As the snow of winter in Nova Scotia starts to melt away, researchers at Dalhousie University are urging the public to be on the lookout for abandoned paper wasp nests. They are gathering these nests from various locations in the province to examine them for potential contamination by heavy metals.
Carlie Ashton, an undergraduate student in environmental science at Dal’s agricultural campus in Bible Hill, N.S., is leading this research as part of her honours project. She is focusing on two specific species of wasps, aerial yellowjackets, and bald-faced hornets, which construct their nests by gathering wood or plant fibers from their surroundings. These insects chew the materials to create a pulp, which they then use to build their nests.
It is anticipated that nests in urban areas will likely have higher levels of copper and chromium, commonly found in wood preservatives, compared to nests in rural settings. Ashton explains that wasps in urban environments may be exposed to these heavy metals when chewing on materials like decks, whereas those in rural areas typically use natural sources like trees.
Anyone who comes across a nest is encouraged to contact Ashton to contribute to the study. During this time of year, nests are deserted as the wasps perish due to cold temperatures, with the mated queens seeking shelter elsewhere, such as under tree bark or in woodpiles. Ashton aims to collect all specimens by May, just as the wasps begin reconstructing new nests.
Although the nests may be weathered from winter conditions, this does not affect the research. Ashton plans to dry the nests in a microwave, dissolve the material, and analyze it for heavy metal content using specialized equipment.
This type of investigation has been carried out on other species elsewhere but has not been explored with these specific wasp species in Canada, according to Ashton. By determining if aerial yellowjackets and bald-faced hornets can indicate heavy metal concentrations, the project will shed light on the pressures these insects face.
Assistant professor Paul Manning, one of Ashton’s project supervisors, emphasizes that understanding the presence and levels of contaminants can provide insights into the challenges insects are encountering. While 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 abilities.
Manning notes the current global decline in insect populations due to various stressors like habitat loss and pesticides. The study aims to contribute to the broader understanding of these challenges faced by insects in the modern world.
