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I am a behavioral and chemical ecologist who uses laboratory bioassays and field experiments to ask fundamental and applied questions about trees, their herbivores, and the natural enemies of herbivorous insects in forest ecosystems. The central focus of my research program is to identify and describe the underlying factors that contribute to the evolution and maintenance of chemical diversity within insects and plants, and how this ultimately affects their behavior and fitness. The results from my research will provide a better understanding of the ecological interactions of insects and plants within a tri-trophic framework, informing management of insects that are beneficial or damaging to forest ecosystems.
University of Illinois at Urbana-Champaign
Ph.D. Entomology, 2019
Advisor: Lawrence M. Hanks, Professor of Entomology, Dept. of Entomology
Committee: Brian Allan, May Berenbaum, Andrew Suarez
Relevant Coursework: Applied Multivariate Methods, Behavioral Ecology, Fundamentals of Insect Pest Management, Genomic Analysis of Insects, Insect Classification and Evolution, Insect Ecology, Insect Physiology, Seminars: Chemical Ecology, Genomics, Mutualism, Phytochemicals in Pest Management, Speciation
Dissertation Project: "Response by natural enemies to signals and cues associated with beetles in the family Cerambycidae"
University of Wisconsin-Madison
M.S. Entomology, 2013
Advisor: Kenneth F. Raffa, Professor of Forest Entomology, Dept. of Entomology
Committee: David G. Hogg, Shawn Steffan, Daniel K. Young
Relevant Coursework: Univariate Statistics, Regression Analysis, Insects and Diseases in Forest Resource Management, Introduction to Entomology, Plant-Microbe Interactions, Seminar in Pollination Biology
Thesis Project:“The behavior of parasitoids of the invasive emerald ash borer, Agrilus planipennis, and Hymenoptera and Coleoptera associated with three native Agrilus species”
B.S. Biology, 2009
Relevant Coursework: Botany, Field Botany, Ecology, Ecology of Tropical Forests, Plant-Insect interactions, GIS, Organic Chemistry, Biochemistry, Molecular Genetics, Genomics
Independent Research Project: Studied propagation techniques of M. patula as well its role in remediation at the Lehigh Gap, a superfund site contaminated with heavy metals. Advisor: Diane Husic, Spring 2007
Louisiana State University
Department of Entomology
2022 – Present: Assistant Professor of Forest Entomology
University of New Hampshire
Dept. of Nat. Res. Environment, Garnas Lab
2019 – 2022: Postdoctoral Research Associate
Postdoctoral project: Research evaluating the role of ontogeny on defensive metabolite production in green and white ash, as well as studying the impacts of ontogeny on the fitness of the invasive emerald ash borer (Coleoptera: Buprestidae: Agrilus planipennis) and the introduced biological control agents, Spathius galinae and Tetrastichus planipennisi. This project has involved substantial field and lab work over three field seasons, felling and sampling of hundreds of ash trees, and the analysis of univariate and multivariate data with R and Python.
University of Illinois at Urbana-Champaign
Department of Entomology, Hanks Lab
Sp 2015, 2019; Fa 2016, 2018; Su 2014 – 2018: Research Assistant
Field and laboratory research on the chemical ecology of cerambycid beetles and their associates (i.e., potential competitors and natural enemies). This included the collection of volatile pheromones of cerambycids with aerations and SPME, identification and comparison of pheromones with authentic standards in GC/MS, and validation of identified compounds with subtractive trapping studies in the field. Additional work involved preliminary isolation of putative pheromones from elaterid and staphylinid beetles with SPME, as well as literature reviews and analysis of data collected of bycatch from traps.
University of Wisconsin-Madison
Department of Entomology, Raffa Lab
2011 – 2013 Research Assistant
Continued to coordinate and execute monitoring and analysis of Wisconsin's five year biological control release program, a multi-agency effort (UW-Madison, WI Dept. Natural Resources, WI Dept. Agriculture Trade & Consumer Protection, USDA-APHIS), of three introduced parasitoids, from the emerald ash borer's home range, in an attempt to control the destructive pest.
2010 – 2011 Research Intern
Studied the microbial associations of three buprestids, the invasive emerald ash borer and two native species of Agrilus, twolined chestnut borer (Agrilus bilineatus) and bronze birch borer (Agrilus anxius). I also began preliminary work examining the behavior of two parasitoids of A. planipennis, Spathius floridanus and Spathius agrili. Lastly, I was responsible for coordinating and executing Wisconsin's first biological control release against the emerald ash borer, a multi-agency effort (UW-Madison, WI Dept. Natural Resources, WI Dept. Agriculture Trade & Consumer Protection, USDA-APHIS), of three exotic parasitoids from the native range of EAB, to slow the growth of populations of this destructive pest.
Johnson, T.D., M.L. Buffington, M.W. Gates, R.R. Kula, and E. Talamas. 2021. Deployment of aggregation-sex pheromones of longhorned beetles (Coleoptera: Cerambycidae) facilitates the discovery and identification of their parasitoids. J. Chem. Ecol. 47: 28–42.
Hanks, L.M., J.A. Mongold-Diers, R.F. Mitchell, Y. Zou, J.C.H. Wong, L.R. Meier, T.D. Johnson, and J.G. Millar. 2019. The role of minor pheromone components in segregating 14 species of longhorned beetles (Coleoptera: Cerambycidae) of the subfamily Cerambycinae. J. Econ. Entomol. 112: 2236–2252.
Johnson, T.D., E. Hanson%, and A. Yu%. 2019. Adults of the cerambycid beetle Megacyllene caryae use both olfactory and visual information to locate mates. Entomol. Exp. et Appl. 167: 500–506.
Millar, J.G., R.F. Mitchell, L.R. Meier, T.D. Johnson, J.A. Mongold-Diers, L.M. Hanks. 2017. (2E,6Z,9Z)-2,6,9-Pentadecatrienal as a male-produced aggregation-sex pheromone of the cerambycid beetle Elaphidion mucronatum. J. Chem. Ecol. 43: 1056–1065.
Diesel N.M., Y. Zou, T.D. Johnson, D.A. Diesel, J.G. Millar, J.A. Mongold-Diers, and L.M. Hanks. 2017. The rare North American cerambycid beetle Dryobius sexnotatus shares a novel pyrrole pheromone component with species in Asia and South America. J. Chem. Ecol. 43: 739–744.
Johnson, T.D., J.A. Pfammatter, J.P. Lelito, and K.F. Raffa. 2016. Evaluation of tree mortality and parasitoid recoveries on the contiguous western invasion front of emerald ash borer.Agr. For. Entomol. 18: 327–339.
Leung, W., ...T.D. Johnson, ...S.C.R. Elgin 2015. Drosophila Muller F elements maintain a distinct set of genomic properties over 40 million years of evolution. G3. 5: 719–740.
Johnson, T.D., J.P. Lelito, and K.F. Raffa. 2014. Responses of two parasitoids, the exotic Spathius agrili Yang and the native Spathius floridanus Ashmead, to volatile cues associated with the emerald ash borer, Agrilus planipennis Fairmaire. Biol. Control 79: 110–117.
Johnson, T.D. 2020. What goes up must come down–the completion of field research on emerald ash borer at Doe Farm. Doe Farm Newsletter. 16 October 2020.
Johnson, T.D. 2020. Another update regarding emerald ash borer research at Doe Farm. Doe Farm Newsletter. 4 September 2020.
Johnson, T.D. 2020. A second update regarding emerald ash borer research at Doe Farm. Doe Farm Newsletter. 31 July 2020.
Johnson, T.D. 2020. Emerald ash borer research update at Doe Farm. Doe Farm Newsletter. 24 June 2020.
Anderson, N.+, Halsey, S+., Johnson, T.D.+, T. Josek+, and E. Welsh+. 2018. The world has a place for pesky blood suckers. The News Gazette. (Also read on WILL Radio)
Johnson, T.D., and C.A.E. Dean. 2017. Humans and arthropods, who should fear whom? The News Gazette (Also read on WILL Radio).
Johnson, T.D., Gibson, J., and T. Josek. 2016. Bugs go Boom. The News Gazette. (Also read on WILL Radio).
Duennes, M.A., and T.D. Johnson. 2014. Pesticides should be small tool in management plan. The News Gazette. (Also read on WILL Radio)
Animal Behavior Society
March 2018 – Present
Entomological Society of America
March 2012 – Present
International Organization for Biological Control
December 2015 – Present
International Society of Chemical Ecology
February 2014 – Present