But if you talk to the scientists they will tell you that their conclusions will not change. It's really hard to find a cornfield that doesn't have milkweed in the cornfield, or milkweed surrounding the cornfield. In fact, milkweed is primarily weed in old fields, abandoned fields, and roadsides. That's true all over the breeding area. After months of torpor, they awaken, mate, and head north.
Females stop to lay eggs along the Gulf Coast, then die.
The new monarchs pick up the trail, eventually scattering throughout North America. They continue to breed during the summer. Several generations later, in early fall, a new flock of butterflies migrates south. If large numbers of these larvae were to be killed off by exposure to pollen, or growth was delayed, it could have a profound effect on the migration. Analyzed with computer models, the overlap between pollen shed and monarch larvae ranged from zero to one hundred percent.