Understanding the keys to thermal adaptation in populations along latitudinal gradients
Ignacio Peralta-Maraver, a postdoctoral researcher in the Department of Ecology and a member of Modeling Nature, has co-led a novel study with researchers from Pontificia Universidad Católica de Chile and Universidad Autónoma de Barcelona. The study, which tackles adaptation to global warming, has been published in the Proceedings of the Royal Society B, the UK Royal Society's flagship biological research journal.
Currently, in the realm of ecophysiology, two primary hypotheses exist to comprehend how organisms adapt to global warming (Figure 1). The first hypothesis, known as "warmer-is-better," infers that thermodynamic limitations dictate the ability to adapt to extreme temperatures. This hypothesis anticipates a pivotal result: populations acclimatized to heat will exhibit superior performance (fitness) within their optimal temperature ranges, unlike populations that have adapted to cold conditions. The second hypothesis, termed "jack-of-all-temperatures," proposes that biochemical adaptations facilitate the management of thermal stress. Here, regardless of their thermal preferences, all populations are expected to demonstrate identical biological efficiency within their optimal temperature range.
This innovative study interweaves methodologies from ecology and physiology to examine the impacts of thermodynamic restrictions and biochemical adaptation on the biological efficacy of Drosophila simulans populations along Chile's latitudinal gradient. The findings disclose a pronounced latitudinal pattern in these populations' adaptation to heat. This pattern appears more as a consequence of thermodynamic limitations, while evolutionary forces only partially compensate for these constraints.
The investigators have also pinpointed a tight correlation between metabolism and survival, demonstrating that thermal adaptation transpires simultaneously across the levels of biological organization. Further, the study indicates that heat tolerance declines as we move toward the molecular level. These results support that thermal adaptation is an emergent feature tied to increased biological complexity (Figure 2).
This research provides a deeper insight into the repercussions of climate change on wildlife and forecasts how species might respond to future extreme conditions. The study emphasizes that laws of thermodynamics predominantly drive adaptation to increased temperatures, contingent on the geographical location of the populations.
Reference
Alruiz JM, Peralta-Maraver I, Bozinovic F, Santos M, Rezende EL. (2023).
Temperature adaptation and its impact on the shape of performance curves in Drosophila populations.
Proceedings of the Royal Society B. 290: 20230507.
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