Interview: Tracking Causes of The Decline of the Monarch Butterfly

University of Kansas insect ecologist Orley R. Taylor, who has been observing monarch butterflies and their spectacular migrations across North America for decades, says he has never been more concerned about their future. A new census taken at the monarchs’ wintering grounds in Mexico found their population had declined 59 percent over the previous year and was at the lowest level ever measured. In an interview with Yale Environment 360, Taylor talks about the factors that have led to the drop in the monarch population. Among them, he says, is the increased planting of genetically modified corn in the U.S. Midwest, which has led to greater use of herbicides, which in turn kills the milkweed that is a prime food source for the butterflies. “What we’re seeing here in the United States,” Taylor says, “is a very precipitous decline of monarchs that’s coincident with the adoption of Roundup-ready corn and soybeans.”

Read the interview