Ellen D. Ketterson is an American evolutionary biologist, behavioral ecologist, neuroendocrinologist and ornithologist best known for her experimental approach to the study of life-history trade-offs in a songbird, the Dark-eyed Junco. She is currently a Distinguished Professor of Biology, Director of the Environmental Resilience Institute, and affiliate professor in Cognitive Science, Gender Studies, Integrative Study of Animal Behavior, and Neuroscience at Indiana University.
After receiving her doctoral degree, Ketterson was a postdoctoral scholar from 1974 to 1975 at Washington State University working with avian environmental physiologist James R. King.[1] She was an assistant professor at Bowling Green State University from 1975 to 1977 before joining the faculty in the Department of Biology at Indiana University in 1977.[1] Ketterson was appointed as a Distinguished Professor of Biology at Indiana University in 2006. [1] She was also appointed as an affiliated faculty member of the Gender Studies department in 2003 and as a program faculty member of the Cognitive Science department in 2006 at Indiana University.[1]
Ketterson and her trainees, with her longtime collaborator and partner Val Nolan, Jr., have conducted long-term field studies combined with experimental manipulation of free-living dark-eyed juncos at the Mountain Lake Biological Station in Virginia since the 1970s.[7][8][9] Early in her career, Ketterson focused on differential migration, a pattern of movement in which females migrate farther than males.[10][11]
Ketterson developed the experimental approach of manipulating levels of the hormone testosterone in free-living birds and comparing behavior, physiology, and fitness to controls in order to study the evolution of life history trade-offs.[12][13][14] She coined the term ‘phenotypic engineering’ to describe this approach.[12][14] Ketterson's research showed that experimentally-elevated levels of testosterone increased male aggression, reduced parental care, and increased singing in males.[13] In addition, males given exogenous testosterone were preferred by females in mate choice tests.[15] They also exhibited higher reproductive success as a result of extra-pair fertilizations despite lower success of broods that they parent.[16] However, she also found that testosterone-treated males had shorter life spans[13] and reduced immune system function.[17] Her research has provided a mechanistic understanding of the fitness consequences of how animals allocate time and energy to competing demands (i.e. reproduction versus survival).
Later, her work explored whether hormones, which affect multiple target tissues simultaneously and mediate coordinated suites of traits, either constrain or potentiate adaptation.[18][19] This work foreshadowed her interest in addressing limits to organisms' ability to respond to environmental change and the role of hormonally-mediated seasonal timing of behaviors (like reproduction, molt, and migration) in the generation and loss of biodiversity. As the director of the Environmental Resilience Institute, she leads a team of Indiana University researchers to prepare the Hoosier state for the effects of on-going environmental change.[20]
Kimmitt, A.A., Sinkiewicz, D.M., Ketterson E.D. (2020). Seasonally sympatric songbirds that differ in migratory strategy also differ in neuroendocrine measures. General and Comparative Endocrinology 285, 113250.
Whittaker, D.J., Slowinski, S.P., Greenberg, J.P., Alian O., Winters A.D., Ahmad M.M., Burrell M.J.E., Soini H.A., Novotny M.V., Ketterson, E.D., Theis, K.R. (2019). Experimental evidence that symbiotic bacteria produce chemical cues in a songbird. Journal of Experimental Biology 222 (20), jeb202978.
Kimmitt, A.A., Hardman, J.W., Stricker, C.A., Ketterson, E.D. (2019). Migratory strategy explains differences in timing of female reproductive development in seasonally sympatric songbirds. Functional Ecology 33 (9), 1651–1662.
Reed, S.M., Ketterson, E.D. (2019). Breeding Latitude and Annual Cycle Timing in a Songbird. IU Journal of Undergraduate Research.
Liebgold, E.B., Gerlach, N.M., Ketterson, E.D. (2019). Density‐dependent fitness, not dispersal movements, drives temporal variation in spatial genetic structure in dark‐eyed juncos (Junco hyemalis). Molecular Ecology 28 (5), 968–979.
Singh, D., Reed, S.R., Kimmitt, A.A., Alford, K.A., Ketterson, E.D. (2019). Breeding at higher latitude as measured by stable isotope is associated with higher photoperiod threshold and delayed reproductive development in a songbird. bioRxiv, 789008.
Reichard, D.G., Atwell, J.W., Pandit, M.M., Cardoso, G.C., Price, T.D., Ketterson, E.D. (2019). Urban birdsongs: higher minimum song frequency of an urban colonist persists in a common garden experiment. bioRxiv, 761734.
Needham, K.B., Bergeon Burns, C., Graham, J.L., Bauer, C.M., Kittilson, J.D., Ketterson, E.D., Hahn, T., Greives, T.J., (2019). Changes in processes downstream of the hypothalamus are associated with seasonal follicle development in a songbird, the dark-eyed junco (Junco hyemalis). General and Comparative Endocrinology 270, 103–112. [35]
^Ketterson, Ellen D.; Nolan, Val (July 1976). "Geographic Variation and Its Climatic Correlates in the Sex Ratio of Eastern-Wintering Dark-Eyed Juncos (Junco Hyemalis Hyemalis)". Ecology. 57 (4): 679–693. doi:10.2307/1936182. ISSN0012-9658. JSTOR1936182.
^ abKetterson, Ellen D.; Nolan, Val; Cawthorn, Michelle J.; Parker, Patricia G.; Ziegenfus, Charles (2008-06-28). "Phenotypic engineering: using hormones to explore the mechanistic and functional bases of phenotypic variation in nature". Ibis. 138 (1): 70–86. doi:10.1111/j.1474-919x.1996.tb04314.x. ISSN0019-1019.
^Enstrom, David A.; Ketterson, Ellen D.; Nolan, Jr, VAL (1997-11-01). "Testosterone and mate choice in the dark-eyed junco". Animal Behaviour. 54 (5): 1135–1146. doi:10.1006/anbe.1997.0555. ISSN0003-3472. S2CID6826752.
^Casto, Joseph M.; Nolan, Jr., Val; Ketterson, Ellen D. (Apr 2001). "Steroid Hormones and Immune Function: Experimental Studies in Wild and Captive Dark-Eyed Juncos (Junco hyemalis)". The American Naturalist. 157 (4): 408–420. doi:10.1086/319318. ISSN0003-0147. PMID18707250. S2CID16296790.
