From the field

Don't Believe the Buzz

The case of the disappearing bees is more complex than you think

Bianca Quijano
Scott MacGivor

Environmental conditions are threatening wild bees in Ontario, but too much focus is on the non-native honeybee, says Scott MacIvor. “There is misinformation about which bees need saving.”

By now you’ve read the headlines. You may have even watched a documentary or two. Bees all over the world are dying and it’s bad for everyone. But beware of false advice that might contribute to the problem.

“There is misinformation about which bees need saving,” says Scott MacIvor, a postdoctoral researcher in the Marc Cadotte Lab at UTSC and co-author of Bees of Toronto, part of the City of Toronto’s Biodiversity Booklet Series. “Especially in the promotion of ‘saving bees’ by keeping colonies of managed honeybees in natural areas and in cities, rather than supporting the needs of wild, native bees, which are mostly solitary and live all around us.”

In Ontario, wild bees face the same pressures as managed honeybees do, including landscape degradation and climate change. However, wild bees have additional pressure because of excessive numbers of managed honeybees. Honeybees are actually foreign to North America, brought here by Europeans in the 1600s.

“Honeybees can exhaust food supplies that are used by wild bees especially when managed in large densities, and in non-agricultural habitats like reserves, parks and cities.”

People with good intentions are getting into urban beekeeping without realizing this may contribute to negative impacts on wild bee populations.

And there’s one more thing that’s sucking the life out of Toronto’s wild bees.

Cynanchum rossicum, otherwise known as dog-strangling vine (DSV) is an invasive plant species affecting southern Ontario, Quebec and the northeastern United States.

“DSV out-competes the native plants that bees visit, and it is spreading rapidly through the city,” he explains. “Also, three-quarters of Toronto’s bee species nest in the ground. Since DSV covers the terrain, bees have fewer places to nest.”

The Cadotte Lab at UTSC has been monitoring the infestation of DSV in Rouge Park for years. This year, MacIvor and a team of undergraduates began investigating DSV’s impact on wild bees, sampling bee diversity in eight different sites with different invasion levels.

The team is also inspecting pollen samples, to find out which bees visit DSV and which do not. And they’re adding native plants to DSV-invaded habitats to see how invasion levels affect bee-visitation rates to native flowers.

With Professor Roberta Fulthorpe and her lab, they’re examining the microbial diversity found on bee pollen and flowers to better understand how invasion impacts bee-associated organisms.

“Bees are like the proverbial canary in the coal mine,” says MacIvor. “Understanding them will tell us a lot about the health of the environment.”

MacIvor hopes this work encourages the creation of pollinator-friendly habitats in Toronto’s public places.

Maybe it’s time to create more buzz about our native wild bees.