Wintering bees

The stretch of winter without bees can feel lengthy. We readied our colonies in the fall for the long lean months of cold, and then had to leave them to do what they do. Do you see the winter months as a much deserved reprieve from the physical labor of bees and other outdoor work?  Has your attention turned to reading and contemplating about bees? Are you anticipating the arrival of catalogues with beekeeping equipment and botanical offerings? Are you patiently waiting for spring?

 

Our management mantra in the fall was:

A). Take winter losses in the fall (unite rather than rescue

B). Bees don’t freeze they starve (insure populous fall colonies with plenty of honey stores) and

C). Winter bees live longer than summer bees (bees need raise new workers who don’t need to work late into the fall feeding brood or foraging).

They are great conventions to talk about but are difficult to achieve.

Outside in those hive boxes the queen historically resumes laying eggs to start the bee season in January and depending upon the weather begins to ramp up in February.  Our winter brood monitoring at OSU illustrates this: [https://agriculture.auburn.edu/research/enpp/bee-lab/winter-capped-brood-monitoring/] . In the overwintering hives, the older winter bees will need function as nurse bees to raise this early brood. Making brood food uses up their vitellogenin (Vg) and fat body stores. The newly raised bees, better equipped with brood food glands, will then take over this task. The life of the winter bees raised last fall are numbered. Calendar winter/spring varies with location, elevation, etc.

 

Prior to brood rearing, the winter cluster keeps an internal cluster temperature between 60 and 70 degrees once brood rearing ceases in the late fall.  When the colony raises brood, they need to raise the temperature in the brood rearing area to around 90-95 degrees.  If you have a temperature probe in your hive, you will see the temperature start to rise above 70 degrees, which signals there is brood somewhere. It will take a few weeks before the amount of brood is large enough for the temperature sensor, which is often on the top edge of the colony, to read 92 degrees.

The winter cluster is most efficient at a temperature of 14◦F. Above this temperature, more stores are used as bees remain active. The honey stores run muscles. Fluctuating temperatures such as we experience mean periods of greater activity and a greater need to use honey. Below this temperature, bees cluster even closer. If there is brood, heater bees are needed to raise a small number of brood. Use of stores accelerates with colder temperatures, with or without brood to care for.

When there is a warm day above 55 degrees with little wind, you could quickly visually inspect a frame in the center of the cluster.  The risk of doing this is chilling the bees and chilling the brood; so make sure you do it quickly and pick a warmer day to do so. You should see a typical frame arrangement of brood centered with a mantle of bee bread stores immediately above and capped honey in the corners and on edge frames further to the outside.  Pick up deadouts. Record your overwintering success as I will be asking you to again participate in the PNW honey bee loss survey – it opens in mid-March for you entering data. It ahs been streamlined this year to make it even easier to enter your information.

Colonies are at risk of starvation over the next 6 weeks.  Needing to feed brood and keep brood warm will increase consumption of their food resources.  You should be assessing the remaining winter store situation. Hefting colonies, looking quickly in the top, reading your sticky board or actually weighing colonies, especially any nucs you are overwintering to confirm they still might have adequate food resources. Until brood rearing starts weight loss will be minimal. Watch the weather as cool, wet springs increase the risk for spring starvation.