Convergent Molecular Evolution Associated With Repeated Transitions to Gregarious Larval Behavior in Heliconiini

Area of Science:

• Evolutionary biology
• Genomics
• Animal behavior

Background:

• Collective behavior, particularly antipredator strategies, is crucial in nature.
• Larval gregariousness has evolved multiple times in Lepidoptera, but the genetic mechanisms are poorly understood.
• Social living imposes unique selection pressures on genome evolution.

Purpose of the Study:

• To investigate the molecular basis of repeated convergent evolution of gregarious larvae in Neotropical butterflies (Heliconiini).
• To explore genomic changes, including coding and noncoding DNA, and gene expression in social evolution.
• To identify candidate genes and pathways associated with the transition to gregarious behavior.

Main Methods:

• Comparative genomics across over 60 Heliconiini butterfly species.
• Analysis of differential selection on homologous genes and accelerated evolution in noncoding regions.
• Transcriptomic analysis of larval brains from solitary and gregarious species.

Main Results:

• Strong signatures of convergent molecular evolution detected in both coding and noncoding genomic regions of gregarious lineages.
• Evidence of convergent gene regulation in the brains of gregarious larvae at the transcriptomic level.
• Identification of candidate genes related to neural activity, feeding, and immunity under convergent selection.

Conclusions:

• Social living significantly alters selection pressures, leading to convergent genomic and transcriptomic changes.
• Repeated evolution of gregariousness in Heliconiini is underpinned by similar molecular mechanisms.
• These findings highlight the profound impact of sociality on genome evolution and trait development.