Hi Mr. Ben.
You have an interesting observation. I have one concern: wax moths fly at cooler temps than bees. So the concern is moths fly into a hive with excess, unguarded space and lay eggs in the wax. This is the reason beeks don?t like excess space during winter.
However, in your case a positive result incurred. So this begs the question: what is the actual low temperatures that wax moth fly? Anybody know, I do not. Member, your needed here!
I found this on Honey Bee Suite: "Contrary to popular hearsay, freezing will kill all life stages of both the greater wax moth (Galleria mellonella) and the lesser wax moth (Achroia grisella).
To kill the moths, you must monitor both time and temperature. For example, the Mid-Altantic Apiculture Research and Extension Consortium (MAAREC) publishes the following guidelines to kill both species of wax moth:
20 degrees F for 4.5 hours or
5 degrees F for 2 hours."
Just a guesstimate from those numbers, but I'd think that at around 32 F for 12-24 hours would probably do it too. Above freezing it's difficult to say. I couldn't seem to find anything on that. I don't know, but I can't see adult moths flying outside the hives in any temps we'd call cold. Unless they have some way to heat themselves up (like bumble bees for example) I don't know how they'd be able to operate in cold temps since they are cold blooded. The issue is that the bees keep at least their area of the hive warm, so if there are any wax moths eggs, larva, or adults that survive near the cluster, when it warms up they could easily move up into the empty boxes. I wonder if the crazy cold snap that you had, Phillip, contributed to keeping the wax moth numbers down.