Founders predict trait evolution and population performance after evolutionary rescue in the red flour beetle

Area of Science:

• Evolutionary biology
• Population genetics
• Ecology

Background:

• Evolutionary rescue is crucial for species survival amid environmental change.
• Understanding factors influencing rescue dynamics and long-term outcomes is vital.
• Phenotypic and demographic traits' roles in evolutionary rescue are not fully understood.

Purpose of the Study:

• To investigate phenotypic and demographic factors driving evolutionary rescue in flour beetles.
• To assess the long-term effects of evolutionary rescue on population performance.
• To identify predictors of successful adaptation and population persistence.

Main Methods:

• Experimentally evolved 10 wild flour beetle populations on a suboptimal corn resource for 70 generations.
• Collected over 10,000 population census data points.
• Measured fitness-related traits of 30 experimental lines before and after evolution.

Main Results:

• All populations exhibited parallel evolutionary rescue within 20 generations, despite varied ancestral traits.
• Ancestral development rate positively correlated with long-term average population size.
• Convergent increase in development rate across populations predicted performance during and after rescue.
• Demographic events during rescue did not correlate with ancestral traits or post-rescue adaptation.

Conclusions:

• Founder traits, particularly development rate, are key predictors of adaptation and long-term success in evolutionary rescue.
• Convergent evolution of development rate facilitated population performance.
• Specific demographic trajectories during rescue are not reliable indicators of long-term adaptation.