Boulder County Bees revisited: a resampling of Boulder Colorado Bees a century later

Historic species lists for a region can be of great interest to biologists surveying modern faunas. In 2001, we initiated a 5-year field study to examine the status of insect pollinators in Boulder County grasslands, Boulder, Colorado. Century-old records of the bee fauna were available from bee specialist Cockerell’s publication (University of Colorado Studies, Boulder, 1907) The Bees of Boulder County. We predicted that 116 species originally found by Cockerell would occur in grassland habitats. We recorded 110 species, including several species not present in the 1907 collection. We conclude that the bees of the grasslands of Boulder County have been largely conserved, and we hypothesize that the large amount of preserved habitat in the county has contributed to maintaining the insects.