Evidence from multiple gene sequences indicates that termites evolved from wood-feeding cockroaches

Area of Science:

• Evolutionary Biology
• Insect Phylogenetics
• Molecular Systematics

Background:

• The evolutionary origin of termites and their sister group remains a significant unresolved question in insect evolution.
• Understanding termite ancestry is key to explaining the evolution of eusociality, especially given their unique genetic system.
• Termites, cockroaches, and mantids belong to the order Dictyoptera, a group with complex and conflicting phylogenetic histories.

Purpose of the Study:

• To resolve the phylogenetic debate concerning the sister-group relationship of termites.
• To provide a robust evolutionary framework for understanding the development of eusociality in termites.

Main Methods:

• Sequencing of 18S ribosomal RNA, mitochondrial cytochrome oxidase subunit II (COII), and endogenous endo-beta-1,4-glucanase (EG) genes.
• Phylogenetic analyses using maximum parsimony and likelihood methods on diverse Dictyoptera taxa.

Main Results:

• Strong phylogenetic support for a clade comprising termites and the subsocial, wood-feeding cockroach genus Cryptocercus.
• This termite-Cryptocercus clade is nested within a broader cockroach clade.
• Wood-feeding cockroaches are implicated as evolutionary intermediates linking non-social ancestors to eusocial termites.

Conclusions:

• The study resolves the long-standing debate on termite ancestry.
• Subsocial wood-feeding cockroaches represent a crucial evolutionary link in the transition to termite eusociality.
• This provides a new model for understanding the evolution of complex social systems in insects.