Evolution of the carabid ground beetles.

Area of Science:

• Entomology
• Evolutionary Biology
• Molecular Phylogenetics

Background:

• Carabid ground beetles represent a diverse insect group with complex evolutionary histories.
• Understanding their phylogenetic relationships is crucial for reconstructing their diversification and biogeography.

Purpose of the Study:

• To elucidate the phylogenetic relationships of carabid ground beetles globally.
• To reconstruct the evolutionary history and habitat establishment of Japanese carabids using molecular data.
• To investigate the tempo and mode of carabid evolution, including periods of rapid change and stasis.

Main Methods:

• Phylogenetic analysis of a large portion of the ND5 gene from over 1,000 carabid specimens.
• Mitochondrial DNA (mtDNA)-based molecular dating to estimate divergence times.
• Comparative analysis of molecular phylogenetics with morphological evolution.

Main Results:

• Established phylogenetic relationships for a comprehensive sample of global carabid genera and subgenera.
• Dated major carabid diversification events to approximately 40 million years ago (MYA), characterized by explosive radiation.
• Identified periods of rapid morphological change interspersed with evolutionary silent phases, indicating discontinuous evolution.
• Reconstructed a scenario for the establishment of Japanese carabid habitats based on phylogenetic insights.

Conclusions:

• Carabid evolution is characterized by discontinuous bursts of diversification and stasis.
• Major radiations around 40 MYA significantly shaped the current distribution and diversity of carabids.
• Parallel morphological evolution occurred in both closely and distantly related lineages during diversification events.