Per unit of volume, the natural insecticide produced by the genetically modified maize plants is less toxic to insects than are many commercial insecticides commonly used on maize plants.

Standard weed-control practices that have been used by farmers for decades have largely eliminated milkweed plants from certain areas where monarch-butterfly caterpillars were once common.

The experiments showed that the caterpillars were not harmed by contact with the pollen from the genetically modified plants unless they ingested it.

The maize-eating insects that the natural insecticide protects against do not feed on the pollen of the maize plant.

Airborne maize pollen tends to collect on the middle leaves of milkweed plants and monarch caterpillars feed only on the plant's tender upper leaves.