EXPERT ADVISORY: May 16 2024 – R0063

Male carpenter bees have a reputation for being aggressive, especially when they dive-bomb those who venture too close to the nests they’re guarding.

Lyllian Corbin (BSc ’19), a Brock University Biological Sciences PhD student, is fascinated with watching male carpenter bees in action and hopes to draw attention to the crucial pollinators as World Bee Day approaches on Monday, May 20.

In the spring, they emerge from their nests before the females and establish territories near the nest entrances to protect or pursue those females. They guard their territories by hovering and chasing, or even fighting, other bees that pose a risk.

Corbin’s interest in studying the role of hormones in aggression is not just academic. Bees play a critical role in the pollination of food crops and other plants — and some populations are declining, both in Canada and worldwide.

She is creating a two-fold experiment to study the way male carpenter bees interact with one another and whether hormones influence their behaviour.

As part of the project, she will set up tests to evaluate a pair of male bees within a circular tube, either in the lab or in the shade outdoors. By completing the testing in tubes, Corbin is better able to observe the bees’ interactions with one another compared to tracking them while they fly in open spaces.

The tubes also replicate the carpenter bees’ natural environment, as they nest in tunnels they have burrowed into wood. This creates a neutral setting for males to interact undisturbed by their surroundings.

Corbin will then apply a substance called methoprene, which mimics a hormone known to influence bee behaviour, to the carpenter bees’ abdomens.

“We’re going to observe their behaviour after a day or so to see if the elevated hormone level increases the male carpenter bees’ aggression and territoriality towards other males in any way,” she says.

The ability of male carpenter bees to guard nests could have an impact on young bees’ survival and female reproduction.

Previous research has shown male carpenter bees are getting smaller on average. Lower hormone levels could result in less guarding of nests by the males, with a possible impact of more predators attacking bee nests, Corbin says.

Found in insecticides, methoprene and other juvenile hormone mimics affect the development of insects from larvae to the adult stage.

“Since bees are key pollinators for a variety of plants and crops, further research on the effects of juvenile hormone mimics on bees’ behaviour will enhance our understanding of whether these human-induced changes to the environment pose a risk to wild bee populations,” says Corbin.

Her study is among research being conducted at Brock University’s Bee Lab, a group of undergraduate and graduate student researchers working under the direction of Professor of Biological Sciences Miriam Richards.

“The lab is focused on increasing our understanding of native bee species that are often missed by people who are unfamiliar with them,” says lab Research Assistant James Mesich.

The lab studies the behaviour, evolution and ecology of bees, mostly in Niagara, with an emphasis on sweat bees and carpenter bees. Much of the research occurs in human-modified landscapes, such as former landfill sites.

The team’s accomplishments include:

• Discovering two rare species of bumble bees on the Brock University campus.
• Sharing bee expertise in a segment of the TVO series Leo’s Pollinators.
• Producing a Niagara Community Observatory policy brief on protecting bees in Niagara.
• Research on bee population trends in Niagara’s Glenridge Quarry Naturalization site.

“Native bee species are under threat due to habitat loss and pesticide use, but there is hope,” says Mesich. “Our research is increasingly showing that efforts to create habitat for bees do work and can help these important pollinators thrive for generations to come.”

Brock University Biological Sciences PhD student Lyllian Corbin and Brock Bee Lab Research Assistant James Mesich are available for media interviews on this topic.

For more information or for assistance arranging interviews:

* Maryanne St. Denis, Manager, Content and Communications, Brock University mstdenis@brocku.ca or 905-246-0256 

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