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Presentation
Corn pollen deposition on milkweeds in and near cornfields
Proceedings of the National Academy of Sciences USA
  • John M. Pleasants, Iowa State University
  • Richard L. Hellmich, Iowa State University
  • Galen P. Dively, University of Maryland - College Park
  • Mark K. Sears, University of Guelph
  • Diane E. Stanley-Horn, University of Guelph
  • Heather R. Mattila, University of Guelph
  • John E. Foster, University of Nebraska-Lincoln
  • Peter Clark, University of Nebraska-Lincoln
  • Gretchen D. Jones, United States Department of Agriculture
Document Type
Article
Publication Date
10-1-2001
DOI
10.1073ypnas.211287498
Abstract
The density of corn pollen on leaves of milkweed plants inside and outside of cornfields was measured in several studies from different localities. The purpose was to obtain a representative picture of naturally occurring pollen densities to provide a perspective for laboratory and field studies of monarch larvae feeding on milkweed leaves with Bt corn pollen. Pollen density was highest (average 170.6 grains per cm2) inside the cornfield and was progressively lower from the field edge outward, falling to 14.2 grains per cm2 at 2 m. Inside the cornfield, and for each distance from the field edge, a frequency distribution is presented showing the proportion of leaf samples with different pollen densities. Inside cornfields, 95% of leaf samples had pollen densities below 600 grains per cm2 and the highest pollen density observed was 1400 grains per cm2, which occurred in a study with a rainless anthesis period. All other studies had rainfall events during the anthesis period. A single rain event can remove 54–86% of the pollen on leaves. Leaves on the upper portion of milkweed plants, where young monarch larvae tend to feed, had only 30–50% of the pollen density levels of middle leaves.
Comments

This article is from Proceedings of the National Academy of Sciences USA; 98 (2001); 11919-11924; doi: 10.1073ypnas.211287498

Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Copyright Owner
National Academy of Sciences
Language
en
File Format
application/pdf
Citation Information
John M. Pleasants, Richard L. Hellmich, Galen P. Dively, Mark K. Sears, et al.. "Corn pollen deposition on milkweeds in and near cornfields" Proceedings of the National Academy of Sciences USA Vol. 98 Iss. 21 (2001) p. 11919 - 11924
Available at: http://works.bepress.com/richard_hellmich/3/