A researcher at Bowling Green State University (BGSU) is concerned about the implications of a new scientific study showing steep declines in some butterfly species across the U.S. over the last 20 years.
The study, published in the journal Science, revealed a 22% decrease in the total number of butterflies throughout U.S. regions between 2000 and 2020, and researchers say this is the most alarming data of its kind to date. People across the country, including here in Bowling Green, could see a decrease in the growth of fruits, vegetables and flowers if current trends in climate change and insecticide use cause pollinating butterflies to keep disappearing.
“Caterpillars and butterflies feed on plants, and climate change is causing some host plants to decrease in abundance,” said Daniel Pavuk, professor of biological sciences at BGSU. “There are also concerns about population declines due to insecticide applications, because some of the newer insecticides are extremely toxic to butterflies.”
Pavuk said there has also been a loss of natural butterfly habitats due to agricultural and urban-area expansion, naming a third condition making it harder for many butterfly species to sustain themselves.
“A lot of these declining species are what we call ‘univoltine,’ meaning they only complete one generation a year,” he said. “If there are really bad conditions for that one generation, it is harder for them to survive.”
Pavuk said population declines will have “rippling effects” on food webs because butterflies are critical to them as pollinators, predators and even food sources.
“Losing a major part of the food web will impact everything above and below it,” he said.
Pavuk said some short-term effects of a decrease in butterfly abundance might occur locally.
“Most people like songbirds, and we are already starting to see some serious declines in songbird populations due to a lack of caterpillars as a food source,” he said. “Some people also have flower and vegetable gardens at home, and they could see a decrease in growth due to issues with pollination.”
Pavuk said there could be a noticeable decrease in the production of fruits and vegetables over time, leading to changes in the foods available at local grocery stores.
“Butterflies are beneficial because they are usually pollinators of plants that are important to humans, both agriculturally and horticulturally,” he said. “If butterfly populations continue to decline, we will see a loss of variety in produce in supermarkets.”
Molly Evans, BGSU sophomore, said she would be personally affected by a decline in produce production.
“My mom buys fruits and vegetables every time she shops for food, and she always has a variety of them in the fridge,” she said. “When I’m at home especially, I eat them as snacks and as part of balanced meals.”
Pavuk said if the study’s historically high trends continue, more butterfly species could become endangered, but there are ways people can combat the issues causing declines in butterfly populations.
“People can plant butterfly-attracting plants in their yards,” Pavuk said. “More traditional weed control farmers used to use, like cultivation and cover crops, worked well.”
For some more information and resources on saving the butterflies, visit ncipmhort.cfans.umn.edu/butterflies.
