Density dependence, lifespan and the evolutionary dynamics of longevity

Area of Science:

• Evolutionary Biology
• Population Genetics
• Theoretical Ecology

Background:

• Longevity is a key life-history trait shaped by natural selection.
• Current evolutionary analyses of longevity primarily use density-independent frameworks (e.g., Euler-Lotka).
• The impact of density dependence on lifespan evolution remains under-explored.

Purpose of the Study:

• To investigate how diverse population demographies influence the evolution of longevity.
• To explore the link between density-dependent longevity evolution and adaptive radiations.
• To analyze the effects of mutation characteristics on fitness, invasion, and diversification.

Main Methods:

• Development and analysis of a range of theoretical models.
• Exploration of intraspecific and interspecific density effects on longevity.
• Modeling the influence of mutation magnitude, type, and timing.

Main Results:

• Density dependence significantly impacts the evolution of lifespan and mortality trajectories.
• Demographic structures, mutation properties, and density effects influence diversification.
• Alternative evolutionary strategies under varying demographics result in flat fitness landscapes.

Conclusions:

• Density-dependent factors are critical for a comprehensive understanding of longevity evolution.
• Flat fitness landscapes, arising from specific demographic structures, are important for lifespan evolution and senescence.
• This framework provides new insights into adaptive radiations and diversification processes.