Ecology Fair University of Minnesota Monarch Lab
Willow Creek Middle School 1999
Willow Creek Middle School
2425 11th Ave SE
Rochester, MN 55604
Can Monarch Larvae Tolerate Small Amounts of Bt Toxin?
Monarch larvae were divided into eleven groups and fed various concentrations of Bt (Bacillus Thuringiensis) insecticide. The toxin was diluted with filtered water beginning with a 100% kill concentration for leaf chewing worms. The concentrations in each group were decreased incrementally down to a 0.375% concentration. Common milkweed leaves were dipped into the various concentrations. I observed each larvae daily, recording their growth in centimeters, molting status, and survival. All concentrations of Bt solution except the 0.375% group (4 drops per gallon) produced a 100% kill rate in the larvae. My findings were discussed with researchers at Cornell University and Iowa State. This insecticide is commonly used by organic farmers, perhaps in concentrations higher than would be necessary to control harmful pests. I believe that the effects of genetically engineered crops on harmless insects in general could be potentially disastrous as we incorporate more of them into the environment before evaluating their effects thoroughly.
What is Happening Inside the Chrysalis?
For my science project I have decided to scan monarch butterfly chrysalides to find out what happens inside; the changes that occur each day. So far we can see many breathing tubes streaming throughout the body of the chrysalis. Also visible is something that looks like lungs but may develop into wings. I learned that butterflies do not have lungs, and that some of the changes into a butterfly happen during the larva and J stages.