This summer, many prairie cities experienced a surge in mosquito populations, leading to a shortage of bug spray in stores in Manitoba, Saskatchewan, and Alberta due to high demand. Data from the City of Edmonton revealed a significant increase in mosquitoes, 15 times higher in July compared to the previous year.
Peter Daly, a biological sciences technologist at the City of Edmonton, noted that while these mosquito numbers were not record-breaking for the region, they marked a substantial contrast to the past two summer seasons, potentially influencing public perception. Similarly, Saskatoon and Winnipeg reported elevated mosquito counts in July compared to the previous year.
Experts in southern Ontario attributed the persistent mosquito presence to the record rainfall witnessed in parts of the region this summer. Fiona Hunter, a professor specializing in medical and veterinary entomology at Brock University, highlighted the prevalence of the Ochlerotatus trivittatus species this year. This floodwater mosquito thrives in water-filled low-lying areas, benefitting from the abundant rainfall in southern Ontario.
The species’ persistent biting behavior has led to increased human encounters, contributing to the perception of a worse-than-usual mosquito season. Rosalind Murray, an assistant professor of biology at the University of Toronto, suggested that the heavy rainfall triggered the hatching of dormant mosquito eggs, leading to a temporary population surge.
As temperatures drop, mosquito populations are expected to decline. Colder overnight temperatures are detrimental to mosquitoes, causing them to dry out and perish. Observations in Alberta following a cold snap indicated a significant decrease in mosquito numbers. Despite a warm fall in Edmonton, a decrease in the dominant local mosquito species, Aedes vexans, has been observed, with the possibility of resurgence as temperatures rise. However, the region is unlikely to experience mosquito populations as high as central Canada.
