Extreme developmental instability associated with wing plasticity in pea aphids.

Area of Science:

• Evolutionary developmental biology
• Phenotypic diversity
• Genetics

Background:

• Phenotypic variation arises from plasticity and developmental instability in genetically identical individuals.
• The interplay between plasticity, developmental instability, and their fitness consequences remains largely unknown.
• Asymmetric phenotypes offer a unique model to investigate these relationships.

Purpose of the Study:

• To investigate the connection between plasticity, developmental instability, and fitness using an asymmetric wing development in pea aphids.
• To determine the nature of this asymmetry, its genetic basis, and its impact on reproductive success.

Main Methods:

• Observation and analysis of asymmetric wing development in pea aphid lines.
• Assessment of the occurrence of asymmetry on both sides to identify developmental instability.
• Evaluation of fecundity levels in aphids exhibiting asymmetric wing development.

Main Results:

• Asymmetric wing development in pea aphids was identified as a developmental instability, occurring equally on both sides.
• The trait demonstrated a genetic basis, present in some lines but not others.
• Aphids with asymmetric wings exhibited intermediate fecundity, indicating no significant fitness cost.

Conclusions:

• Dramatic asymmetry in pea aphids may result from incomplete switching between developmental targets, linking plasticity and developmental instability.
• This phenomenon could be widespread in species with distinct, alternative phenotypes.
• Developmental instability does not always correlate with negative fitness outcomes.