Natural selection mediated by seasonal time constraints increases the alignment between evolvability and...

Area of Science:

• Evolutionary biology
• Ecology
• Genetics

Background:

• Phenotypic plasticity can influence adaptation to new environments, potentially constraining or promoting evolutionary change.
• Previous research suggested that alignments between plasticity, genetic variation, and divergence might indicate evolutionary constraints.
• This study re-evaluates the role of natural selection in shaping these evolutionary alignments.

Purpose of the Study:

• To investigate whether natural selection shapes the alignment between developmental plasticity, genetic variation, and evolutionary divergence.
• To determine the effects of latitude, photoperiod, and environmental novelty on genetic covariance matrices (G) and their alignment with adaptive plasticity.
• To test if observed alignments reflect constraints or are a result of adaptive evolutionary processes.

Main Methods:

• Estimating developmental plasticity and broad-sense genetic covariance matrices (G) in damselfly populations across a European latitudinal gradient.
• Rearing damselflies under simulated northern (strong seasonal constraints) and southern (relaxed constraints) photoperiods.
• Partitioning the influence of latitude, photoperiod, and environmental novelty on G and its alignment with plasticity and divergence.

Main Results:

• Environmental novelty and latitude did not significantly alter G.
• Photoperiod significantly affected G, increasing evolvability in damselflies.
• Under strong seasonal time constraints (northern photoperiod), G aligned with adaptive divergence and developmental plasticity.

Conclusions:

• The alignment between genetic variation, plasticity, and divergence is shaped by natural selection, not necessarily by evolutionary constraints.
• Seasonal time constraints, simulated by photoperiod, play a crucial role in driving these adaptive evolutionary alignments.
• These findings suggest that natural selection actively molds the evolutionary potential and direction in response to environmental pressures.