Researchers at the University of Toronto have discovered two species of bee in Ontario for the first time and one of them could pose a big threat to native mason bees.
The non-native mason bees (Osmia cornifrons and Osmia taurus) originate from northern Asia and were introduced to North America more than 50 years ago as crop pollinators.
O. taurus is the most concerning, said Scott MacIvor, a professor in the department biological sciences.
He said a recent study in the United States found that where they invaded, there was an eight-fold increase in O. taurus and a 90 per cent decline in six different species of native mason bees. The study was done across multiple mid-Atlantic states over a 13-year period.
“It’s too early to say whether this bee will have the same impact on native mason bees here in Canada, but it’s definitely a strong possibility,” he said.
“Entomologists in southern Ontario have been doing bee surveys for decades and it’s only within the last couple of years that they started to appear,” he said
One reason could be the recent popularity of bee hotels that people are using to support struggling native bee populations in urban areas. Both bee species are cavity-nesting bees, so they might be thriving due to the recent availability of these hotels.
Another potential way they’ve ended up in Canada could be the online sale of bee cocoons to gardeners and bee hotel owners.
He said people can help local mason bees by planting lupine, beardtongue, raspberry or redbud.
“If you are interested in native bee conservation, the best thing to do is build gardens with native flowering plants and pay attention and protect spots where nests develop naturally,” he said.
