Hi again, Jennifer!
Thanks for the additional information, that is very helpful. It sounds like you did conscientious inspections during the season. So I would say the two most likely causes of your hive loss are varroa and starvation, in that order. It is possible that they absconded for some reason too, but in that case, the comb would not normally be empty unless it has been robbed.
So what do to this year? Well, this would be my tentative plan.
- Take the hive apart, if you haven’t already, and freeze all of the frames with wax in them for at least 48 hours. That will kill any wax moth and SHB larvae. If you have had a good freeze during the winter, you won’t need to do this.
- When your bees arrive, reduce the hive down to a single brood box. Put your new bees in this box, and do not add another box until all frames are fully drawn, plus they are 80% full of brood, honey or pollen.
- I would add a second brood box and let that get fully drawn and 80% filled before doing anything else. This will mean that your colony has good reserves for winter before you start sharing in the honey.
- Add the Flow super when both brood boxes are more than 80% full and every frame is covered with bees.
- Consider doing sugar roll (non-lethal and quite accurate) or alcohol wash (lethal but very accurate) counts for varroa thoughout the season. Treat if mite counts get worrying, or you see signs of viral diseases, including DWV. There are plenty of organic treatments if you want to stay as natural as possible, including MAQS and Oxalic Acid. Treating for varroa if needed will greatly increase the chances that your hive survives the winter.
- Carefully monitor food stores over winter, and feed if needed. One way to do this in cold weather is to learn to “heft” the hive. The best way is to get a hive scale and weigh the hive regularly.
I wish you better luck this year, and hopefully something from the above will be useful to you.