Kitchener-Waterloo

Milkweed location affects monarch butterfly success, says study

A study at the University of Guelph shows that — like human real estate principles —location and size matters when it comes to milkweed plantings aimed at helping monarch butterfly recovery programs.
Monarch reproduction is dependent on milkweed, which is often killed by herbicide. (Nature Saskatchewan)

A study at the University of Guelph shows that — like human real estate principles — location and size matters when it comes to milkweed plantings aimed at helping monarch butterfly recovery programs.

The research suggests monarch butterflies benefit more from milkweed planted in certain places than others. In addition, the size of a milkweed patch — smaller is better — also makes a difference.

Milkweed is critical to the survival of the monarch population because it's believed to be the only plant the butterflies feed on as caterpillars.

The University of Guelph study finds that restoring the plant along roadways is less effective than on agricultural lands.

Monarch butterfly populations have been in steep decline in recent decades, in part due to efforts to eradicate milkweed.

As a result, conservationists have been pushing for a program of milkweed planting, and the study suggests how doing so can be most effective.

The best approach appears to be small patches on agricultural lands, although using backyards can also help.


Cambridge, Ont. scientists want you to help track monarch butterfly populations as the number of butterflies making the long migration to Mexico each year declines.