If we are to remain a beekeeper, then it becomes part of our mentality to accept the loss of hives. BUT like all things in life we should not merely take out the towel but engage our critical thinking to discern the cause. Not only will we become a better beekeeper but others may learn from our experience.
All too often we see the dead bees and ‘assume’. I came across an article – Death of a Hive Post Mortem Analysis from an avid beekeeper who relates her community sprayed Duet to reduce or eliminate the mosquito population. Shortly thereafter her hive died. But she went another step sending a sample of bees to USDA Lab in Maryland. It took six weeks for the results, but to her surprise the result came back with no disease but a mite count of 27%.
When reviewing a ‘dead out’ hive I would suggest having a buddy along for that second set of eyes.
Hive Body Weight
How heavy were your brood boxes going into winter? Did the bees have enough resources to make it through winter? In Minnesota, we build up our colonies into 3 deeps and leave 75-100 lbs. of honey for the bees to make it through winter and 3-5 frames of pollen to give the bees enough protein to begin raising brood in February.
Where are the bees? On a frame in a huddle? Only on the bottom board? None in the hive?
Did you measure and keep notes on the bees’ varroa mite numbers throughout the season? In particular, what were your mite numbers going into winter? If they were high (greater than 3%), did you do something about it? Mite counts should be less than 1%. (treat with a miticide/acaracide, remove capped drone comb, brood break, etc.)? Did you treat soon enough in the season so the treatment or intervention had time to work according to the label, or to do some good?
Varroa mites have killed your hive if you see lots of bees with deformed wings and short abdomens and lots of varroa mites on the dead bees, brood, and bottom board. Also look for tiny holes in brood cappings.
A recent visit to Clark County apiary found one beekeeper, with 50 years experience and 200 hives, who harvested his honey in July and treated with Oxcilic Acid July 15th and monthly thereafter. “Get them early”. He lost 2 hives out of 200 this past winter.
Is there honey? Is there pollen? Is the honey close to the huddle? Bees do not move during the cold wet winters we have. They form a ball, typically in the center of frames (4-5-6 of a 10-frame or 3-4-5 of an 8-frame) in the upper brood box for warmth. If your honey is on frame 3 with no honey on the central frames, the bees will starve. Before winter begins, realign your frames in the upper box with full frames of honey in the central position.
Is there brood? Capped? Open? Signs of an active Queen comes down to the laying of eggs. Remember your Queen should be producing 1500-2000 eggs per day during the spring/summer months.
Hives lost to Nosema have symptoms of acute dysentery. Often there is excessive bee excrement on the inner cover, top bars and front of the hive near the entrance(s). There are usually a handful of bees remaining that appear bloated and wet.
Hives lost to Nosema ceranae often have a small cluster and a small patch of brood located directly under the top bar of the upper hive body. In northern climates there is associated dysentery and an absence of significant numbers of dead bees on the bottom board.
Moldy frames? Evidence of cold and the lack of thriving bees to warm the interior. Mold is not bad, remove the dead bees, the new bees will clean up the mold.
Is there an odor? Foul Brood
Starvation signs include bees with their heads tucked into comb in search of absent honey and a lack of honey within two inches of the remains of the cluster.
Pesticide or chemical poisoning results in dead bees in front of the hive with their tongues sticking out.