Mosquitoes Multiply in Car Tires, But Few Seen in Southern Finland Yet

Residents enjoying the summer in southern, central, and eastern Finland might have noticed a distinct lack of itchy mosquito bites. Professor and insect researcher Marko Mutanen reports that mosquito populations are unusually low in these regions.

While a mild winter and dry spring are often blamed, Mutanen explains that other factors significantly impact mosquito numbers. These include their own diseases, predators, and various environmental influences that are not yet fully understood. The location where mosquitoes lay their eggs, particularly the availability of moisture, also plays a critical role.

Summer mosquitoes, the species most bothersome to humans, lay their eggs in damp soil or very wet areas like ditches and bogs. Ponds and lakes are unsuitable because fish would consume the larvae. The eggs can lie dormant for at least a year, waiting for a suitable puddle to form. In very dry springs, these eggs might wait underground for several years. "A mosquito can reproduce even in a car tire if there's enough water," Mutanen notes.

Therefore, the low numbers observed over one or even a few summers do not indicate that mosquitoes are disappearing. "Mosquito numbers fluctuate, and long-term trends cannot be predicted." Mutanen adds that if Finland's climate were to become more like Central Europe's, with more evaporation than rainfall, mosquito populations could decrease, but scientifically verifying this would require slow, long-term monitoring.

Reports from areas like Åland and the Oulu region indicate "commendable" mosquito numbers, while Lapland has experienced a potentially more abundant mosquito season than usual. "The mosquito season will continue for some time. Their numbers might even increase." Despite the annoyance of buzzing and itching, mosquitoes play a vital role in the ecosystem, serving as food for birds, dragonflies, and bats. "Removing any part might not collapse the entire ecosystem, but it would cause a disruption," Mutanen cautions.