Big year for some biting insects, but not mosquitoes

Observation by Wilson Justin:

There were more bugs and insects then ever but few mosquitoes. The mosquitoes were out early in May but never showed in force as expected. The gnats, no see ums, white sox and several other unidentified bugs on the other hand were relentless. Walking around the yard after a rainfall was a study in being swarmed.

Comments from LEO Editors:

This is the second post LEO has received about low mosquito abundance during 2020 - another observer in Fairbanks also commented on declining mosquito populations. Mosquitos are sensitive to changes in snowpack, precipitation, and temperature, depending on their lifecycle stage.

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 and emerge in the spring. 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. Low snowpack may mean a higher adult mortality and fewer of the large mosquitos seen in early spring. Mosquito eggs are not vulnerable to fluctuations in snowpack, but do require either permanent standing water or flood water to hatch in the spring. According to the University of Alaska Fairbanks Geophysical Institute, young mosquitos are also sensitive to spring weather, preferring warm temperatures with average precipitation in April and May, followed by a dry spell in June.

No-see-ums (of the genera Culicoides and Leptoconops) and white sox (black flies in the Simulid family) also hatch in environments that are moist or that become flooded in the spring. Some white sox species produce only one brood a year, emerging in spring and summer, while other species may produce multiple broods near warmer streams and creeks.

The weather station at the Gulkana airport did not record snow depth this winter, but did record temperature and precipitation. Spring temperatures were warm, with some days in May reaching nearly 75 degrees. Gulkana did receive more precipitation than usual with significant rainfall in mid-late May, and continuing in to June. Erica Lujan