Phylogenetic analyses of termite post-embryonic sequences illuminate caste and developmental pathway evolution

Area of Science:

• Evolutionary biology
• Insect behavior
• Molecular phylogenetics

Background:

• Termites exhibit caste polyphenism, with distinct developmental pathways leading to specialized roles.
• The evolutionary origins of these developmental pathways and caste systems remain largely unknown.
• Recent phylogenetic studies suggest independent evolution of sterile castes in termites.

Purpose of the Study:

• To investigate the evolutionary origins of caste polyphenism in termites.
• To determine if diploid sterile castes evolved multiple times independently.
• To explore the evolution of developmental flexibility in termite workers.

Main Methods:

• Phylogenetic analysis of molecular data.
• Comparative analysis of developmental pathways across termite lineages.
• Reconstruction of ancestral states for caste evolution.

Main Results:

• Diploid sterile castes (true workers) evolved independently multiple times in termites.
• At least one lineage experienced a loss of sterile castes, developing flexible pseudergates (false workers).
• Developmental plasticity in post-embryonic development evolved independently multiple times.

Conclusions:

• The evolution of termite caste polyphenism is characterized by multiple independent origins and losses of sterile castes.
• Developmental flexibility in worker pathways is a recurrent evolutionary innovation in termites.
• Detailed analysis of developmental pathways is crucial for understanding the macroevolution of termite sociality.