Research interests: parasitology, host-parasite interactions, wildlife disease, diversity and inclusion

N122 CB334 Ramaley 

Boulder CO 80309

Monday-Thursday 7:00-3:00pm

On a large scale I am interested in wildlife and human host responses to parasites and specifically the underlying physiological consequences of infection. I have a diverse educational background including a veterinary technical degree from Colorado Mountain College and a Masters degree in systematic parasitology from Texas A&M University. Here in the Johnson Laboratory I work a dual role as our Laboratory Manager and as a Professional Research Associate (PRA). My manager duties include ordering supplies, hiring summer research technicians, permit applications and reports, assisting in grant submissions, and mentoring undergraduate and high school students. As a PRA, my expertise lies in identification of parasites using molecular and morphological techniques, developing and running ELISA, preparation and execution of laboratory and mesocosm experiments, animal husbandry, fecal analysis, and complete blood counts. Im also lucky to spend 20% of my time on diversity, equity and inclusion under the direction of Dr. Stefanie Johnson where we investigate drivers of diversity in science, like the NASA fellowship program. In my free time (hahaha) I enjoy hiking with my husband Forrest Lacey (Project Scientist at NCAR), daughter Macallynn and our two dogs (Inca and Trace), enjoying beverages at wonderful local breweries and wineries, and expanding my knowledge on diversity and inclusion.



Calhoun, D.M. (2022). Teacher Instructional Manual. Industrial Organizational Psychology. Taylor and Francis.

Stewart-Merrill, T.E., Calhoun, D.M., P.T.J. Johnson (2022). Beyond single host, single parasite interactions: Quantifying competence for competence for complete multi-host, mult-parasite communities. Functional Ecology (in press).


Falendysz, E.A., Calhoun, D.M., Smith, C.A., and Sleeman, J.M. (2021). Outside the box: Working with wildife in biocontainment. ILAR Journal ilab025.


Rose. D.P.*, Calhoun. D.M., and P.T.J. Johnson (2020). Infection prevalence and pathology of the cymothoid parasite Olencira praegustator in Atlantic menhaden. Invertebrate Biology 2020, 00:e12300.

Johnson, P.T.J., Calhoun, D.M., Riepe, T.B., McDevitt-Galles, T., and Koprivnikar, J. (2020). Community disassembly disease: realistic-but not randomized-biodiversity losses inhibit parasite transmission. Proceedings of the Royal Society of London B 286, 20190260.

Moss, W.E., McDevitt‐Galles, T., Calhoun, D.M., and Johnson, P.T.J. (2020). Tracking the assembly of nested parasite communities: using β‐diversity to understand variation in parasite richness and composition over time and scale. Journal of Animal Ecology 89, 1532-1542.

McDevitt-Galles, T., Moss, W.E., Calhoun, D.M., and Johnson, P.T.J. (2020). Phenological synchrony shapes pathology in host–parasite systems. Proceedings of the Royal Society B 287, 20192597.


Kohl, Z.F., Calhoun, D.M., Elmer, F., Peachey, R.B.J., Leslie, K.L., Tkach, V., Kinsella, J.M., and Johnson, P.T.J. (2019). Black-spot syndrome in Caribbean fishes linked to trematode parasite infection (Scaphanocephalus expansus). Coral Reefs.

Johnson, P.T.J., Calhoun, D.M., Riepe, T. B., and Koprivnikar, J. (2019). Community disassembly and disease: realistic-- but not randomized-- biodiversity losses enchance parasite transmission. Proceedings of the Royal Society B: 286.

Riepe, T.B., Calhoun, D.M., and Johnson, P.T.J.  (2019). Comparision of direct and indirect technique for evaluating endoparasite infections in wild-caught newts (Taricha torosa and Taricha granulosa). Diseases of Aquatic Organisms 134 137-146.

Stutz, W.E., Calhoun, D.M., and Johnson, P.T.J. (2019). Resistance and tolerance: a hierarchical framework to compare individual versus family-level host contributions in an experimental amphibian-trematode system. Experimental Parasitology 199, 80-91.

Calhoun, D.M., Leslie, K.L., Riepe, T.B., Achatz, T.J., McDevitt-Galles, T., Tkach, V.V., and Johnson, P.T.J. (2019). Patterns of Clinostomum marginatum infection in fishes and amphibians: integration of field, genetic, and experimental approaches. Journal of Helminthology 1-12.

Johnson, P.T.J., Calhoun, D.M., Riepe, T.B., and Koprivnikar, J. (2019). Chance or choice? Understanding parasite selection and infectin in multi-host communites. International Journal of Parasitology 49, 407-415.


Johnson, S.K., Fitza, M.A., Lerner, D.A., Calhoun, D.M., Chan, E.T. and Johnson, P.T.J.  (2018). Risky business: linking Toxoplasma gondii infection and entrepreneurship behaviors across individuals and countries. Proceedings of the Royal Society of London B 285, 20180822.

McDevitt-Galles, T., Calhoun, D.M., and Johnson, P.T.J. (2018). Parasite richness and abundance within aquatic macroinvertebrates: testing the role of host-and habitat-level factors. Ecosphere 9, e02188.

Calhoun, D.M., McDevitt-Galles, T., and Johnson, P.T.J. (2018). Parasites of invasive freshwater fishes and the factors affecting their richness and abundance. Freshwater Science 37, 134-146.

           PRESS: https://freshwater-science.org/news/in-drift-issue-31-spring-2018

Tornabene, B.J., Blaustein, A.R., Briggs, C.J., Calhoun, D.M., Johnson, P.T.J., McDevitt-Galles, T., Rohr, J.R., and Hoverman, J.T. (2018). Assessing the influence of landscape and environmental factors on ranavirusepidemiology in a California amphibian assemblage. Freshwater Biology 63, 639-651.

Johnson, P.T.J., Calhoun, D.M., Stokes, A.N., Susbilla, C.B., McDevitt-Galles, T., Briggs, C., Hoverman, J.T., Tkach, V., and de Roode, J. (2018). Of poisons and parasites-the defensive role of tetrodotoxin against infections in newts. Journal of Animal Ecology 87, 1192-1204.

Johnson, P.T.J., Stanton, D., Forshay, K., and Calhoun, D.M. (2018). Vertically challenged: how disease suppresses Daphnia vertical migration behavior.  Limnology and Oceanography 63, 886-896.


Hannon, E.R.*, Calhoun, D.M., Chadalawada, S.*, and Johnson, P.T.J. (2017). Circadian rhythms of trematode parasites: applying mixed models to test underlying patterns. Parasitology 1-9.

Calhoun, D.M., Bucciarelli, G.M., Kats, L.B., Zimmer, R.K., and Johnson, P.T.J. (2017). Noxious newts and their natural enemies: experimental effects of tetrodotoxin exposure on trematode parasites and aquatic macroinvertebrates. Toxicon 137, 120-127.

Koprivnikar, J., Riepe, T.B., Calhoun, D.M., and Johnson, P.T.J. (2017). Whether larval amphibians school does not affect the parasite aggregation rule: testing the effects of host spatial heterogeneity in field and experimental studies. Oikos 127, 99-110.


Calhoun, D.M., Woodhams, D., Howard, C.*, LaFonte, B.E.*, Gregory, J.R., and Johnson, P.T.J. (2016). Role of antimicrobial peptides in amphibian defense against trematode infection. EcoHealth 13, 383-391.

McAllister, C.T., Bursey, C.R., and Calhoun, D.M. (2016). Commensal protista, cnidaria and helminth parasites of the Cajun chorus frog, Pseudacris fouquettei (Anura: Hylidae), from Oklahoma. Proceedings of the Oklahoma Academy of Sciences 95.

Hannon, E.R.*, Kinsella, J.M., Calhoun, D.M., Joseph, M.B., and Johnson, P.T.J. (2016). Endohelminths in bird hosts from Northern California and an analysis of the role of life history traits on parasite richness. Journal of Parasitology 102, 199-207.


Calhoun, D.M., Schaffer, P.A., Gregory, J.R., Hardy, K.M.*, and Johnson, P.T.J. (2015). Experimental infections of bluegill with the trematode Ribeiroia ondatrae (Digenea: Cathaemasiidae): histopathology and hematological response. Journal of Aquatic Animal Health 27, 185-191.


Calhoun, D.M., Curran, S.S., Pulis, E.E., Provaznik, J.M., and Franks, J.S. (2013). Hirudinella ventricosa (Pallas, 1774) Baird, 1853 represents a species complex based on ribosomal DNA and affinity of the genus in Hemiurata Skrjabin & Guschanskaja, 1954 base on lsrDNA. Systematic Parasitology 86, 197-208.


Calhoun, D.M., and Dronen, N.O. (2012). A re-evaluation of specimens of Mesocoelium monas (Platyhelminthes: Digenea: Mesocoeliidae) form the National History Museum, UK and the United States National Parasite Collection, USA. Zootaxa 3589, 1-29.

Dronen, N.O., Calhoun, D.M., and Simcik, S.R. (2012). Mesocoelium Ohdner, 1901 (Digenea: Mesocoeliidae) revision of the family and re-evaluation of species composition in the genus. Zootaxa 3387, 1-96.


Calhoun, D.M. (2011). A re-evaluation of the taxonomy of Mesocoelium monas complex (Platyhelminthes: Digenea: Mesocoeliidae). Texas A&M University Masters thesis, 97 pp.


Calhoun, D.M. (2009). ABC’s of a CBC: An introduction to avian and mammalian complete blood count. Wildlife Rehabilitation 26, 133-142.

*undergraduate authors