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Faculty Profile
Cynthia Downs

Associate Professor

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345 Illick Hall


Lab website

Website for the Downs Lab


Ph.D. Ecology Evolution & Conservation Biology, University of Nevada, Reno, NV, 2011

B.S. Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, NY, 2004

Research Overview

Scaling and tradeoffs in animal physiology; mostly immune defenses; mostly an ecological or evolutionary context.

Research Summary

I am an ecological physiologist who investigates how the diverse physiological traits expressed by animals alter an animal’s interaction with its environment and mediates the animal’s ecology, population dynamics, and evolutionary trajectories.  My research is largely focused at the organismal level, but because organismal-level phenotypes are not independent of each other, of the mechanisms that mediate expression of phenotypes, or of ecological and evolutionary history, I integrate studies across biological levels.  Specifically, my program seeks to understand (1) mechanisms that mediate physiological traits and trade-offs, (2) how physiological traits determine life histories and population dynamics, and (3) how environmental conditions affect physiological phenotypes.  Much of my work asks questions in the area of ecological immunology.

Courses taught

EFB 462 - Animal Physiology: Environmental and Ecological. An introduction to the physiology of adaptation to the physical and biotic environments, including animal energetics, biology of body size and physiological constraints on animal life history. 

EFB 480 - Principles of Animal Behavior. Basic principles of animal behavior and the scientific process. Proximate and ultimate mechanisms controlling the behavior of animals including humans, with an emphasis on evolution.


Updated Sept. 2020

* = undergraduate, intern author, **graduate student author

Refereed Journal Articles

Downs, CJ, LA Schoenle, SJ Oakey*, R Ball, RHY Jiang, LB Martin. In press. Large mammals have more powerful antibacterial defenses than expected from their metabolic rates. American Naturalist. (BioRxiv preprint:

Claunch, NM**, CJ Downs, LA Schoenle, SJ Oakey*, T Ely, C Romagosa, CW Briggs. 2022. Snap-freezing in the field: effect of sample processing time on performance of bactericidal assays. Integrative and Comparative Biology: icac007. doi:10.1093/icb/icac007

Martin, LB, EC Ruhs, S Oakey*, and CJ Downs. 2022. Leukocyte allometries in birds are not affected by captivity. Journal of Experimental Zoology, Part A 337: 576-582. doi: 10.1002/jez.2591.

Garland, TG Jr., CJ Downs, Ives, AR. 2022. Trade-offs (and constraints) in organismal biology: beyond energetics. Physiological and Biochemical Zoology 95: 82-112.

Ohmer, MEB, D Costantini, G. Czirják, CJ Downs, LV Ferguson, A Flies, CE Franklin, A Kayigwe, S Knutie, CL Richards-Zawacki, RL Cramp. 2021. Applied Ecoimmunology: Using immunological tools to improve conservation efforts in a changing world. Conservation Physiology 9: oab074. doi: 10.1093/conphys/coab074.

Ruhs, EC, DJ Becker, SJ Oakey*, O. Ololade*, B Fenton, N Simmons, LB Martin, CJ Downs. 2021. Body size shapes immune cell proportions in birds and non-volant mammals, but not bats. Journal of Experimental Biology 224: jeb.241109

Jimenez, AG, CJ Downs, S. Lalwani*, W. Cipolli. 2021. Cellular metabolism and IL-6 concentrations during stimulated inflammation in small and large dog breeds’ primary fibroblasts cells, as they age. Journal of Experimental Biology 224: jeb233734.

Sangunaraj, F**, JR St. Juliana**, CJ Downs, IS Khokhlova, L Koren, D Matas, KE Wynne-Edwards, BP Kotler. 2021. Positive association between cage-measures of GUD (giving-up density) and experimental cortisol increases in wild-caught gerbils. Israel Journal of Ecology and Evolution. doi:10.1163/22244662-bja10014

Levesque, DL, JG Boyles, CJ Downs, and AM Breit**. 2021. High body temperature is an unlikely cause of high viral tolerance in bats. Journal of Wildlife Diseases 57:238-241.

Ruhs, EC, LB Martin, CJ Downs. 2020. The impact of body mass on immune cell concentrations in birds. Proceedings of the Royal Society: B. 287:20200655. doi:10.6084/m9.figshare.c.5097088.

Bleicher, S**, B Kotler, CJ Downs, JS Brown. 2020. Intercontinental test of constraint-breaking adaptations: testing behavioural plasticity in the face of a predator with novel hunting strategies. Journal of Animal Ecology. doi:10.1111/1365‐2656.13234

Jimenez, AG and CJ Downs. 2020. Untangling lifespan and body mass discrepancies in canids: Phylogenetic comparison of oxidative stress in blood from domestic dogs and wild canids. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 319: R203-R210.

Downs, CJ, JL Brown, B Wone, ER Donovan, JP Hayes. 2020. Effects of selection for mass-independent maximal metabolic rate on food consumption. Physiological and Biochemical Zoology 93:23-36.

Downs, CJ, NA Dochtermann, R Ball, KC Klasing, LB Martin. 2020. The effects of body mass on immune cell concentrations of terrestrial mammals. American Naturalist 195:107-114.

Bleicher, S**, B Kotler, CJ Downs, JS Brown. 2020. Heteromyid rodents play to their evolutionary strengths and provide opposite snake evasion strategies in the face of known and novel snakes. Journal of Arid Environments 173:104025.

Becker, DJ, CJ Downs, LB Martin. 2019. Multi-scale drivers of immunological variation and consequences for disease dynamics. Integrative and Comparative Biology.

Jimenez, AG, E O’Connor*, K Tobin*, K Anderson*, JD Winward*, A Fleming*, C Winner*, E Chinchilli*, M Amy*, K Carlson*, and CJ Downs. 2019. Does cellular metabolism from primary fibroblasts and oxidative stress in blood differ between mammals and birds? The (lack-thereof) scaling of oxidative stress. Integrative and Comparative Biology.

Vennum, C**, CJ Downs, JP Hayes, I Huston*, MW Collopy, B Woodbridge, CW Briggs. 2019. Early life conditions an immune defense in nestling Swainson’s hawks. Physiological and Biochemical Zoology 92:419-429.

Downs, CJ, LA Schoenle, BA Han, JF Harrison, LB Martin. 2019. Scaling of host competence. Trends in Parasitology 35:182-192.

Warburton, EM, IS Khokhlovam, L van der Mescht, CJ Downs, EM Dlugosz, BR Krasnov. 2019. Effects of maternal and grandmaternal flea infestation on offspring quality and quantity in a desert rodent: evidence for transgenerational phenotypic plasticity. International Journal of Parasitology 49: 481-488.

Vitousek, MN, MA Johnson, CJ Downs, ET. Miller, LB Martin, CD Francis, J Donald, MJ Fuxjager, LZ Garamszegi, W Goymann, M Hau, JF Husak, B Kircher**, R Knapp, LA Schoenle, TD Williams. 2019. Macroevolutionary patterning in glucocorticoids suggests different selective pressures shape baseline and stress-induced levels 193. American Naturalist 193: 866-880. doi/10.1086/703112.

Francis CD, J Donald, MJ Fuxjager, LZ Garamszegi, W Goymann, M Hau, JF Husak, MA Johnson, B Kircher**, R Knapp, LB Martin, EI Miller, LA Schoenle, MN Vitousek, TD Williams, CJ Downs. 2018. Metabolic scaling of stress hormones in vertebrate animals. Integrative and Comparative Biology icy063: 1-10.

Johnson MA, CD Francis, EI Miller, CJ Downs, MN Vitouseki. 2018. Detecting bias in a large-scale comparative analysis: methods for expanding the scope of hypothesis-testing with HormoneBase. Integrative and Comparative Biology icy045: 1-9.

Downs, CJ, BV Boan**, TD Lohuis, KS, Stewart. 2018. Investigating relationships between reproduction, immune defenses, and cortisol in Dall sheep. Frontiers in Immunology 9:105. doi: 10.3389/fimmu.2018.00105

MacColl, E*, K Vanesky*, JA Buck, BM Dudek**, CA Eagles-Smith, JA Heath, G Herring, C Vennum**, CJ Downs. 2017. Correlates of immune defenses in golden eagles. Journal of Experimental Zoology, Part A 327: 243-253.

Ben-Hamo, Mᶧ,**, CJ Downsᶧ, DJ Burns, B Pinshow. 2017. House sparrows offset the physiological trade-off between immune response and feather growth by adjusting foraging behavior. Journal of Avian Biology 48: 837-845. doi: 10.1111/jav.01252
ᶧEqually contributing authors.

LaDage, L, TC Roth II, CJ Downs, B Sinervo, VV Pravosudov. 2017. Increased testosterone decreases medial cortical volume and neurogenesis in territorial side-blotched lizards (Uta stansburiana). Frontiers in Neuroscience 11: 97. doi: 10.3389/fnins.2017.00097

Downs, CJ, JL Brown, B Wone, ER Donovan, JP Hayes. 2016. Speeding up growth: selection for mass-independent maximal metabolic rate alters growth rates. American Naturalist 187: 295-307. DOI: 10.1086/684837

Downs, CJ, B Pinshow, IS Khokhlova, BR Krasnov. 2015. Flea fitness is reduced by high fractional concentration of CO2 that simulate levels found in their hosts' burrows. Journal of Experimental Biology 218: 3596-3603.

Downs, CJ, KM Stewart, BL Dick. 2015. Investment in constitutive immune function by North American elk experimentally maintained at two different population densities. PLoS One 10:e0125586

Wone, BWM, P Madsen, ER Donovan, MK Lobocha, MW Sears, CJ Downs, DA Sorensen, JP Hayes. 2015. A strong response to selection on mass-independent maximal metabolic rate without a correlated response in basal metabolic rate. Heredity 114: 419-427.

Downs, CJ, KM Stewart. 2014. A primer in ecoimmunology and immunology for wildlife research and management. California Fish and Game 100: 369-393.

Downs, CJ, JS Adelman, GE Demas. 2014. Mechanisms and methods in ecoimmunology: integrating within-organism and between-organism processes. Integrative and Comparative Biology 54: 340-352. doi: 10.1093/icb/icu082.

Downs, CJᶧ, NA Dochtermannᶧ. 2014. Testing hypotheses in ecoimmunology using mixed models: disentangling hierarchical correlations. Integrative and Comparative Biology 54: 407-418. doi: 10.1093/icb.icu035.
ᶧEqually contributing authors.

Dlugosz, EM, CJ Downs, IS Khokhlova, AA Degen, BR Krasnov. 2014. Host reproductive status and reproductive performance of a parasite: offspring quality and trade-offs in a flea parasitic on a rodent Parasitology 141: 914-924.

Dlugosz, EM, CJ Downs, IS Khokhlova, AA Degen, BR Krasnov. 2014. Ectoparasite performance on reproducing mammalian females: an unexpected decrease on pregnant hosts. Journal of Experimental Biology 217:1058-1064.

Downs, CJ, JL Brown, B Wone, ER Donovan, K Hunter, JP Hayes. 2013. Selection for increased mass-independent maximal metabolic rate suppresses innate but not adaptive immune function. Proceedings of the Royal Society: B 280: 20122636.

Dlugosz, EM**, H Schutz**, TH Meek**, W Acosta**, CJ Downs, EG Platzer, MA Chappell, T Garland. 2013. Immune response to a Trichinella spiralis infection in house mice from lines selectively bred for high voluntary wheel running. Journal of Experimental Biology 216: 4214-4221.

Downs, CJ, H Schutz, TH Meek**, EM Dlugosz**, W Acosta**, KS de Wolski*, JL Malisch, JP Hayes, T Garland. 2012. Within life-time trade-offs but evolutionary freedom for hormonal and immunological traits: evidence from mice bred for high voluntary exercise. Journal of Experimental Biology 215: 1651-1661.

Downs, CJ, SB Vander Wall. 2009. High relative humidity increases pilfering success of yellow pine chipmunks. Journal of Mammalogy 90: 796-802.

Vander Wall, SB, CJ Downs, M Enders, BA Waitman. 2008. Do yellow-pine chipmunks recover their own caches? Western North American Naturalist 68: 319-325.

Downs, CJ, JP Hayes, CR Tracy. 2008. Scaling metabolic rate with body mass and inverse body temperature: A test of the Arrhenius fractal supply model. Functional Ecology 22: 239-244.

Book Chapters:

Schoenle, LA, CJ Downs, LB Martin. 2018. An Introduction to Ecoimmunology. In: EL Cooper, editor. Advances in Comparative Immunology, Springer: 901-032.

Refereed Case Studies:

Ruhs, E and CJ Downs. 2021.  Case Study: A delicate balance: resource allocation, immunity and disease in birds. National Center for Case Study Teaching in Science.

Schoenle, LA and CJ Downs. 2018. Coping with infection: resistance and tolerance of parasites in Soay sheep. National Center for Case Study Teaching in Science.

Current Graduate Advisees

Ben AkerBen Aker

  • Degree Sought: PHD
  • Graduate Advisor(s): Downs
  • Area of Study: Environmental & Forest Biology

Theo BlackTheo Black

  • Degree Sought: PHD
  • Graduate Advisor(s): Leydet and Downs
  • Area of Study: Environmental Biology

Eaqan ChaudhryEaqan Chaudhry

  • Degree Sought: PHD
  • Graduate Advisor(s): Downs
  • Area of Study: EFB Ecology