Chipmunk Evolutionary Biology

I have been working on a truly fascinating and diverse group of mammals—western chipmunks—over the last 20 years. There are 23 species and extensive diversity within each species. The research has focused on many aspects of their evolutionary biology through extensive fieldwork, genetics and genomics, morphology, and parasites. This has included unraveling phylogenetic relationships among the 23 species, identifying potentially new species, examining the phylogeography of individual species, assessing hybridization between some of the species, investigating genital bone diversity and evolution, understanding co-divergence of chipmunks and some of their parasites (sucking lice, nematodes), learning more about their basic natural history and distribution, and recently, exploring the possibility of phylosymbiosis (similarity between microbiomes mirrors the evolutionary relatedness of the hosts) in chipmunks. None of this would have been possible without the efforts of my long-term collaborators and their students, including Jack Sullivan (University of Idaho), Jeff Good (University of Montana), Kayce Bell (Natural History Museum of Los Angeles County), and funding from the Denver Museum of Nature & Science and the National Science Foundation (#0716200).


Sarver B. A. J., N. D. Herrera, D. Sneddon, S. L. Hunter, M. L. Settles, Z. Kroneneberg, J. R. Demboski, J. M. Good, and J. Sullivan (2021) Diversification, Introgression, and Rampant Cytonuclear Discordance in Rocky Mountains Chipmunks (Sciuridae: Tamias).Systematic Biology.

Bell K. C., J. M. Allen, K. P. Johnson, J. R. Demboski, and J. A. Cook. 2020. Disentangling lousy relationships: comparative phylogenomics of two sucking louse lineages parasitizing chipmunks. Molecular Phylogenetics and Evolution. 10.1016/j.ympev.2020.106998

Grond, K., K. C. Bell, J. R. Demboski, M. Santos, J. Sullivan, and S. M. Hird. 2019. No evidence for phylosymbiosis in western chipmunk species. FEMS Microbiology Ecology. fiz182. DOI: 10.1093/femsec/fiz182.

Bell, K. C., J. R. Demboski, and J. A. Cook. 2018. Sympatric parasites have similar host-associated, but asynchronous, patterns of diversification. American Naturalist 192(3):E106–E119. DOI: 10.1086/698300

Pigage, H. K., J. C. Pigage, and J. R. Demboski. 2017. Siphonaptera of North American western chipmunks. Comparative Parasitology 84(2):135–141. DIO: 10.1654/1525-2647-84.2.135

Sarver, B. A. J., J. R. Demboski, J. M. Good, N. Forshee, S. L. Hunter, and J. Sullivan. 2017. Comparative phylogenomic assessment of mitochondrial introgression among several species of chipmunks (Tamias). Genome Biology and Evolution 9(1):7–19. DOI: 10.1093/gbe/evw254

Bell, K. C., K. Calhoun, E. P. Hoberg, J. R. Demboski, and J. A. Cook. 2016. Temporal and spatial mosaics: deep host association and shallow geographic drivers shape genetic structure in a widespread pinworm, Rauschtineria eutamii (Nematoda: Oxyuridae). Biological Journal of the Linnean Society 119(2):397–413. DOI: 10.1111/bij.12833

Bell, K. C., D. Matek, J. R. Demboski, and J. A. Cook. 2015. Expanded host range of sucking lice and pinworms in Western North American chipmunks. Comparative Parasitology 82(2):312–321. DOI: 10.1654/4756.1

Sullivan, J., J. R. Demboski, K. C. Bell, S. Hird, B. Sarver, N. Reid, and J. M. Good. 2014. Divergence with gene flow within the recent chipmunk radiation (Tamias). Heredity 113(3):185–194. DOI: 10.1038/hdy.2014.27

Reid, N., J. R. Demboski, and J. Sullivan. 2012. Phylogeny estimation of the radiation of Western North American chipmunks (Tamias) in the face of introgression using reproductive protein genes. Systematic Biology 61(1):44–62. DOI: 10.1093/sysbio/syr094

Hird, S., N. Reid, J. Demboski, and J. Sullivan. 2010. Introgression at differentially aged hybrid zones in red-tailed chipmunks. Genetica 138(8):869–883. DOI: 10.1007/s10709-010-9470-z

Good, J. M., S. Hird, N. Reid, J. R. Demboski, S. J. Steppan, T. R. Martin-Nims, and J. Sullivan. 2008. Ancient hybridization and mitochondrial capture between two species of chipmunks (Tamias: Rodentia). Molecular Ecology 17(5):1313–1327. DOI: 10.1111/j.1365-294X.2007.03640.x

Good, J. M., J. R. Demboski, D. W. Nagorsen, and J. Sullivan. 2003. Phylogeography and introgressive hybridization: chipmunks (genus Tamias) in the northern Rocky Mountains. Evolution 57(8):1900–1916. DOI: 10.1111/j.0014-3820.2003.tb00597.x.

Demboski, J. R., and J. M. Sullivan. 2003. Extensive mtDNA variation within the yellow-pine chipmunk, Tamias amoenus (Rodentia: Sciuridae), and phylogeographic inferences for northwest North America. Molecular Phylogenetics and Evolution 26(3):389–408. DOI: 10.1016/S1055-7903(02)00363-9


John R. Demboski, PhD

Senior Curator of Mammals and Director of Zoology and Health Sciences

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