Robin,
What 'sugar'? Did you open the hive? Do you have a thermal gun/camera? That will tell you a heat signature even if you don't open it. Otherwise, if it gets into the 50's, you can do a very-quick pop-the-top-and-look. But, what can you do differently if they are there or not? I'd just leave it, wait for a warm day that you a do an exam. Put an entrance reducer to keep mice out. SHB/moths won't be a problem in the cold. If they have failed/absconded, save the frames for next time (freeze them for a couple of days). Beekeeping is a heart-wrenching activity. Sometimes we make the mistake, sometimes the colony just doesn't survive due to their own flaws. It happens. Keep in mind, 40%+ of colonies nationwide fail each year. Most BKers experience that over and over. My bees are just too mean to die like that. But most everyone can't or won't keep mean bees like mine.
What 'sugar'? Did you open the hive? Do you have a thermal gun/camera? That will tell you a heat signature even if you don't open it. Otherwise, if it gets into the 50's, you can do a very-quick pop-the-top-and-look. But, what can you do differently if they are there or not? I'd just leave it, wait for a warm day that you a do an exam. Put an entrance reducer to keep mice out. SHB/moths won't be a problem in the cold. If they have failed/absconded, save the frames for next time (freeze them for a couple of days). Beekeeping is a heart-wrenching activity. Sometimes we make the mistake, sometimes the colony just doesn't survive due to their own flaws. It happens. Keep in mind, 40%+ of colonies nationwide fail each year. Most BKers experience that over and over. My bees are just too mean to die like that. But most everyone can't or won't keep mean bees like mine.