David Zaya
Join David Zaya, plant ecologist, as he explores ways to improve pollinator habitat through I-Pollinate

URBANA, Ill. - By studying plant communities, researchers can better understand what impacts monarchs as they lay their eggs. David Zaya, plant ecologist at the Illinois Natural History Survey, has studied how and why plant communities have changed. Citizens around the country can join his efforts to better understand the health of pollinators as part of the I-Pollinate program. 

University of Illinois Extension connects local citizen scientists with researchers of the I-Pollinate program. One of three researchers in the program, Zaya plants swamp milkweed (Asclepias incarnata) and counts the abundance of monarch eggs and larval throughout the growing season. 

"As we highlight the work of these scientists," says Extension Educator Kelly Allsup, "we hope that Illinois residents will join the research in their own communities and backyards." I-Pollinate is a citizen-science research initiative designed to collect statewide pollinator data. Volunteers may join as many as three research projects: monarch egg and caterpillar abundance, pollinator visitation to ornamental flowers, and bumble bee and honeybee distributions.

Zaya's research started in graduate school. "From their migration to and from Michoacan, Mexico, to the fact that we can watch them develop in our backyard, monarchs are cool and amazing in so many ways," he says. "Their showy display alerts predators that eating a monarch may make them sick."

Monarchs are in danger of disappearing, Zaya says, and may soon be listed as threatened or endangered by the U.S. Fish and Wildlife Service.  Monarch butterflies experience a wide variety of habitats, and many questions remain about how they respond to the different areas. Zaya's research examines how monarch egg laying and caterpillar growth responds to different garden and landscape variables.

“A major way to establish monarch conservation goals is to talk in terms of how many milkweed stems are present or have been added," Zaya says. "However, not all milkweed stems will be equally useful to monarchs." 

The I-Pollinate project may help researchers understand what conditions are most conducive to monarch reproduction. For example, monarch larvae seem to prefer eating swamp milkweed over other milkweed species.

“It is important to plant new swamp milkweeds for the study as the age and size of a milkweed affects its attractiveness to monarchs," Zaya says. "By limiting the study to newly planted milkweeds, we are leveling the conditions. It becomes easier to compare gardens rather than comparing the different milkweed plants."

Another aspects of this study will be identifying a caterpillar's age. Monarch larvae go through five stages, from coming out of the egg to forming a chrysalis. Each of those stages, called instars, can be differentiated by a combination of coloring, size, and length of tentacles on larvae front and back.

Successful monarch reproduction depends not only on the number of eggs laid, but on the likelihood those eggs hatch into larvae that survive long enough to reach adulthood. “By collecting data on the instar stage, we can estimate the monarch age and see if larvae survive better in certain areas of the state," Zaya says.

“Oleander aphids are a major pest on milkweeds," Zaya says. "A single plant can have tens of thousands of them in July and early August. Although they don't directly kill monarchs, but they can hurt the milkweed plants enough to affect monarch growth or attract creatures that might harm the plant or monarch larvae.”

Preliminary research suggests the size of a patch of milkweeds affects egg laying. Isolated milkweeds are harder for monarchs to locate.

From the data I-Pollinate citizens scientists submit, Zaya will study patterns across the state to compare different garden types and monarch populations. Learn more at I-Pollinate and contribute to Zaya's research on garden variability on monarch populations.

SOURCE: David Zaya, Plant Ecologist, Illinois Natural History Survey
SOURCE: Kelly Allsup, University of Illinois Extension, Horticulture Educator
EDITOR: Judy Mae Bingman, University of Illinois Extension, Marketing Communications Manager