Shawn Steffan


Research Entomologist, USDA-ARS Vegetable Crops Research Unit

Assistant Professor Dept. of Entomology, UW-Madison


My research centers on the American cranberry, Vaccinium macrocarpon, and within this system, I focus on the biology and ecology of arthropods. My program follows three main lines of inquiry: 1) investigations of the biology and phenology of pest species; 2) reduced-risk IPM approaches; and 3) trophic structure of the cranberry system. Wisconsin represents a particularly fruitful place in which to study the cranberry, largely because this plant is a native and presents both wild and cultivated populations around the State. And, Wisconsin leads the nation in cranberry production, making us “cranberry central.”




Dissertation: Biodiversity and fear ecology: the cascading effects of species richness and nontrophic interactions

Thesis: Flowering perennial hedgerows in annual agroecosystems: effects on cabbage pests and associated entomophaga in Wisconsin

Senior thesis: The Flower-visiting Insect Species of Coyote Brush in Berkeley, CA
Minor: American Literature

Publications (since 2010) 


Steffan, S.A., P.S. Dharampal, B.N. Danforth, H.R. Gaines-Day, Y. Takizawa, Y. Chikaraishi. (In review). Omnivory in bees: Elevated trophic positions among all major bee families. American Naturalist.

Steffan, S.A., and P.S. Dharampal. (Accepted). Undead food-webs: Integrating microbes into the food-chain. Food Webs.

Dharampal, P.S., C. Carlson, C.R. Currie, and S.A. Steffan. (In revision). Solitary bee larvae require pollen-borne microbes to survive. Proceedings of the Royal Society B.

Dharampal, P.S., C. Carlson, and S.A. Steffan. 2018. In vitro rearing of solitary bees: A tool for assessing larval risk factors. JoVE 137: e57876.

Steffan, S. A., M. E. Singleton, M. L. Draney, E. M. Chasen, K. E. Johnson and J. Zalapa. 2018. Arthropod Fauna Associated with Wild and Cultivated Cranberries in Wisconsin. The Great Lakes Entomologist, 50: 98-110.

van Zoeren, J., Guedot, C. and S.A. Steffan. 2018. Conserving carnivorous arthropods: an example from early-season cranberry (Ericaceae) flooding. The Canadian Entomologist, 00; 1-9.


Crossley, M. S., S. A. Steffan, D. J. Voegtlin, K. L. Hamilton, and D. Hogg. 2017. Variable isotopic compositions of host plant populations preclude assessment of aphid overwintering sites. Insects, 8(4): 128.

Steffan, S. A., P. S. Dharampal, L. Diaz-Garcia, C. R. Currie, J. E. Zalapa, and C. T. Hittinger. 2017. Empirical, metagenomic, and computational techniques illuminate the mechanisms by which fungicides compromise bee health. Journal of Visualized Experiments, 128.

Ohkouchi, N., Y. Chikaraishi, H. G. Close, B. Fry, T. Larsen, D. J. Madigan, M. D. McCarthy, K. W. McMahon, T. Nagata, Y. I. Naito, N. O. Ogawa, B. N. Popp, S. A. Steffan, Y. Takano, I. Tayasu, A. S. J. Wyatt, Y. T. Yamaguchi, and Y. Yokoyama. 2017. Advances in the application of amino acid nitrogen isotopic analysis in ecological and biogeochemical studies. Organic Geochemistry, 113: 150-174.

Steffan, S. A., E. M. Chasen, A. E. Deutsch, and A. Mafra-Neto. 2017. Multi-species mating disruption in cranberries (Ericales: Ericaceae): early evidence using a flowable emulsion. Journal of Insect Science, 54: 1-6.

Steffan, S. A., Y. Chikaraishi, P.S. Dharampal, J. N. Pauli, C. Guedot, and N. Ohkouchi. 2017. Unpacking brown food-webs: animal trophic identity reflects rampant microbivory. Ecology and Evolution, 7(10): 3532-3541.

Pauli, J. N., S. D. Newsome, J. A. Cook, C. Harrod, S. A. Steffan, et al. 2017. Opinion: why we need a centralized repository for isotopic data. Proceedings of the National Academy of Sciences, 114(12): 2997-3001. 

Takizawa, Y., P.S. Dharampal, S.A. Steffan, Y. Takano, N. Ohkouchi, and Y. Chikaraishi. Intra-trophic isotopic discrimination of 15N/14N for amino acids in plant flowers and leaves: Implications for isotopic ecological studies. 2017. Ecology & Evolution, 7(9): 2916-2924.

Schlautman, B., G. Covarrubias-Pazaran, D. Fajardo, S. A. Steffan and J. Zalapa. 2017. Discriminating power of microsatellites in cranberry organelles for taxonomic studies in Vaccinium and Ericaceae. Genetic Resources and Crop Evolution, 64(3): 451-466.

Steffan, S. A., M. E. Singleton, J. Sojka, E. M. Chasen, A. E. Deutsch, J. E. Zalapa, and C. Guedot. 2017. Flight synchrony among the major moth pests of cranberries in the Upper Midwest, USA. Insects, 8(1): 26. 

Blanke, C., Y. Chikaraishi, Y. Takizawa, S. A. SteffanP.S. Dharampal, and M. J. Vander Zanden. 2017. Comparing compound-specific and bulk stable nitrogen isotope trophic discrimination factors across multiple freshwater fish species and diets. Canadian Journal of Fisheries and Aquatic Sciences, 74(8): 1291-1297.


McMahon, E.E., S. A. Steffan, and C. Guédot. 2016. Population densities of lepidopteran pests in selected cranberry varieties in Wisconsin. Journal of Economic Entomology, 110(3): 1113-1119.

Covarrubias-Pazaran, G. L. Diaz-GarciaB. SchlautmanJ. DeutschW. SalazarM. Hernandez-OchoaE. GrygleskiS. A.  SteffanM. IorizzoJ. PolashockN. Vorsa and J. Zalapa. 2016. Exploiting genotyping by sequencing to characterize the genomic structure of the American cranberry through high-density linkage mapping. BMC Genomics, 17: 451.

Mills, N.J., V.P. Jones, C.C. Baker, T.D. Melton, S.A. Steffan, T.R. Unruh, D.R. Horton, P.W. Shearer, K.G. Amarasakare, and E. Miliczky. 2016. Using plant volatile traps to estimate the diversity of natural enemy communities in orchard ecosystems. Biological Control, 102: 66-76. 

Jones, V. P., J. M. Nicholas, J. F. Brunner, D. R. Horton, E. H.Beers, T. R. Unruh, P. W. Shearer, J. R. Goldberger, S. Castagnoli, N. Lehrer, E. Milickzy, S. A. Steffan, K. G. Amarasekare, U. Chambers, A. N. Gadino, R. K. Gallardo, and W. E.Jones. 2016. From planning to execution to the future: An overview of a concerted effort to enhance biological control in apple, pear, and walnut orchards in the western U.S. Biological Control, 102: 1-6.

Jones, V.P., D.R. Horton, N.J. Mills, T.R. Unruh, C.C. Baker, T.D. Melton, E. Miliczky, S.A. Steffan, P.W. Shearer and K. G. Amarasekare. 2016. Evaluating plant volatiles for monitoring natural enemies in apple, pear and walnut orchards. Biological Control, 102: 53-65.

Chasen, E.M., and S.A. Steffan. 2016. Temperature-mediated growth thresholds of the cranberry fruitworm, Acrobasis vaccinii (Lepidoptera: Pyralidae). Environmental Entomology 45: 732-736.


Steffan, S.A., Y. Chikaraishi, C.R. Currie, H. Horn, H.R. Gaines-Day, J.N. Pauli, J.E. Zalapa, and N. Ohkouchi. 2015. Microbes are trophic analogs of animals. PNAS 112, 15119-15124.      

Bernauer, O.M., H.R. Gaines-Day, and S.A. Steffan. 2015. Colonies of bumble bees (Bombus impatiens) produce fewer workers, less bee biomass, and have smaller mother queens following fungicide exposure. Insects 6, 478-488.

S.A. Steffan, Chikaraishi, Y., Horton, D.R., Miliczky, E., Zalapa, J.E., Jones, V.P. and N. Ohkouchi. 2015. Beneficial or not? Decoding carnivore roles in plant protection. Biological Control 91, 34-41

Chikaraishi, Y., S.A. Steffan, Y. Takano, and N. Ohkouchi. Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate. Ecology and Evolution 5, 2048-2059.

Deutsch, A.E., C.R. Rodriguez-Saona, J.E. Zalapa, and S.A. Steffan. 2015. Temperature-mediated development thresholds of Sparganothis sulfureana (Lepidoptera: Tortricidae) in cranberries. Environmental Entomology 44: 400-405.

Jones, V.P., D.R. Horton, N.J. Mills, T.R. Unruh, C.C. Baker, T.D. Melton, E. Miliczky, S.A. Steffan, and P.W. Shearer. 2015. Evaluating herbivore-induced plant volatiles and floral volatiles for monitoring natural enemies in apple, pear and walnut orchards. Biological Control.

Schlautman, B., D. Fajardo, T. Bougie, E. Wiesman, J. Polashock, N. Vorsa, S. Steffan, J. Zalapa. Development and validation of 697 novel polymorphic genomic and EST-SSR markers in the American cranberry (Vaccinium macrocarpon Ait.). Molecules 20, 2001-2013.

Pauli, J.N., S.A. Steffan, and S.D. Newsome. 2015. It is time for IsoBank. BioScience 65, 229-230.


Deutsch, A.E., C.R. Rodriguez-Saona, V. Kyryczenko-Roth, J. Sojka, J.E. Zalapa, and S.A. Steffan. Degree-day benchmarks for Sparganothis sulfureana (Lepidoptera: Tortricidae) development in cranberries. Journal of Economic Entomology 107:2130-2136.

Zalapa, J.E., T.C. Bougie, T.A. Bougie, B.J. Schlautman, E. Wiesman, A. Guzman, D.A. Fajardo, S.A. Steffan, and T. Smith. Clonal diversity and genetic differentiation revealed by SSR markers in wild Vaccinium macrocarpon and Vaccinium oxycoccos. Annals of Applied Biology 66: 196-207.

Pauli, J., J. Mendoza, S.A. Steffan, C. Cayelan, P.J. Weimer, and Z. Peery. 2014. A syndrome of mutualism reinforces the life history of a sloth. Proceedings of the Royal Society B 281: 20133006. 

Fajardo, D., B. Schlautman, S.A. Steffan, J.J. Polashock, N. Vorsa, and J.E. Zalapa. 2014. The American cranberry mitochondrial genome reveals the presence of selenocysteine (tRNA-Sec and SECIS) insertion machinery in land plants. Gene 536(2): 336-343. 

Chikaraishi, Y., S.A. Steffan, N.O. Ogawa, N.F. Ishikawa, Y. Sasaki, and N. Ohkouchi. 2014. High-resolution food webs based on nitrogen isotopic composition of amino acids. Ecology & Evolution doi: 10.1002/ece3.1103. 


Steffan, S.A., Y. Chikaraishi , D.R. Horton, N. Ohkouchi, M.E. Singleton,  E. Miliczky, D.B. Hogg, V.P. Jones. 2013. Trophic hierarchies illuminated via amino acid isotopic analysis.  PLoS ONE 8(9): e76152.

Fajardo D., J. Morales, H. Zhu , S. Steffan, R. Harbut, N. Bassil, K. Hummer, J. Polashock, N. Vorsa, and J. Zalapa. 2012. Discrimination of American cranberry cultivars and assessment of clonal heterogeneity using microsatellite markers. Plant Molecular Biology Reporter 31:264-271.

Steffan, S.A., J.C. Lee, M.E. Singleton, A. Vilaire, D.B. Walsh, L.S. Lavine, and K. Patten. 2013. Susceptibility of cranberries to Drosophila suzukii (Diptera: Drosophilidae). Journal of Economic Entomology 106:2424-2427.


Gable, J.T., D.W. Crowder, T.D. Northfield, S.A. Steffan, and W.E. Snyder. 2012. Niche engineering reveals complementary resource use. Ecology 93(9): 1994-2000.

Zalapa J.E., H. Cuevas, S. Steffan, H. Zhu, D. Senalik, E. Zeldin, B. McCown, R. Harbut, and P. Simon. 2012. Using next generation sequencing approaches to isolate simple sequence repeat (SSR) in the plant sciences. Methods and Applications of Next-Generation Sequencing in Botany. American Journal of Botany 99:193-208.


Jones, V.P. S.A. Steffan, N.G. Wiman, D.R. Horton, E. Miliczky, Q.H. Zhang, C.C. Baker. Evaluation of herbivore-induced plant volatiles for monitoring green lacewings in Washington apple orchards. Biological Control 56:98-105.


Steffan, S.A., and W.E. Snyder. 2010. Cascading diversity effects transmitted exclusively by behavioral interactions. Ecology 91: 2242-52.

Jones, V.P., S.A. Steffan, L.A. Hull, J.F. Brunner, and D.J. Biddinger. 2010. Effects of the loss of organophosphate pesticides in the US: Opportunities and needs to improve IPM programs. Outlooks on Pest Management 21:161-166.