Tara Stewart Merrill, Post doctoral Researcher, Johnson Lab
Research interests: host-parasite interactions, ecological immunology, community ecology, wildlife disease

I work to incorporate the complexity of host-parasite interactions into our general understanding of infectious disease. In particular, my research focuses on the within-host dynamics of parasites and hosts and explores the role of host variation in parasite transmission. My research has a strong empirical basis and is motivated by ongoing collaborations with mathematicians and theoreticians. I am currently a postdoctoral fellow with the Life Sciences Research Foundation and am sponsored by the Simons Foundation. As a member of the Johnson lab, I am integrating host variation into our understanding of biodiversity-disease relationships.

I received my PhD in 2019 from the University of Illinois at Urbana-Champaign with Carla Cáceres. My dissertation addressed how immune defenses of invertebrate hosts scale up to affect disease spread at the population level. Prior to my doctoral work, I spent four years in the Ecological Parasitology lab at UC Santa Barbara with Armand Kuris, Kevin Lafferty and Ryan Hechinger. When I’m out of the lab/field/office, I enjoy traveling, hiking, birdwatching, cooking and listening to political podcasts.


Rapti, Z., Stewart Merrill, T.E., Mueller-Brennan, B., Kavoura, J.H. & Cáceres, C.E. 2019. Indirect effects in a planktonic disease system. Theoretical Population Biology 130:132-142.

Stewart Merrill, T.E., S.R. Hall, L. Merrill & C.E. Cáceres. 2019. Variation in immune defense shapes disease outcomes in laboratory and wild DaphniaIntegrative & Comparative Biology 59:1203-1219.

Merrill, L., T.E. Stewart Merrill, A. Barger & T.J. Benson. 2019. Avian health across the landscape: nestling immunity covaries with changing landcover. Integrative & Comparative Biology doi: 10.1093/icb/icz037

Stewart Merrill, T.E. & C.E. Cáceres. Within-host complexity of a plankton-parasite interaction. Ecology 99:2864-2867.

Rosencranz, J.A., K.D. Lafferty, K.M. Thorne, K.J. Buffington, J. Takekawa, R.F. Hechinger, T.E. Stewart, R.F. Ambrose, G.M. MacDonald, M. Holmgren, J. Crooks & R. Patton. 2018. Sea-level rise, habitat loss, and potential extirpation of a salt marsh specialist bird in urbanized landscapes. Ecology and Evolution 8:8115-8125

Stewart, T.E., M.I. Torchin & C.E. Cáceres. 2018. Invisible parasites and their implications for coexisting water fleas. Journal of Parasitology 104:101-105

Merrill, L., M. Naylor, M. Dalimonte, S. McLaughlin, T. Stewart & J. Grindstaff. 2017. Early life immune activation increases song complexity and alters phenotypic associations between sexual ornaments. Functional Ecology 31:2263-2273

Buck, J.C., R.F. Hechinger, A.C. Wood, T.E. Stewart, A.M. Kuris & K.D. Lafferty. 2017. Host density increases parasite recruitment but decreases host risk in a snail-trematode system. Ecology 98:2029-2038

Stewart, T.E. and S.A. Schnitzer. 2017. Blurred lines between competition and parasitism. Biotropica 49:433-438

Stewart, T.E. and L. Merrill. 2015. Host sex and parasitism in Red-winged Blackbirds (Agelaius phoeniceus): examining potential causes of infection biases in a sexually dimorphic species. Canadian Journal of Zoology 93:21-29

Merrill, L., T.E. Stewart, P.L. Gonzalez-Gomez, A.L. O’Loghlen, J.C. Wingfield, V.A. Ellis and S.I. Rothstein. 2014. Epaulet size and current condition in Red-winged Blackbirds: examining a semi-static signal, testosterone, immune function, and parasites. Physiological and Biochemical Zoology 88:11-21