ReGrow Milkweed for Monarchs: Last call to participate!

Nathan Haan<haannath@msu.edu>, Michigan State University, Department of Entomology - July 14, 2020

You have until July 20 to join this crowd sourced MSU monarch butterfly conservation study.

New milkweed stems emerge after being cut back in early summer. Photo by Nathan Haan, MSU Entomology.

Monarch butterflies have arrived in the Midwest for the summer and their numbers are growing as the season progresses. This year, we launched the Michigan State University citizen science study ReGrow Milkweed for Monarchs, in which hundreds of people throughout the monarch’s range are helping test conservation techniques to improve its habitat. Participants cut back stems of the monarch’s host plant, milkweed, using a variety of different tools, which causes them to produce new shoots. It may be counterintuitive to cut back the very plant monarchs rely on, but our past research has found that in some circumstances, monarchs lay more eggs on milkweed regrowth than on older stems, and these eggs may be less likely to be eaten by other insects.

The first round of this study began in June. Participants cut back half of the stems in milkweed patches in more than 20 states and provinces and have been visiting them weekly to count monarch eggs and larvae. Now we’re looking to start a second round of the study, with new participants cutting back stems any time before July 20 and submitting data through August. Current participants are also welcome to join this second round of the experiment if they have other milkweed plants that weren’t included in the first round of the study.

In our past research, cutting back milkweed in July has produced interesting results. We’ve found that fewer milkweed stems tend to regrow if cut at this time (especially with dry weather), but the stems that do emerge are very attractive to monarchs and sometimes have quite a few eggs and caterpillars on them. Eggs that are laid in late summer produce the group of adult butterflies that make the trip back to Mexico, so we’re especially interested to learn if regrowing milkweed stems can give a boost to this group.

Visit our website, ReGrow Milkweed for Monarchs, where you can sign up to participate and learn more about our monarch research.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).