As the snow of winter in Nova Scotia fades away, 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 undergraduate student in environmental science at Dal’s agricultural campus in Bible Hill, N.S., is leading the research for her honours project. She is particularly interested in two species, aerial yellowjackets, and bald-faced hornets, which construct their nests by gathering wood or plant fibers from their surroundings. The insects chew the material to create a pulp that forms the nest.
Anticipating that nests in urban areas may contain higher levels of copper and chromium, common wood preservatives, Ashton explains that wasps in urban settings might ingest these metals from sources like decks, while those in rural areas are more likely to use natural materials like trees for nest-building.
Anyone who comes across an abandoned nest is encouraged to reach out to Ashton to contribute to the study. With the wasps perishing due to cold temperatures at this time of year, the mated queens seek shelter in places such as under tree bark or in woodpiles, logs, or leaf litter. Nests can often be found in barns, sheds, or trees. Ashton aims to gather all specimens by May before the wasps begin constructing new nests.
Despite the wear and tear on nests over winter, Ashton emphasizes that their condition does not affect the research. She plans to dry the nests in a microwave, dissolve the material, and use a machine to analyze it for heavy metal content.
This research, which has not been conducted on these species in Canada as far as Ashton knows, aims to determine if aerial yellowjackets and bald-faced hornets can serve as indicators of heavy metal presence. Assistant professor Paul Manning, one of Ashton’s project supervisors, highlights the importance of understanding the pressures these insects face, especially amid declining insect populations worldwide due to various stressors like habitat loss and pesticides.
Although the study does not focus on the effects of contamination on the wasps, previous research suggests that copper exposure can impact their lifespan and reproductive capacities. Manning underlines the significance of evaluating the presence and levels of contaminants to better comprehend the challenges insects encounter in their environments.
