Monarch butterflies lay their eggs exclusively on milkweeds. After hatching, caterpillars feed on milkweed leaves, which contain chemicals toxic to a common monarch parasite. But scientists have discovered that increased carbon-dioxide levels strip milkweeds of their medicinal properties.

The monarch population is in decline worldwide for many reasons. To protect monarchs, researchers are studying things like herbicides, habitat loss, parasites, global warming, and elevated levels of atmospheric carbon dioxide—among others—and how they affect both the butterflies and their milkweed hosts.

Meet Leslie Decker

Leslie Decker received her Ph.D. in Ecology and Evolutionary Biology at the University of Michigan. She is currently a Postdoctoral Scholar at Stanford University.

 

Milkweed in the Midwest

Monarch butterflies are notoriously picky eaters. They only feed off plants of the genus Asclepias, commonly known as milkweed, which are also the only plants monarchs lay their eggs on. Decker and her colleagues experimented with four types of milkweed.

 

Toxic Medicine

Milkweed is well known for making toxins called cardenolides. These toxins make monarchs taste bitter to predators, and also help protect against parasites.

 

Studying Plant-Insect Interactions

For her dissertation at the University of Michigan, Decker investigated what happens when elevated carbon dioxide levels alter the chemical qualities of milkweed. She also studied the effects of these changes on how monarchs defend themselves from natural enemies.

 

Seeing Changes in Plant Compounds

Decker's research shows changes in the medicinal compounds of milkweed. As temperatures rise and the atmosphere changes, other plants are changing their compounds, too.

 

Decker's Current Research Project at Stanford

Decker is currently researching how microbes in flower nectar interact with plant pollinators.

 

 

 

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