Winter is coming: Improving overwintering survival of honey bee colonies in Pennsylvania

2016 Annual Report for GNE15-100

Project Type: Graduate Student
Funds awarded in 2015: $14,940.00
Projected End Date: 12/31/2016
Grant Recipient: Penn State
Region: Northeast
State: Pennsylvania
Graduate Student:
Faculty Advisor:

Winter is coming: Improving overwintering survival of honey bee colonies in Pennsylvania


In this project, I aim to increase overwintering success of honey bee colonies by co-opting the social regulation of their transition to overwintering phenotype. For this purpose, first I will examine effects of pheromones on the timing of winter bee production and size of winter bee population through fall and winter of 2016, and then I will compare health, performance and overwintering success of manipulated and non-manipulated colonies. Finally, using the results from the first (i.e. 2016 – 2017) winter in this study, I will develop a pheromone treatment program and partner with beekeepers to test this treatment program in real life conditions in the second (i.e. 2017 – 2018) winter. Findings will be disseminated beekeepers and commercial bee breeders.

Objectives/Performance Targets

Objective 1. Test the effects of two honey bee pheromones, forager pheromone and brood pheromone, on timing of winter bee production in fall and size of overwintering population in honey bee colonies.

Objective 2. Determine the effect of different pheromonal treatments in fall on colony health (colony weight, colony size, storage levels, virus and parasite loads) and overwintering survival.

Objective 3. Using the results from Objectives 1 and 2, develop a pheromone treatment program to improve overwintering success in honey bees, and partner with beekeepers to test this treatment program in real life conditions.

Objective 4. Disseminate the results from Objectives 1 and 2, and the treatment program developed in Objective 3 to beekeepers and commercial bee breeders.



In 2016, I ordered colonies and necessary equipment for the experiments, and installed them in our apiaries near Penn State. Standard beekeeping practices were followed through Spring and Summer of 2016 to prepare the colonies for experimentation that took place in Fall. At the end of Summer, I equalized colony size and weight to eliminate the effect of initial colony size in future assessments we had planned.

Objective 1. September to November every two weeks, I collected worker brood from the colonies, allowed them eclose in incubators, marked and returned them to their colonies in order to establish color marked cohorts of known age and eclosion time. Unfortunately, we had unexpectedly high death rates in the first cohorts upon re-introduction as well as loss of markings even though the marking method – enamel paint on thorax – was a method I have used in the past and is extensively used in honey bee research. Ultimately, we are left with two cohorts of worker bees that can be accurately investigated for winter survival at the when the colonies are re-examined in Spring 2017. This last part of the Objective 1 is not fulfilled at the moment.

Objective 2. During Fall 2016, I also applied pheromones to assigned colonies and recorded (every two weeks, as in Objective 1) several measures of colony demographics and strength such as weight, population size, brood area, and honey and pollen storage in order to assess the effect of pheromone treatments on the colonies. This objective will be completed in Spring 2016, as soon as I the weather allows proper assessment of the colonies. Our preliminary findings show little to no effect of pheromone treatments on measured variables in this project this far. However, complete data set with survival information still has potential to prove treatments effective. This, we will learn in 2017.

Objective 3. This objective cannot be achieved until the data collection from previous objectives are complete.

Objective 4. In order to disseminate the results from Objectives 1 and 2, I have presented my findings to this point in the project to beekeepers and researchers as a poster in Pennsylvania State Beekeepers Association Annual Meeting in State College, PA (November 11-12, 2016). Many beekeepers engaged with the presentation and I had the chance to not only explain the details of the project to them but also get excellent feedback and ideas on how to move on from here. I also got accepted to the American Bee Research Conference in Galveston, TX (January 12-13, 2017) for an oral and a poster presentation where I will have the opportunity to engage with a much broader audience.

Impacts and Contributions/Outcomes

With this project, I aim to provide beekeepers a novel method to support the colony’s natural efforts to prepare for winter, and thereby improve overwintering success. Overwintering losses threat sustainability of beekeeping operations and reducing winter loss will bring a positive change to the dynamics of the pollination services market; and due to increased supply, cost of pollination services to the farmers will be reduced while beekeepers will remain profitable, possibly more than at present.


Dr. Christina Grozinger
1A Chemical Ecology Lab
State College, PA 16802
Office Phone: 8148652214