When we return to the honey house we went though the various dead outs to discover the reasons for the losses.  Dead outs are when the bee colony dies leaving just the empty hive behind.  There are a few reasons for a hive to die over the winter; varroa mites, starvation, dysentery or becoming queenless.

     The varroa mite almost always attack a healthy hive. In the autumn the queen bee lays less eggs which allow the varroa mites to overwhelm the bees killing the hive.  Last winter 2021 - 2022, according to the Ontario Beekeepers' Association there were major winter losses due to varroa mites.  With some beekeepers reporting losing 90% of their hives.  According to Paul Kelly, head of the Honey Bee Research Centre and Apiary Manager at the University of Guelph, "Last year, spring (2021) came early, which is good for the bees - but also favourable for the varroa mites, which were able to start reproducing early.  The earlier the spring is the more reproductive cycles there mites can go through.  its like exponential growth."  Varroa mites are small parasites that attach to the back of the bees and feed off the bee's hemolymph (blood) and fat bodies.  Varroa mites can cause a number of debilitating viruses in bees.  Deformed wing virus is an RNA virus that attacks the development of the bee especially the wings and abdomen.  This shortens the life span of the bee greatly and making the bee unable to fly or do her other jobs.  Varroa mites like to attack strong healthy hive into a mite bomb. A hive that is a mite bomb will decline.  When the hive is in decline other bees from different hives will come into the hive to steal the honey.  While robbing honey, a varroa mite will attach herself to a bee and enter a new hive.  Varroa mites can hitch a ride from a worker or drone bee allowing infestations of various hives.  Once inside the hive the varroa mite can smell the bee larvae, and heads straight to the nursery.  The varroa mite enters an uncapped brood cell, and after the cell is capped, it will lay a male egg.  Then every 30 hours after the first egg a female egg is laid.  When each female mite matures it mates with its brother.  By time the brood cell is uncapped and a bee emerges so does three mated female mites.  Varroa mites cause malformations such as Deformed Wing Virus, other can transmit numerous viruses and weaken the bee's immune system.

     Starvation occurs when there was not enough food in the hive over winter.  This may happen because there was not enough food in the first place.  But also, may be the result of the cold weather.  Like all living things, bees turn food into energy.  When it is colder outside,, the bees cluster closer together and shiver to produce heat.  The colder the weather the more the bees need to eat in order to stay warm.  One colony can eat 30 pounds of honey over a single winter.  Or perhaps, there may have been a small cluster of bees going into the winter.  The bees are incapable of breaking apart from the cluster because of the need to stay warm.  So, the bees cannot get to the foos stores.  The winter food stores can also be contaminated by pesticides.

     Dysentery, were talking bee diarrhoea, an kill bees.  Bees hold their feces during the winter and when the temperature is over 10 C the bees going on cleaning flights.  The cleaning flights are their bathroom breaks.  Bees are capable of holding between 30 to 40 % of their body weight in addition feces.  Which is an amazing amount.  If the weather is too cold for too long, this can cause bees to have to go inside the hive, causing dysentery.  This type of dysentery is not contagious because it is due to weather.  But Nosema is a spore forming parasite that attacks the linging of the mid-guts of bees.  The spore feed on the lining if the mid-gut.  The mid-gut is less capable of digestion and absorption of pollen.  Unable to properly take in food weakens the bees.  A bee with dysentery life span is reduced by 78%.  If the queen gets dysentery, it will cause a drop in egg production and a high number of eggs will not become bee larvae.

      There can be many reasons a hive becomes queenless. A late autumn swarm, the original queen left the swarm and the new queen didn't take to the hive.  There is a number of reasons a new queen doesn't take to a hive.  She may not have mated; or she may have been eaten by a bird or other insects; or even met her end by meeting a car windshield.  The queen may have died without a new queen to replace her.  It could be a result of pesticides effecting the fertility of the queen.  Sometimes when a hive is left queenless  worker bee will step up to the job.  The problem is that worker bees never mate with drone.  If an unfertilized egg is laid, it will always produce a drone (male) bee.  Only fertilized eggs become workers bees.  The female bees are nurse bees taking care of the larvae, they bring the nectar and pollen back to the hive to produce honey, bee bread and royal jelly.  The worker bees even guard the hive.  The drone bee job is to mate with the queen to produce more workers.  Without a queen bee for the drone to mate there cannot be any more worker bee and the hive dies.

     No matter what the reason, every beekeeper tries to bring healthy hives into the spring.  But every beekeeper knows there will be some losses.  Some years there are few losses and some years there are great many loses.  Last year a number of beekeepers in Ontario had varroa mites distroy their bee hives.  Fingers crossed this will be a good year for beekeepers.

          Ontario beekeepers report 'heartbreaking' colony losses due to varroa mites Paula Duhatschek · CBC News · Posted: Apr 26, 2022 5:00 AM EDT | Last Updated: April 26, 2022