This picture was taken on February 19, 2014, the second day of 40ºF weather here in southern Wisconsin. The picture shows a lot of dead bees and yellow spots in the snow where the bees pooped. The question is should I be concerned or not?
I went to the hive to give the bees a sugar patty, in case their food supplies were running low and a Fumaglin treatment for the prevention of Nosema*. You normally don’t open a hive unless it is 50º F but it has been an extremely cold winter with 35 days at or below zero degrees and daytime highs staying well below the freezing mark. We normally experience an occasional warm up that allows the bees to get out for their “cleansing flights” and perhaps get some pollen but not this winter. The forecast was for more cold weather so I thought I should go ahead and treat the hive and give them some sugar while I had a chance.
The picture shows several dead bees in the snow. While this is a concern, it is somewhat expected and can be interpreted as a positive sign as it shows your colony is still alive. The normal life expectancy of a worker female bee during the summer is about 5 ½ weeks, but in the winter they can live for up to three months,with their duties being reduced to tending to the hive and forming a cluster around the queen to keep her and the colony warm. So even with their longer winter lifespan you still expect many to die, and they will leave the hive to do this so as not to burden their fellow sisters with having to deal with their dead bodies. As the weather gets colder they form a tighter cluster around the queen. The center of the cluster stays around 93º F, even if the temperature outside gets down to a minus 40º F, with the edge of the cluster averaging 50º. The bees take turns being at the edge of the cluster.The heat is generated by shivering, using the same muscles used for flying, but the wings don’t move. Honeybees are the only insects in the Northern Hemisphere that stay active and heated up throughout the northern winter.
Initially I was glad to see the yellow stains as it meant they were finally able to get out to relieve themselves, but the amount of poop in the snow and on the hive was a concern. Perhaps these were signs of dysentery or Nosema? When I got back to the house, I checked my bee books and on the Internet to see if I could find any answers to this question. What I found was inclusive. They might have dysentery or Nosema, or both, but it also might mean it had been a long cold winter and there was a rush to get out. If it is Nosema, hopefully my treatment was timely. I won’t know the final answer until spring. The day following this picture there was a rain storm that washed away the stains, and in the two days following the rain there have been no more stains in the snow and the hive seems healthy. So I am hoping for the best.
*Nosema is a disease caused by an organism known as Nosemaapis. Spores of the organism enter the body of the adult bee through food and water and germinate in their gut. Nosema is fairly common with honeybees and can cause extensive losses for adult bees and eventually the queen. The disease can be accompanied by dysentery caused by long winter confinement.