Occurrence of Danaus plexippus L. (Lepidoptera: Danaidae) on milkweeds (Asclepias syriaca) in transgenic Bt corn agroecosystems

Laura C.H. Jesse, John J. Obrycki

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The potential negative effects of transgenic Bt corn on the monarch butterfly, Danaus plexippus, requires quantification of the presence of D. plexippus in the field and of the effect of Bt corn tissues on oviposition and larval survival. During a 2-year field study, D. plexippus females laid similar number of eggs on Asclepias syriaca in corn fields and on A. syriaca growing in roadside habitats parallel to corn fields. In 1999 and 2000 similar number of D. plexippus larvae were observed on A. syriaca in corn fields and roadside habitats, whereas a greater proportion of A. syriaca in corn fields were infested by at least one D. plexippus larva in 2000. Similar number of eggs were laid in transgenic Bt and non-Bt corn fields, indicating that females did not avoid leaves dusted with anthers and 6-72 Bt pollen grains/cm2. Similar number of D. plexippus larvae were found in and near Bt corn fields compared to non-Bt corn fields following corn anthesis. In 2000, transgenic Event MON810 Bt corn pollen and anthers had no measurable effects on D. plexippus oviposition or larval survival.

Original languageEnglish
Pages (from-to)225-233
Number of pages9
JournalAgriculture, Ecosystems and Environment
Issue number1-3
StatePublished - Jul 2003

Bibliographical note

Funding Information:
We would like to thank Loren Handland, Steve Johnson, Kevin Peterson, and Ronald Stensland for allowing us to conduct this survey on their farms, and Kari Jovaag, Department of Statistics, Iowa State University, for assistance with statistical analysis. Funds for this research were provided by the Leopold Center for Sustainable Agriculture, Ames, IA, and the USDA Monarch/Bt Corn competitive grants program. Laura Jesse was supported by an Environmental Protection Agency STAR Fellowship. This is journal paper no. J-19282 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA. Project no. 3437, and supported by Hatch Act and State of Iowa funds.


  • Asclepias syriaca
  • Bt corn
  • Danaus plexippus
  • Risk assessment
  • Transgenic insecticidal crop

ASJC Scopus subject areas

  • Ecology
  • Animal Science and Zoology
  • Agronomy and Crop Science


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