We believe there to be two possible causes for this loss. The first was related to the temperature. It went from near 60 degrees to the 30’s overnight, which may have caught the bees by surprise since they break cluster when the temperature rises. The second possibility was the low lying fog the morning following this drop which could’ve caused the bees to get too damp. Cold weather should not be a problem for the bees as long as they remain in cluster and keep the hive about 92 degrees. Moisture is a much bigger danger for the bees because the bees need to stay dry.
Colony Collapse Disorder would be one possibility of the loss, but this would result in the adult bees leaving the hive. The bees were found in the hives. Some were found still clustered, some were found away from the cluster, and many were found dead in the bottom of the hives. The bee bodies were wet. It is not known if they got too wet from the fog and died or if the bodies became moist after they died.
We received information from the National Corn Growers Association (NCGA) about an organization that performs laboratory testing on bees. We proceeded to send off a sample of our bees to this organization, the National Agricultural Genotyping Center (NAGC), for testing. The bees were tested for 11 pathogens, and none of these pathogens were found. This helped us narrow down what we believe to have caused the deaths and determine that is was most likely caused by the unusual weather pattern.
Each year is a unique learning experience. The decision was made to repopulate our hives following this complete loss and take what we learned and forge ahead to make the strongest and best hives we can.
Sources:
https://beeinformed.org/2017/05/26/preliminary-2016-2017-state-total-and-average-losses/
