Butterfly eyespot patterns and how evolutionary tinkering yields diversity.

Area of Science:

• Evolutionary Biology
• Developmental Genetics (Evo-Devo)
• Animal Systematics

Background:

• Eyespots are recurring wing patterns in butterflies, crucial for species recognition and defense.
• The genus Bicyclus exhibits conserved eyespot developmental processes across its diverse species.
• Understanding the genetic and developmental basis of eyespot variation is key to explaining butterfly diversity.

Purpose of the Study:

• To investigate the flexibility of butterfly eyespot evolution under artificial selection.
• To compare the evolvability of eyespot size versus eyespot color composition.
• To link genetic and developmental mechanisms to observed patterns of diversity in Bicyclus butterflies.

Main Methods:

• Artificial selection experiments on Bicyclus anynana butterfly eyespot size and color.
• Quantification of phenotypic variation and response to selection over 25 generations.
• Comparative analysis of developmental regulation and genetic variation for different eyespot traits.

Main Results:

• Eyespot size demonstrated high evolvability, with selection yielding phenotypes beyond natural variation.
• Eyespot color composition showed limited flexibility, primarily evolving along a constrained 'axis of least resistance'.
• Significant differences in developmental regulation and genetic variation underlie the distinct evolvability of size and color.

Conclusions:

• Evolvability of butterfly eyespots is trait-dependent, with size being more labile than color.
• Developmental constraints and genetic architecture differentially influence the evolutionary trajectories of morphological traits.
• Understanding trait-specific evolvability is critical for explaining macroevolutionary patterns and biodiversity.