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My research focuses on symbiosis, with a particular interest in the evolutionary and ecological consequences of associations between insects and heritable microorganisms. Inherited microbes, those that are transmitted vertically from mother to offspring, can spread within host populations by providing benefits to hosts. Defense against natural enemies is one of the most exciting, and potentially widespread, beneficial effects recently discovered in insect-symbiont associations. In this emerging area of inquiry there is much to discover about the dynamics and distributions of defensive symbionts in natural populations, the genetic features of defensive symbionts, including molecular mechanisms of protection, and the impacts these symbionts exert on populations and communities. This lab uses a multidisciplinary approach, incorporating field studies, experimental laboratory assays and microscopy, as well as molecular, genomic and proteomic tools to investigate symbiont-based defense across scales ranging from molecules to populations and communities.


Aphidius attacking pea aphids.Aphidius attacking pea aphids. Photograph by Alex Wild.

Lab Personnel

Kyungsun L. Kim, Research Professional II

Post-doctoral Associates

Dr. Vilas Patel

Graduate Students

Clesson Higashi (PhD Entomology)
Nicole Lynn-Bell (PhD Microbiology)
Suzanne Allison (ILS: PhD Entomology)

Former students

Stephanie Weldon (PhD completed 2015)      
Adam Martinez, (PhD completed 2015)
Matt Doremus (MS completed 2016)
Laura Kraft (BS/MS completed 2016) 
Hannah Dykstra (MS completed 2013)

Undergraduate Researchers

Bryan Kamalaker

Courses Taught

ENTO 4000/6000. General Entomology.
Functional anatomy and physiology, behavior, ecology, insects as vectors of pathogens, chemical and biological control of pests.
ENTO 8500. Insect Ecology.
Ecology of insects in natural and managed ecosystems.

Selected Publications (For full list see Google Scholar)

Doremus MR, Smith AR, Kim KL, Holder AJ, Russell JA & Oliver KM (2017). Breakdown of a defensive symbiosis, but not endogenous defenses, at elevated temperatures Molecular Ecology. In press.

Brandt JW, Chevignon G, Oliver KM & Strand MR (2017). Culture of an aphid symbiont demonstrates its direct role in defense against parasitoids. Proc. Royal Soc. Lon. Ser. B. In press.

Kraft LJ, Kopko J, Harmon JP & Oliver (2017). Aphid symbionts and endogenous resistance traits mediate competition mediate rival parasitoids. PlosOne. DOI:10.1371/journal.pone.0180729

Martinez AJ, Doremus MR, Kim KL & Oliver KM (2017). Multi-modal defenses in aphid offer redundant protection and increased costs likely impeding a protective mutualism. Journal of Animal Ecology. Epub 5 Jun DOI: 10.1111/1365-2656.12675

Doremus MR & Oliver KM (2017) Aphid heritable symbiont exploits defensive mutualism. Applied & Environmental Microbiology 83:8, doi:10.1128/AEM.03276-16

Martinez AJ, Kim KL, Harmon JP & Oliver KM (2016) Specificity of multi-modal aphid defenses against two rival parasitoids. PlosOne 11(5): e0154670.doi:10.1371/journal.pone.0154670

Oliver KM & Russell JA (2016). Symbiosis, an introduction to. Encyclopedia of Evolutionary Biology. Editor; R. Kliman. Elsevier.

Weldon SR & Oliver KM (2016). Diverse bacteriophage roles in an aphid defensive mutualism.

Advances in Environmental Microbiology. Editor: CJ. Hurst Volume: The Mechanistic Benefits of Microbial Symbionts. Springer, Berlin.

Oliver KM & Martinez AJ (2014). How resident microbes modulate ecologically-important traits of insects. Current Opinion in Insect Science. DOI:10.1016/j.cois.2014.08.001.

Dykstra HR, Weldon SR, Martinez AJ, White J, Hopper K, Heimpel, G, Asplen M, Oliver KM. (2014). Factors limiting the spread of the protective symbiont Hamiltonella defensa in the aphid Aphis craccivora. Applied and Environmental Microbiology. 80:18 doi:10.1128/AEM.01775-14.

Martinez AJ, Ritter SG, Doremus MR & Oliver KM (2014). Aphid-encoded variability in susceptibility to a parasitoid. BMC Evolutionary Biology 14: 127 doi:10.1186/1471-2148-14-127

Martinez AJ, Weldon SR & Oliver KM (2014). Effects of parasitism on aphid nutritional and
Protective symbioses. Molecular Ecology 23:6 1594-1607. doi: 10.1111/mec.12550.

Oliver KM & Russell JA (2013). Defensive symbiosis in the real world—framing studies on the diversity and maintenance of protective bacteria in natural insect populations. Functional Ecology. Published online June 2013: DOI: 10.1111/1365-2435.12133

Russell JA, Weldon S, Smith D, Kim KL, Hu Y, Lukasik P, Doll S, Anastopoulos I, Novin M, and Oliver KM (2013) Uncovering symbiont-driven genetic diversity across North American pea aphids. Molecular Ecology 22: 2045-2059.

Weldon SR, Strand MR & Oliver KM (2013). Phage loss and the breakdown of a defensive
symbiosis. Proceedings of the Royal Society London Series B. 280 (1751)

Oliver KM, Noge K, Huang EM, Campos JM, Becerra JX & Hunter MS (2012) Parasitic wasp responses to symbiont-based defense. BMC Biology 10:11

Oliver, K. M., Degnan, P. H., Burke, G. R. & Moran, N. A. 2010. Facultative symbionts of aphids and the horizontal transfer of ecologically important traits. Ann. Review of Entomology 55, 247–266.

Oliver, K. M., Degnan, P. H., Hunter, M.S. & Moran, N. A. 2009. Bacteriophages encode factors required for protection in a symbiotic mutualism. Science 325, 992-994.

Oliver, K. M. & Moran, N. A. 2009. Defensive symbionts in aphids and other insects in White, J. F. & Torres, M. S. Defensive mutualism in microbial symbiosis. London: Taylor & Francis.

Oliver, K. M., Campos, J., Moran, N. A. & Hunter, M. S. 2008. Population dynamics of defensive symbionts in aphids. Proceedings of the Royal Society of London Series B-Biological Sciences 275, 293-299.

Oliver, K. M., Moran, N. A. & Hunter, M. S. 2006. Costs and benefits of a superinfection of facultative symbionts in aphids. Proceedings of the Royal Society of London Series B-Biological Sciences 273, 1273-1280.

Oliver, K. M., Moran, N. A. & Hunter, M. S. 2005. Variation in resistance to parasitism in aphids is due to symbionts not host genotype. Proceedings of the National Academy of Sciences of the United States of America 102, 12795-12800.

Oliver, K. M., Russell, J. A., Moran, N. A. & Hunter, M. S. 2003. Facultative bacterial symbionts in aphids confer resistance to parasitic wasps. Proceedings of the National Academy of Sciences of the United States of America 100, 1803-1807.