Decrease in Mosquitoes

Observation by Emily Lanni:

I have noticed a marked decrease in mosquitos around my property and neighborhood over the last two to three years. I have lived on the same property for nine years, and in the past I can remember very intense mosquito activity it the early spring and moderate activity throughout the summer. There were years when we didn’t spend much time outside in the evenings when it started to get cool because once the mosquitos started to swarm it was pretty unbearable. In the last few summers however, it seems there have hardly been any mosquito swarms around. I see them occasionally, but never enough to be a bother. Early this spring there were a couple weeks when the were quite active and that's what really made me realize what a change there had been, because it struck me that this used to be a regular event and that I couldn’t remember the last time they had been that thick. After a couple weeks the activity died down and I hardly saw any for the rest of the summer. We have cleared a significant amount of trees and brush around our house over the last several years so that may be part of the reduction in our direct area, however we frequently walk pretty far down small trails in the surrounding woods and there are notably less mosquitos out in the trees as well. We are about 20 miles out of town and there is little to no development in the area so it doesn’t seem as if human activity in the area could be directly disrupting them.

Comments from LEO Editors:

Mosquito abundance in Alaska isn't well understood. There are 35 species of mosquito in the state belonging to two genus: Aedes and Culiseta. Species of both genus overwinter their eggs, but only Culiseta overwinter as adults in leaf litter or tree bark- emerging in the spring as the larger, slower, first-wave mosquito we're all familiar with. There are several factors that influence mosquito survival: snowpack and spring weather conditions. According to the Alaska Department of Environmental Conservation (see the Alaska Mosquito and Biting Fly Pest Control Manual in the documents section of this post), adult mosquitos hibernating over the winter require insulation from snowpack to survive the season. Mosquito eggs are not vulnerable to fluctuations in snowpack, but according to the University of Alaska Fairbanks Geophysical Institute, they are sensitive to spring weather - warm temperatures with average precipitation in April and May, followed by a dry spell in June, is ideal for mosquito survival.

During the winter of 2019-2020, weather stations at the Fairbanks International Airport measured above average snowpack which may have insulated mosquito eggs. However, despite fairly warm temperatures in April and May, a prolonged rain event in June may have reduced populations. Erica Lujan