Long-term evolution experiments fully reveal the potential for thermal adaptation.

Area of Science:

• Evolutionary biology
• Climate change adaptation
• Environmental science

Background:

• Organisms must adapt to climate change, but understanding evolutionary dynamics in warming environments remains incomplete.
• Reproductive success is a key trait constrained by temperature, making its evolution under warming critical.
• Experimental evolution offers insights into population responses to environmental change, yet long-term studies are scarce.

Purpose of the Study:

• To investigate the long-term thermal adaptation of Drosophila subobscura populations.
• To assess the evolution of reproductive success under sustained warming conditions.
• To compare adaptive responses between populations with different geographic origins.

Main Methods:

• Utilized experimental evolution with two Drosophila subobscura populations from different European latitudes.
• Exposed populations to a warming environment for approximately 50 generations.
• Assessed reproductive success in both ancestral (control) and warming environments.

Main Results:

• Observed a general long-term adaptive response to warming temperatures.
• Populations evolved in warming conditions showed improved performance in that environment compared to controls.
• No significant adaptive response was detected in the ancestral environment.
• Highlighted a slow pace of adaptation and inter-population variation in responses.

Conclusions:

• Long-term evolution experiments are essential for fully understanding thermal adaptation potential.
• Variation in evolutionary responses necessitates studying multiple populations across space and time.
• Robust assessments of climate change impacts require accounting for both temporal and spatial variation in evolutionary responses.