What makes a non-native species “invasive”? And can a typically beneficial insect like a bee be deemed a threat to native species? The non-native bee Osmia cornifrons (shown here) was brought to the U.S. in 1978 to increase pollination in fruit orchards. But, unlike Osmia taurus, populations of Osmia cornifrons remained stable and did not rapidly increase. (Photo by David Biddinger, Ph.D.)