As the snow of winter starts to disappear in Nova Scotia, researchers at Dalhousie University are urging the public to be on the lookout for abandoned paper wasp nests. These nests are being gathered from various locations across the province for a study on potential heavy metal contamination.
Carlie Ashton, an environmental science undergraduate student at Dal’s agricultural campus in Bible Hill, N.S., is leading the research as part of her honours project. She is focusing on two species, aerial yellowjackets and bald-faced hornets, which construct their nests by gathering wood or plant fibers from their surroundings. The insects chew on the material to create a pulp used to build the nest.
It is anticipated that wasp nests in urban areas will show higher levels of copper and chromium contamination, common wood preservatives, compared to nests in rural settings. This is because urban wasps may be chewing on materials like decks that are more likely to contain wood preservatives, as opposed to rural wasps that feed on natural sources like trees.
Ashton is requesting anyone who discovers a nest to reach out to her to contribute to the study. With the wasps perishing due to cold temperatures around this time of year, the abandoned nests can be found hanging in locations such as barns, sheds, or trees. Ashton aims to collect all specimens by May before the wasps begin constructing new nests.
Despite the wear and tear on the nests after winter, Ashton will dry the nest in a microwave, dissolve the material, and analyze it for heavy metals using specialized equipment. This kind of research has been conducted on other species elsewhere but not specifically on these species in Canada, according to Ashton.
Assistant professor Paul Manning, one of Ashton’s project supervisors, emphasized the importance of understanding the presence and levels of contaminants to comprehend the challenges faced by these insects amid declining global insect populations due to various stressors like heat stress, habitat loss, and pesticides.
While the study does not focus on the effects of contamination on the wasps, previous research has suggested that copper exposure can impact the lifespan of the insects and affect their reproductive capabilities. Manning highlighted that the research could provide insights into the pressures faced by aerial yellowjackets and bald-faced hornets in the environment.