For bumblebees, big cities are a bummer. Layers of asphalt, concrete, brick and metal add up to fewer places for the insects to nest. But one big city—Detroit—reverses that trend. That means shrinking cities might be a growing opportunity for at-risk pollinators.
Bumblebees (species with the genus name Bombus) are, like other bees, in trouble. Their numbers and diversity are decreasing across North America. Other native wild bees—the insects that have been living here and pollinating our