence suggest that tropical ectotherms have relatively limited ability to acclimate. To study the effect of temperature variation along elevational transects on thermal limits, we measured CT MAX and CT MIN of 934 tadpoles of a poison frog species, Epipedobates anthonyi, along two elevational gradients (200-1700 m asl) in southwestern Ecuador to investigate their thermal tolerance across elevation. We also tested if tadpoles could plastically shift their critical thermal limits in response to exposure to different temperatures representing the range of temperatures they experience in nature (20 °C, 24 °C, and 28 °C). Overall, we found that CT MAX did not change across elevation. In contrast, CT MIN was lower at higher elevations, suggesting that elevational variation in temperature influences this thermal trait. Moreover, all populations shifted their CT MAX and CT MIN according to treatment temperatures, demonstrating an acclimation response. Overall, trends in CT MIN among high, mid, and low elevation populations were maintained despite plastic responses to treatment temperature. These results demonstrate that, for tadpoles of E. anthonyi across tropical elevational gradients, temperature acts as a selective force for CT MIN , even when populations show acclimation abilities in both, CT MAX and CT MIN . Our findings advance our understanding on how environmental variation affects organisms' evolutionary trajectories and their abilities to persist in a changing climate in a tropical biodiversity hotspot.
Competing Interests: Declaration of competing interest The authors declare no competing or financial interests.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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