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ARS Home » Pacific West Area » Tucson, Arizona » Honey Bee Research » Research » Research Project #437231

Research Project: Developing Best Management Practices for Overwintering Honey Bee Colonies in Cold Storage: Determining Optimal Colony Size and Timing

Location: Honey Bee Research

Project Number: 2022-21000-020-02-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jan 1, 2019
End Date: Dec 31, 2019

Objective:
Our goal is to develop Best Management Practices for beekeepers that overwinter hives in Cold Storage (CS). In the first year, we will determine if there is an improvement in colony population sizes before and after almond pollination between hives put into CS in either October or November. The Goal for the first year will be accomplished by completing the following Objectives. Objective 1. Identify hives that will have sufficient populations for almond pollination in February based on colony size and mites per 100 bees in September. Objective 2. Determine if colonies placed in CS in October have equal to or larger populations immediately before and after almond pollination compared with those placed in CS in November. Objective 3: Determine if bees in colonies placed in CS in October have more nutritional stores prior to and after CS compared to colonies placed in CS in November.

Approach:
Objective 1. Identify hives sufficient for almond pollination in February based on colony metrics in September. Colonies will be inspected in the first week of September, and frames of bees (FOB) and mites per 100 bees (mites) will be determined. Based on our decision tool for colony selection (Fig. 1), we will select two sets of 150 colonies, each with three groups with a high (0.8-0.9), medium (0.79-0.6), or low probability (0.59-0.4) of being >6 FOB in February (N=50 colonies/group). One set of 150 colonies will be placed in CS in October and another 150 colonies in November. When the hives are removed from CS and are in California, populations will be measured and actual numbers of colonies with >6 FOB will be compared with predictions. Objective 2. Determine if colonies placed in CS in October have equal to or larger populations before and after almond pollination compared with those placed in CS in November. Colonies will be removed from CS in late January and taken to California almond orchards. When the hives arrive in California, those put in CS in October and those in November will be assessed for FOB, brood, and mites. Colony sizes will be compared between the two groups to determine if FOB and brood differ depending on when the hives were put in CS. The percentage of colonies that are >6 FOB and suitable for almond pollination will be compared for the two groups. Colony measurements will be taken again when almond bloom is over. FOB and brood will be compared using a two-way ANOVA with time when they were put into CS (October or November) and probability group as factors in the model. Objective 3. Determine if colonies placed in CS in October have more nutrient stores prior to and after storage compared to colonies placed in CS in November. Colonies destined for CS in either October or November will be sampled three times: in September for baseline measurements, after removal from CS in late January, and after the almond bloom. 80 focal hives from Objectives 1 and 2 will be chosen at random, 40 from the October CS treatment (20 high/20 low probability) and 40 from the November CS treatment (20 high/20 low probability). At each sampling event and for each hive, 50 bees will be collected from the brood area. The abdominal carcasses of 30 of these bees will be dissected, pooled by colony, dried, weighed, and assayed for lipids and proteins. The heads from these same bees will be dissected, pooled by colony, dried, weighed, and assayed for protein content. For each colony within each treatment (high and low probability groups (2) x 20 colonies per group x 2 CS regimes = 80 colonies) and for each of the three time points, abdominal weight and nutrients, head weight and protein will be measured. We will analyze each response variable with respect to the CS treatment (October vs. November) and express the data as fold difference from the September sampling event prior to CS. Probability group will be nested within CS treatment.