Progress report for FNE24-101
Project Information
With this project we will evaluate the effects on colony performance of feeding sugar syrup with bleach, sugar syrup without bleach, and no supplemental sugar syrup at all. We will compare:
- Colony population growth: compare total number of frames of brood between experimental groups
- Colony weight gain: compare weight gain between experimental groups
- Rate of consumption: compare consumption rates of sugar syrup between experimental groups
- Brood pattern: compare brood patterns between experimental groups
- Microbial growth: compare presence of black mold in feeder jars between experimental groups
- Remunitive advantage: calculate and compare cost of bleach with colony performance
- Nosema levels: compare levels of Nosema ceranae between experimental groups
- Winter Survival: compare winter survival rates of colonies between experimental groups
Beekeepers in the Northeastern U.S. experience on average 40% colony losses through the winter period annually. This high winter loss rate has resulted in decreased honey production and overall fewer colonies in the country, all while the demand for agricultural pollination services is increasing. To replace these high winter losses and to meet the demands of modern agriculture, beekeepers typically make more honey bee colonies (nucleus, nucs, or nuclei) in the spring and summer by splitting one colony into two or more colonies. It is standard practice for beekeepers to feed these nucleus colonies sugar syrup to make up for these high winter losses and to help lessen the stressors that honey bees are facing. Making strong and healthy nuclei is a cornerstone of sustainability in beekeeping. These nuclei are made not only to replace winter losses, but also to sell to other beekeepers. Nuclei are also made for the purpose of queen production, and these are called mating nuclei. Mating nuclei typically require feeding because of their smaller populations. Due to unpredictable weather, climate change, pests and disease, and decreased pollinator habitat, these newly formed colonies are typically fed sugar syrup prepared by the beekeeper to ensure they have adequate nutrition. The most commonly mixed ratio of sugar syrup for feeding during this time of year is referred to by beekeepers as 1:1. The sugar syrup is prepared by mixing one part sugar (sucrose) with one part water by weight.
One of the most common methods of feeding is done by inverting a container of sugar syrup over the colony. The bees can access the inverted sugar syrup feeder from the colony via a hole in the lid of the hive. The sugar does not spill out into the colony because of a vacuum which is formed inside of the container, allowing the bees to use the sugar syrup on demand. The sugar syrup is used inside the colony like nectar would be used. Nectar is the carbohydrate source for honey bees, and is produced by flowers to attract pollinators. Incoming nectar from the field, or in this case from a feeder, stimulates the bees to rear young (brood) and to build comb, with the ultimate result of the colony gaining weight and increasing its worker bee population. If more nectar is coming into the colony than is needed, the bees will dehydrate it and store it in their combs as honey.
A very common observation beekeepers have when implementing the management practice of feeding 1:1 sugar syrup is the formation of black mold inside of the feeders. To combat the formation of black mold, beekeepers have attempted to incorporate various additives into the sugar syrup. One of the most promising additives to prevent black mold growth anecdotally observed by beekeepers is common household bleach. This is added at a rate of 1 teaspoon per gallon of sugar syrup. It has been observed by many beekeepers that this addition of bleach does in fact prohibit the formation of black mold inside the feeding jars. Since black mold would presumably not have the opportunity to form naturally in the nectar of a flower, the consumption of it by the bees via the sugar syrup may be detrimental to their health. By adding bleach to sugar syrup with the intent of preventing black mold, colony health may be able to be improved. However it is not known if there are any detrimental effects from the addition of bleach.
With a potentially improved mold-free sugar syrup, colonies may grow more quickly and nuclei would therefore be ready for sale sooner and would increase the profitability of beekeeping operations. This could also lead to increased honey production, as beekeepers could still make nuclei to replace their winter losses, and potentially have them ready in time to produce honey. And with the constant demand for strong, healthy colonies to perform pollination services, this could mean more colonies who fit the bill. Stronger and healthier mating nuclei would also make queen production more profitable.
Another stressor faced by honey bee colonies which impacts the profitability of beekeeping operations is the disease Nosematosis, caused by the microsporidian Nosema ceranae. This disease decelerates colony growth, resulting in weak colonies that do not produce as much honey or bees. Transmission occurs via ingestion of spores in the feed and by trophallaxis. A germicidal sugar syrup may prove to be of value in preventing this disease (Galajda et al, 2021).
Cooperators
- - Technical Advisor
Research
A total of 42 colonies were dedicated to this project. The 42 colonies were randomly assigned to three experimental groups, each consisting of 14 colonies. The sugar syrup with bleach experimental group was fed 1:1 sugar syrup with bleach added at a rate of 1 teaspoon per gallon of sugar syrup. The regular sugar syrup experimental group 2 was fed 1:1 sugar syrup with no additives. The control experimental group received no supplemental sugar syrup feeding. The experimental groups were divided evenly between two separate apiaries in Northwest Pennsylvania. The two apiaries were located approximately 4.80 miles (7.75 km) from one another. Both apiaries were positioned in full sun locations, with naturally occurring windbreaks to the north and west. On June 16th 2024, 21 colonies were formed and were used to establish the first study apiary. On June 18th 2024, another 21 colonies were formed and moved to populate the second apiary. The colonies were formed with two frames of brood (one frame of actively emerging brood, the other of open brood), one frame of resources, and a frame of undrawn foundation. Upon arriving to the study apiary, each colony was given a mated queen. All of these queens were produced from the same queen mother, so as to be as uniform as possible. The protective cap was left in place on the queen cage. Returning 5 days later, respectively, all emergency queen cells were destroyed and the queen candy was exposed. Even though this method of queen introduction requires a second visit to the hives, it resulted in a 100% queen acceptance rate. This was crucial to the experiment as it created a level playing field for all colonies. The colonies were fed using 1/2 gallon jars, with three 1/16" holes drilled in the lids. Each apiary was subsequently visited every two weeks. At each visit any remaining sugar syrup was measured using a graduated cylinder to determine the rate of consumption, and the presence of black mold inside of the 1/2 gallon jars was assessed. All colonies were then weighed using a digital scale. Next, the colonies were inspected to measure the number of frames of brood and queen laying pattern. The number of frames of brood was measured in 1/4 increments. Queen laying pattern was scored on a scale of 1-3, with 1 being a poor pattern, and 3 being an excellent pattern. Samples were taken three times from each colony during the course of the study for Nosema quantification. A 1/4 cup sample of bees was taken from each colony, and placed in isopropyl alcohol. More boxes were added to the colonies as needed. The 1/2 gallon feeders were filled at each subsequent visit for experimental groups 1 and 2. The number of living colonies was recorded at the end of October, and will be compared to number of living colonies in April so as to ascertain winter survival for the experimental groups.
The number of frames of brood in each colony was measured six times in two week intervals. The sugar syrup with bleach experimental group (Bleach Group) averaged roughly two more frames of brood than the control group (Control Group), and roughly one more frame of brood than the regular sugar syrup experimental group (Regular Group). The Bleach and Regular groups both consistently had increasing number of frames of brood, whereas the control group actually saw a decline in the number of frames of brood. This downturn in brood production by the control colonies was caused by a nectar and pollen dearth that we typically experience in July in northwestern Pennsylvania. Aside from the apparent benefits of bleach in sugar syrup for brood production, this data also highlights the importance of beekeepers ensuring their colonies have adequate nutrition during times of resource scarcity. Sugar syrup with or without bleach added is better than none during the dearth period, and prevents the colonies from experiencing stunted growth.
The weight of each colony was measured six times in two week intervals. The Bleach Group weighed on average roughly 4 kg (8.8 lbs) more than the Control Group, and roughly 1 kg (2.2 lbs) more than the Regular Group. Once again, the Control group saw a downturn during the Pennsylvania dearth period and lost weight during it. This data again highlights the importance of beekeepers feeding colonies during the dearth period to prevent backsliding. At the end of the study, the Bleach Group on average weighed 37.5 kg (83 lbs), the Regular Group on average weighed 35.8 kg (79 lbs), and the control 25.8 kg (57 lbs). In some regions of Pennsylvania there is a large amount of nectar available to the honey bee colonies in late August and September from goldenrod (Solidago spp). The Bleach and Regular groups were in better condition to take advantage of this nectar flow because of the supplemental feeding they received, and as a result, made more goldenrod honey. This should greatly increase the winter survival chances for the Bleach and Regular Groups. This also suggests that beekeepers in the northeastern US region wishing to get a late season honey crop should consider feeding their colonies during the resource dearth to ensure their colonies are in optimal condition to make honey.
Rate of consumption of sugar syrup was measured six times in two week intervals. There was no observable difference in the rate of consumption between the Bleach and Regular Groups. This was due the the two week measurement interval being too long, and all sugar syrup was gone from the 1/2 gallon jars at each visit. To measure the rate of consumption in future studies, the measurement interval should be drastically decreased to potentially every day in order to obtain meaningful data.
Brood patterns were assessed six times in two week intervals. The Bleach and Regular groups consistently had better brood patterns, with the average being 2.86 and 2.85, respectively. For the control group, the average brood pattern was 2.59. The resource dearth once again caused a decline in performance for the Control group. Without supplemental feeding, the Control group experienced deteriorating brood patterns during the resource dearth because the colonies were nutritionally stressed. Inadequate nutrition can lead to malnourished brood and less of it, decreasing the value of the colony.
The feeder jars were observed at each visit for the presence of black mold growing inside of the jar. No black mold was found until 7/14, one month into the study, when it appeared in all of the feeding jars. Although black mold was present in the feeder jars that had bleach added to the syrup, there was significantly less of it compared to the regular sugar syrup feeder jars. Most of this first flush of black mold was found towards the lid side (bottom, when inverted for feeding) of the feeder jar. Upon returning two weeks later, the black mold growth had continued inside of the regular sugar syrup feeder jars and was present in most jars from the top of the sides to the lid (bottom). Inside of the bleach sugar syrup jars mold growth was almost non-existent, and was still only present towards the lid side (bottom) of the feeder, with mold growth occurring on the side walls in a few cases. During each subsequent visit, the Regular sugar syrup feeders continued to experience black mold proliferation. The black mold that developed in the Bleach sugar syrup feeder jars did not progress much past the initial colonization for the remaining duration of the study.
Nosema samples are still being processed, and the full data set is not ready at the time of writing this progress report.
Winter Survival comparison between the experimental groups will not be known until April of 2025, and can not be reported on at the time of writing this progress report.
