RAPID LABORATORY EVOLUTION OF ADULT LIFE-HISTORY TRAITS IN DROSOPHILA MELANOGASTER IN RESPONSE TO TEMPERATURE.

Area of Science:

• Evolutionary Biology
• Environmental Adaptation
• Drosophila melanogaster Research

Background:

• Organisms evolve adaptations to their environments.
• Temperature is a critical environmental factor influencing biological processes.
• Long-term studies are crucial for understanding evolutionary trajectories.

Purpose of the Study:

• To investigate adaptation in Drosophila melanogaster to different thermal regimes.
• To assess changes in longevity, fecundity, and fertility following prolonged temperature selection.
• To explore the relationship between adaptation and population growth rates.

Main Methods:

• Culturing three replicate lines of Drosophila melanogaster at 16.5°C and 25°C for four years.
• Measuring lifespan, female fecundity, and fertility at both experimental temperatures.
• Calculating intrinsic rates of increase under varying population growth assumptions.

Main Results:

• Flies showed evidence of adaptation, with higher longevity and fecundity at their evolved temperature.
• Adaptation differences diminished at higher population growth rates due to early adulthood similarity.
• Both low- and high-temperature adapted lines exhibited higher progeny production rates at the higher temperature.

Conclusions:

• Drosophila melanogaster lines independently evolved adaptations to their respective thermal regimes.
• Potential trade-offs between adaptation to different temperatures or effects of mutation pressure were observed.
• Environmental temperature significantly influences evolved life-history traits and performance.