Ames, Iowa — The decline of monarch butterfly populations is getting much attention, but lately, there’s doubt about the severity of the decline and whether it’s caused by the disappearance of milkweed, the only plant on which monarchs lay eggs.
Iowa State University researcher John Pleasants says monarch populations in the Midwest may appear stable because the counts are taken in open areas where the butterflies can find milkweed.
Herbicides have killed off many of the milkweed plants and Pleasants concludes monarchs are fewer in number because of it.
Pleasants estimates at least one-point-six-billion new milkweed stems need to be planted in the Midwest to restore the monarch population. He made his comments on the Iowa Public Radio program “Talk of Iowa.”
