Is the monarch butterfly at risk from the Bt corn pollen?
Many other studies have been published on non-target insects other than the monarch butterfly. Why do you think the Losey study received so much attention? Is the monarch butterfly more important than the other insects? Are there other reasons for this attention?
Given the results of the studies, what should the future implications be for these crops?
Do they need to have the same amount of regulation? Do they need to be regulated more strictly?
There are several ways this assignment can be assessed. The assignment can be graded strictly on a point basis for correctly answered questions and sufficiently supported argumentation. This would be the case in a take home assignment per individual student or small group.
The assignment can also be used as a class discussion where students form small groups to investigate the problem. Groups can then report their results to the class and the instructor can regulate the discussion. In this case learning can be assessed by participation at the group level.
The learning goals of this assignment can be seen if students are able to demonstrate a conclusion about the real risk of Bt to monarch, through a step-by-step assessment.
Answers to Student Handout Questions:
Click here to view answers
Articles for Review:
There are several articles that are included in this lesson. If you feel that the list is too extensive for your students to read you may exclude the Butterfly Survivor Article, Monarch Butterfly Natural Enemies, Bt Corn and European Corn Borer Information, and Monarch Overwintering Web links. These articles are meant to give the students a broader scope of the problem. It is suggested that the instructor read all the articles for a better understanding of the terms and articles surrounding this case study.
John E. Losey, Linda S. Rayor, Maureen E. Carter (Department of Entomology, Cornell University). Transgenic Pollen Harms Monarch Larvae . Nature, 399. May 20, 1999
Steven Milloy. “Butterfly Survivor”, Junkscience.com
Monarch Butterfly Natural Enemies
Bt Corn and European Corn Borer Information
Selected Monarch Research Papers
*To access the monarch papers, your institution must have a subscription*
(click here for more info)
Mark K. Sears, Richard L. Hellmich, Diane E. Stanley-Horn, Karen S. Oberhauser, John M. Pleasants, Heather R. Mattila, Blair D. Siegfried, and Galen P. Dively.
Impact of Bt corn pollen on monarch butterfly populations: A risk assessment
PNAS published September 14, 2001, 10.1073/pnas.211329998 ( Agricultural Sciences )
Effects of exposure to event 176 Bacillus thuringiensis corn pollen on monarch and black swallowtail caterpillars under field conditions
Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen
Corn pollen deposition on milkweeds in and near cornfields
Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies
Temporal and spatial overlap between monarch larvae and corn pollen
Student Assigment Sheet
Click here for student handout