In the summer of 2018, Andrea Gruver, a master’s student at the Chicago Botanic Garden and Northwestern University, was surveying bees in the Chicago metropolitan area. The section of Metra rail line that runs between the Garden and the downtown Clybourn station is an almost perfect gradient of urban development. So throughout the summer, Gruver and four young interns would climb aboard the train with their hand nets and pan traps to collect bees at eight different sites – areas immediately surrounding eight different train stations – along that stretch of the line.