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Coevolution between a cockroach and its bacterial endosymbiont: a biogeographical perspective
J W Clark1, S Hossain, C A Burnside
1Department of Entomology, Kansas State University, Manhattan 66506, USA.
Proceedings. Biological Sciences
|March 29, 2001
Summary
Molecular phylogenetics reveals Cryptocercus cockroaches colonized North America once and then split. Their ancient divergence aligns with geological events, explaining their current disjunct distribution.
Area of Science:
- Evolutionary Biology
- Molecular Phylogenetics
- Biogeography
Background:
- Cryptocercus are subsocial, wood-eating cockroaches with endosymbiotic bacteria.
- Disjunct populations exist in Eurasia and North America, with unclear evolutionary relationships.
- Limited understanding of the genus's biogeographical history and diversification.
Purpose of the Study:
- To infer the molecular phylogeny of Cryptocercus species and their endosymbionts.
- To investigate the evolutionary history and biogeographical patterns of the genus.
- To understand the causes behind the disjunct distribution of Cryptocercus.
Main Methods:
- Molecular phylogenetic analysis of six Cryptocercus species and their endosymbionts.
- DNA sequencing of endosymbiont genes.
- Divergence estimation using molecular clock methods.
Main Results:
- North American Cryptocercus form a monophyletic group, indicating a single colonization event followed by vicariance.
- Complete concordance observed between host and endosymbiont phylogenetic trees.
- Divergence estimates suggest palaearctic and nearctic species separated 70-115 million years ago; eastern and western USA species diverged 53-88 million years ago.
Conclusions:
- The findings support a single colonization of North America by Cryptocercus, followed by diversification.
- Endosymbiont divergence times correlate with major biogeographical events, explaining current distribution patterns.
- Cryptocercus exhibits a long evolutionary history, potentially originating in the Jurassic period.