Strong artificial selection in the wild results in predicted small evolutionary change

Area of Science:

• Evolutionary biology
• Quantitative genetics
• Ecology

Background:

• Estimating genetic variation and selection aids evolutionary predictions in lab settings.
• Natural populations present complexities, where selection on heritable traits may not yield phenotypic change.

Purpose of the Study:

• To assess the predictability of evolutionary dynamics for a complex trait in a natural environment.
• To investigate evolutionary change in clutch size in a wild population of great tits (Parus major) over eight years.

Main Methods:

• Conducted a two-way selection experiment on clutch size.
• Utilized a statistical model to infer genetic changes in clutch size.
• Studied a subdivided island population of great tits (Parus major).

Main Results:

• Despite strong artificial selection, no clear phenotypic evolutionary change in clutch size was observed.
• Environmentally induced annual variations in clutch size were substantial, potentially masking evolutionary shifts.
• Inferred genetic changes in clutch size aligned with predictions from statistical models.

Conclusions:

• Genetic variation and selection estimates can quantitatively predict evolutionary change, even in wild populations.
• Demonstrating evolution in natural populations is difficult due to environmental influences.
• Careful interpretation of phenotypic trends is crucial when studying wild populations.