Update on monarch butterflies in Iowa

May 23, 2017 1:07 PM
Blog Post

Monarch butterflies are an iconic species, known for their vibrant orange color and magnificent migration. Monarchs overwinter as adults in Central Mexico and fly to Texas and Oklahoma in the spring. Females lay eggs on milkweed plants, and the caterpillars feed on milkweed for about two weeks. After pupating as a chrysalis, the adult monarchs emerge and continue the northbound migration. Eventually, they reach Iowa around April-May and Canada by June. After four generations, the adults migrate back to Mexico every year to overwinter.

monarch egg on milkweed
Single monarch egg on the underside of a common milkweed leaf. The eggs are tiny with a slight yellow color, and the tip of the egg comes to a point.

Where are monarch butterflies NOW?

According to a citizen science platform, Journey North, the first monarch was spotted in Iowa on April 9. However, additional confirmations were few and far between through April and most of May. In the next few weeks, we can expect to see many more adults flying and caterpillars feeding on milkweed. From a report by Chip Taylor at MonarchWatch, monarchs numbers in Oklahoma were higher this year than previous years (see Chip’s blogs: Monarch Population Surprises and Spring roosting: A rare event). Monarchs were dumping eggs on small milkweed plants and roosting in trees, both behaviors are not typical of spring migrants. This should be an interesting year to keep up with monarch populations and movement.

The Iowa Monarch Conservation Consortium (Iowamonarchs.info) and the Monarch Research Team at Iowa State University are gearing up for a busy research season observing and studying monarchs and milkweed. Here are the latest updates from 2017:

The milkweed is ready! Ecology/Evolution and Organismal Biology graduate student, Tori Pocius, has been observing the interactions between monarchs and nine native species of milkweed. Already out in the field, Tori has found all nine species growing strong. Milkweed in Iowa is ready to be food for monarch caterpillars.

milkweed demonstration
Common milkweed demonstration at Reiman Gardens, Ames, IA.

We’ve seen adult monarch butterflies. Kelsey Fisher, a graduate student in Entomology, has been walking through restored prairies in search of adult butterflies. Some adults were seen in mid-April and even more have been observed in the past few weeks.

monarch butterfly on milkweed
Current ISU research includes monitoring adult flight behavior and interactions with milkweed.

We’ve seen eggs. Sydney Lizotte-Hall, a graduate student in Agronomy, and Teresa Blader, a graduate student in Entomology, have reported egg sightings on the underside of milkweed leaves. Teresa has observed eggs in her milkweed plots. Sydney reported finding 20 monarch eggs on milkweed in her backyard!

How can you help?

Since, milkweed is the only plant monarch adults use when laying eggs and the only food source that monarch caterpillars can eat, you can help monarchs by creating or preserving milkweed habitat. Use resources in Farm Bill programs to establish monarch breeding habitat; volunteer to establish monarch habitat on farms in consortium-sponsored demonstration projects; use monarch-friendly weed management in ditches, roadsides and other rights-of-way; and establish monarch gardens with native nectar plants and milkweeds in home and community spaces. Most simply, if you have milkweed on your property, let it grow. The Iowa Monarch Conservation Consortium recommends ways you can get involved and also created a handout for distribution.

Additionally, Journey North is a website that allows you to post sightings on monarch adults, eggs, and caterpillars. This website helps monarch enthusiasts all over the world understand monarch migration, abundance, and distribution. If you see a monarch, report your sighting!



Erin Hodgson Professor

Dr. Erin Hodgson started working in the Department of Entomology, now the Department of Plant Pathology, Entomology, and Microbiology, at Iowa State University in 2009. She is a professor with extension and research responsibilities in corn and soybeans. She has a general background in integrated...