WASHINGTON—The population of butterflies—the beautiful insects that play a vital role in pollination and the health of ecosystems—has fallen in the United States by more than a fifth this century, according to research spanning hundreds of species from the red admiral butterfly to the American lady to the cabbage white.
Data from about 76,000 butterfly surveys conducted by various groups documenting millions of the insects representing 554 species showed that their numbers dropped by 22 percent from 2000–2020 in the contiguous United States, researchers said. The scientists attributed the decrease to factors including habitat loss and pesticide use.
