Here is a sample of the current projects in the lab and some of the major themes. Please email me if you would like to see one of these papers! I’d be happy to send them.

Pest evolution of the Colorado potato beetle

Although the Colorado Potato Beetle is a major pest of potato and found throughout the Northern Hemisphere, there is relatively little known about its geographic and evolutionary origins as a pest. We are investigating the beetle’s evolutionary history because it may provide insight as to why this pest is so incredibly successful.164

One possible hypothesis is that Spanish conquistadors and Mexican ranchers brought the beetle’s natal host plant, Solanum rostratum, northwards beetle originated from the central Mexican highlands. We have been examining geographic beetle populations to determine how the beetle was successful in escaping its natural enemies and adapting to temperate potato agroecosystems. In particular, the beetle has been particularly effective in evolving resistance to all the major insecticides.

Our Major Questions

  • How are beetle populations related genetically?
  • How do geographic beetle populations vary in their response to temperate climatic conditions?
  • How do geographic beetle populations vary in their response to potato, Solanum tuberosum, and their native host plant, Solanum rostratum?
  • Do geographic beetle populations differ in their ability to evolve resistance to insecticides?


Victor Izzo, Tara Madsen-Steigmeyer


Selected Publications

Izzo, V. M., D. J. Hawthorne, and Y. H. Chen. In Press. Geographic variation in winter hardiness of a common agricultural pest, Leptinotarsa decemlineata, the Colorado potato beetle

Izzo, V. and Y. H. Chen. In Press. Time of the Season: Effect of photoperiodism on host-mediated cues for diapause induction in Leptinotarsa decemlineata. Ecological Entomology.

Piiroinen, S.,  L. Lindström, A. Lyytinen, J. Mappes, Y. H. Chen, V. Izzo*, A. Grapputo. 2013. Pre-invasion history and demography shape the evolution of the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Colorado potato beetle. BMC Evolutionary Biology 13:13.

Alyokhin, A. A., Y. H. Chen, M. Udalov, G. Benkovskaya, and L. Lindstrom. 2012. Evolutionary considerations in potato pest management. In P. Giordanengo, C. Vincent, and A. A. Alyokhin, Insect pests of potato: biology and management. Academic Press. Waltham, MA, USA.

Crop domestication and species interactions


Al l of the major crops that contribute to the human diet are domesticated and moved far from their geographic   region of origin. Selection on crops to meet human preferences for taste, harvestability, yield, and appearance may dramatically change plant morphological and chemical traits. We are have found that these changes can alter interactions between natural enemies and herbivores, potentially disrupting natural biological control.

Selected Publications:

Chen, Y. H., G. A. Langellotto, A. T. Barrion, and N. L. Cuong. 2013. Arthropod diversity and community composition in wild and cultivated rice fields in the Mekong Delta, Vietnam. Annals of the EntomDSCN0247ological Society of America 106(1): 100-110.

Chen, Y. H. and C. Bernal. 2011. Arthropod diversity and community structure on wild and cultivated rice. Agricultural and Forest Entomology 13:181-189.

Chen, Y. H. and S. C. Welter. 2007.  Crop domestication creates a refuge from parasitism for a native moth. Journal of Applied Ecology. 44: 238-245.

Chen, Y. H. and A. Romena. 2006. Feeding patterns of Scirpophaga incertulas (Lepidoptera: Crambidae) on wild and cultivated rice during the booting stage. Environmental Entomology 35(4): 1094-1102.


Modeling the impacts of Bt transgene flow on lepidopteran food web structure and stability on wild rice in Vietnam


Transgenic rice with the Bacillus thuringiensis (Bt) endotoxin may threaten wild arthropod diversity and community structure if the Bt toxin enters wild rice (O. rufipogon) populations. The objectives of this project are to: 1) document the diversity and abundance of non-target Lepidoptera and their natural enemies in wild rice ecosystems, 2) assess variation in nontarget lepidopteran susceptibility to Bt crop/wild hybrids, 3) determine the structure of a model lepidopteran-based food web, and 4) characterize lepidopteran-based food webs to predict how the Bt gene may impact arthropod food webs. Funded by USAID PBS-BBI Program