It's the facultative diapause season

Matt:

I have some friends who live in the Frozen North. They claim that when they close up all the windows for winter, flies collect on the window sill and lie dormant for the rest of the season. Then when they open the windows in spring, these same flies are revived and eventually fly away. Is this possible?

-- Bzzzzzzz, someplace warmer

So Buzz, I'll reserve comment on folks who leave comatose flies all over the window sills for an entire winter. Even a small effort with a Dustbuster, and I wouldn't have to waste my time answering this. Your friends would not know and you would not care that flies can doze away for months, then wake up fully refreshed. It's fully possible that your untidy Frozen Northerners have all manner of flies, mosquitoes, spiders, and other insects hiding in many cozy crevices inside and outside the house. The correct term for this midwinter nap is facultative diapause, a physiological mechanism for surviving under temporarily adverse conditions, like when you're freezing your wings off. Come to think of it, by that definition, sleeping through biology class is a sort of diapause too.