Individually variable energy management during egg production is repeatable across breeding attempts.

Area of Science:

• Animal physiology
• Evolutionary biology
• Behavioral ecology

Background:

• Whole-animal metabolism, such as daily energy expenditure (DEE), is crucial for organismal fitness.
• Systematic relationships between DEE and individual traits, environment, or fitness are not well-established in birds and mammals.
• Reproductive metabolic demands may be met by individually variable energy management strategies in female birds.

Purpose of the Study:

• To investigate the repeatability of energy expenditure adjustments during reproduction in female birds.
• To determine if individual plasticity in energy expenditure is consistent across successive breeding attempts.
• To emphasize the significance of studying phenotypic plasticity in physiological and metabolic traits.

Main Methods:

• Longitudinal measurements of daily energy expenditure (DEE) in female zebra finches (Taeniopygia guttata).
• Assessment of energy expenditure changes associated with egg production across multiple breeding attempts.
• Analysis of individual repeatability in metabolic adjustments.

Main Results:

• Female zebra finches display individually repeatable plasticity in energy expenditure during egg production.
• These metabolic adjustments are consistent between successive breeding attempts within individuals.
• Energy management strategies during reproduction vary significantly among individuals.

Conclusions:

• Individually variable energy management strategies are a repeatable trait in female birds.
• Phenotypic plasticity in physiological and metabolic traits, like DEE, is important for reproductive success.
• Future research should incorporate plasticity into evolutionary studies of physiological traits.