By: Max O'Grady
Figure 1 from Hepburn et al. 1991 Introduction
As an undergraduate student pursuing the Department of Entomology honors certificate, the central focus for my honors research project will be investigating what factors may influence wax production efficiency in honey bees. Effective wax production is an extremely critical part of a functioning honey bee colony, making it an important area to study. There have been studies done in the past to examine factors influencing wax production, such as individual bee age and seasonality. However, in my most recent experiments, I have been looking at an entirely different factor that seems to influence wax production: how many individual bees there are in a given volume. Since this is the first semester that I have been working on this project, I do have some preliminary data, but I have mostly been working on finalizing methods. Once I have all my methods and protocols finalized, I will be able to move on to examining how other factors, such as ambient temperature and the type of feed provided, influence wax production.
Background
Before examining what factors affect the efficiency of wax production, it is important first to understand the physical and chemical processes by which beeswax is produced. Beeswax is produced in the wax gland complexes of a honey bee’s abdomen. The wax gland complex consists of three cell types: epithelial cells, adipocytes, and oenocytes (Cassier & Lensky 1995). These three cell types work together to produce and secrete the hydrocarbons, fatty acids, and proteins that are present in beeswax. The adipocytes and oenocytes make up what is known as the fat body, and these cells produce the wax while the epithelial cells are mainly there to provide transport tubules for transporting the wax to the surface of the abdomen to be secreted (Hepburn et al. 1991). Honey is the main ingredient of wax that is digested in the fat bodies. The complex sugars of the honey get broken down into the basic carbon, hydrogen, and oxygen and are put back together as hydrocarbons and fatty acids (Winston 1987). Pollen is also important towards effective wax production because pollen is made up of vitamins, minerals, lipids, and proteins, which are all needed for proper wax gland development, and pollen provides more necessary ingredients for wax production (Winston 1987). According to an experiment done by Goetze and Bessling (1959), a controlled colony fed sugar and pollen produced more than nine times as much wax as a controlled colony that was just fed sugar.
As mentioned before, there have been studies that show certain factors that affect wax production. For example, Hepburn et al. (1991) it was concluded that the amount of wax produced by an individual bee is significantly affected by the age of the bee. In another study done by Pratt in 2004, it was shown that wax production can be influenced by the season and whether the colony needs more wax to accommodate events such as nectar flows or heavily laying queens (Pratt 2004). Hepburn et al. (2014) claim that wax production is also influenced by temperature because the comb-building area has to be warm enough, usually between 30-37°C, in order for the bees to be able to secrete wax scales and use them to build comb. My project aims to expand on the knowledge of factors that influence wax production, which would grant a more complete understanding of how we can better provide for bees to maximize their health and productivity.
As an undergraduate student pursuing the Department of Entomology honors certificate, the central focus for my honors research project will be investigating what factors may influence wax production efficiency in honey bees. Effective wax production is an extremely critical part of a functioning honey bee colony, making it an important area to study. There have been studies done in the past to examine factors influencing wax production, such as individual bee age and seasonality. However, in my most recent experiments, I have been looking at an entirely different factor that seems to influence wax production: how many individual bees there are in a given volume. Since this is the first semester that I have been working on this project, I do have some preliminary data, but I have mostly been working on finalizing methods. Once I have all my methods and protocols finalized, I will be able to move on to examining how other factors, such as ambient temperature and the type of feed provided, influence wax production.
Background
Before examining what factors affect the efficiency of wax production, it is important first to understand the physical and chemical processes by which beeswax is produced. Beeswax is produced in the wax gland complexes of a honey bee’s abdomen. The wax gland complex consists of three cell types: epithelial cells, adipocytes, and oenocytes (Cassier & Lensky 1995). These three cell types work together to produce and secrete the hydrocarbons, fatty acids, and proteins that are present in beeswax. The adipocytes and oenocytes make up what is known as the fat body, and these cells produce the wax while the epithelial cells are mainly there to provide transport tubules for transporting the wax to the surface of the abdomen to be secreted (Hepburn et al. 1991). Honey is the main ingredient of wax that is digested in the fat bodies. The complex sugars of the honey get broken down into the basic carbon, hydrogen, and oxygen and are put back together as hydrocarbons and fatty acids (Winston 1987). Pollen is also important towards effective wax production because pollen is made up of vitamins, minerals, lipids, and proteins, which are all needed for proper wax gland development, and pollen provides more necessary ingredients for wax production (Winston 1987). According to an experiment done by Goetze and Bessling (1959), a controlled colony fed sugar and pollen produced more than nine times as much wax as a controlled colony that was just fed sugar.
As mentioned before, there have been studies that show certain factors that affect wax production. For example, Hepburn et al. (1991) it was concluded that the amount of wax produced by an individual bee is significantly affected by the age of the bee. In another study done by Pratt in 2004, it was shown that wax production can be influenced by the season and whether the colony needs more wax to accommodate events such as nectar flows or heavily laying queens (Pratt 2004). Hepburn et al. (2014) claim that wax production is also influenced by temperature because the comb-building area has to be warm enough, usually between 30-37°C, in order for the bees to be able to secrete wax scales and use them to build comb. My project aims to expand on the knowledge of factors that influence wax production, which would grant a more complete understanding of how we can better provide for bees to maximize their health and productivity.
Figure 2 Experiments and Results
First Experiment
The first experiment I did this semester was focused on how having different numbers of bees in individual cage cups affects how many wax scales each bee produced on average, as well as how it affects any comb-building behavior within the cage cup. For my experimental setup, I had one cage cup with 30 bees, one with 60, one with 90, and one with 120. For the cage cups, I used 16 ounce plastic Solo® cups that were modified according to a protocol I wrote to look like figure 2. The cup with 30 bees received one 2-mL feeding tube of 1:1 sugar water, the cup with 60 bees received two, the cup with 90 bees received three, and the cup with 120 bees received four. Each day for seven days I would refill all of the feeders, count and remove any dead bees, and count and remove all the wax scales I saw in the removeable glass container underneath the cup. In order to get a better understanding of total wax production per cup, in addition to counting the wax scales produced each day, I would take note of any drawn comb I saw anywhere around the cup. I found that the bees in cups of 90 and 120, but especially the bees in the cup of 120, liked to build comb on the sugar water feeders, as seen in figure 3.
First Experiment
The first experiment I did this semester was focused on how having different numbers of bees in individual cage cups affects how many wax scales each bee produced on average, as well as how it affects any comb-building behavior within the cage cup. For my experimental setup, I had one cage cup with 30 bees, one with 60, one with 90, and one with 120. For the cage cups, I used 16 ounce plastic Solo® cups that were modified according to a protocol I wrote to look like figure 2. The cup with 30 bees received one 2-mL feeding tube of 1:1 sugar water, the cup with 60 bees received two, the cup with 90 bees received three, and the cup with 120 bees received four. Each day for seven days I would refill all of the feeders, count and remove any dead bees, and count and remove all the wax scales I saw in the removeable glass container underneath the cup. In order to get a better understanding of total wax production per cup, in addition to counting the wax scales produced each day, I would take note of any drawn comb I saw anywhere around the cup. I found that the bees in cups of 90 and 120, but especially the bees in the cup of 120, liked to build comb on the sugar water feeders, as seen in figure 3.
Figure 3 After the seven day period, I weighed all the wax scales from each cup to get an average weight per scale for each cup. From all of my raw data I was able to calculate a number of things, most importantly the average number of wax scales produced by each individual bee. This piece of information was the most important for my experiment because I wanted to show how population affected how much wax each individual bee produced. After analyzing my data, I found that the bees in the cup of 120 produced, on average, about 1.72 times more wax scales per individual bee than the bees in the cup of 30. This preliminary data seems to suggest that having more bees in a cup causes an increase in collective comb building behavior, as well as an increase in individual wax production.
Second Experiment
In my methods for the previous experiment, when quantifying the amount of wax produced, I only took into account the number of wax scales that fell through the bottom of the cup into the glass container. If my goal is to measure the total amount of wax produced in each cup, I need to find a method to quantify not only the wax scales, but the drawn wax as well. Once I have calculated the average weight of a single scale, I could simply weigh the pieces of drawn wax to get an estimate of how many individual wax scales were incorporated into building it. This data would be interesting because it would allow for a more complete measurement of the total wax produced per cup of bees, and it would also show the proportion of how many total wax scales produced were used for drawing wax.
Second Experiment
In my methods for the previous experiment, when quantifying the amount of wax produced, I only took into account the number of wax scales that fell through the bottom of the cup into the glass container. If my goal is to measure the total amount of wax produced in each cup, I need to find a method to quantify not only the wax scales, but the drawn wax as well. Once I have calculated the average weight of a single scale, I could simply weigh the pieces of drawn wax to get an estimate of how many individual wax scales were incorporated into building it. This data would be interesting because it would allow for a more complete measurement of the total wax produced per cup of bees, and it would also show the proportion of how many total wax scales produced were used for drawing wax.
Figure 4 However, it is not that easy to just weigh the pieces of drawn wax. Most of the drawn wax is on the feeding tubes, which are constantly being covered in sugar crystals and other detritus. This makes it unrealistic to simply weigh the feeding tubes with pieces of wax on them and trust the feeding tubes as stable weight references. Also, scraping the wax off of the feeding tubes to weigh is not a realistic option either because it would be nearly impossible to be certain that every last wax scale was scraped off. In order to solve this problem, a method must be devised to entice the bees to draw their wax in one area that can be easily removed and weighed without much threat of becoming overly dirty like the feeding tubes. In the second experiment I did over the semester, I attempted three different methods that aimed to serve as easily removeable and weighable spots for the bees to draw their wax.
Figure 5 My first method, as seen in figure 4, was a small circle of wax paper taped to the inside of the cloth mesh top. My second method, as seen in figure 5, was a small circle of wax paper the same size as before wrapped around an empty feeding tube, secured with a rubber band, and inserted through the cloth mesh top. My third method, as seen in figure 6, was a circle of wax foundation the same size as the wax paper attached with hot glue to a paper clip and suspended through the cloth mesh top.
Figure 6 This experiment, unfortunately, did not turn out how I hoped it might. The circle of wax paper with the tape and the piece of wax foundation both fell to the bottom of the cup after the first day, where they got absolutely covered in sugar water and other debris, along with getting chewed up by the bees. The feeding tube wrapped in wax paper stayed put the entire time, but there was no observable wax drawn onto it, and there was essentially no difference in its before and after weight. Any difference in weight could not be attributed to drawn wax. From this experiment, I learned that using wax paper and wax foundation are not good ideas because the bees like to eat them. They seem to really like building wax on plastic, so when I continue improving my methods for measuring the amount of wax scales used for comb building, I will be sure to incorporate plastic.
Conclusion
Since this was just my first semester working on this project, I still have a long way to go. I have learned a lot from my past couple experiments, and my current focus is going to be on finalizing the proper method for measuring the total amount of wax produced in a cup. My next couple experiments will be looking at how the incubator temperature in which the bees are kept, along with crowding, may affect wax production. After this, I will investigate how crowding along with feeding either honey or sugar water may have an impact on wax production. Throughout my next few experiments I will also be trying to find a threshold density of the number of bees per unit volume that seems to maximize wax production. I am very much looking forward to continuing my work on this project with the vanEngelsdorp Bee Lab!
References
Cassier, P., & Lensky, Y. (1995). Ultrastructure of the wax gland complex and secretion of
beeswax in the worker honey bee Apis mellifera L. Apidologie, 26, 17-17.
Goetze, G., & Bessling, B. K. (1959). Die wirkung verschiedener fütterung der honigbiene auf
wachserzeugung und bautätigkeit. Z Bienenforsch, 4, 202-209.
Hepburn, H. R., Bernard, R. T. F., Davidson, B. C., Muller, W. J., Lloyd, P., Kurstjens, S. P., &
Vincent, S. L. (1991). Synthesis and secretion of beeswax in honeybees. Apidologie,
22(1), 21-36.
Hepburn, H. R., Pirk, C. W., & Duangphakdee, O. (2014). Honeybee nests: composition,
structure, function. Berlin, Heidelberg: Springer-Verlag.
Pratt, S. (2004). Collective control of the timing and type of comb construction by honey bees
(Apis mellifera). Apidologie, 35(2), 193-205.
Winston, M. L. (1987). The biology of the honey bee. Harvard University Press.
Conclusion
Since this was just my first semester working on this project, I still have a long way to go. I have learned a lot from my past couple experiments, and my current focus is going to be on finalizing the proper method for measuring the total amount of wax produced in a cup. My next couple experiments will be looking at how the incubator temperature in which the bees are kept, along with crowding, may affect wax production. After this, I will investigate how crowding along with feeding either honey or sugar water may have an impact on wax production. Throughout my next few experiments I will also be trying to find a threshold density of the number of bees per unit volume that seems to maximize wax production. I am very much looking forward to continuing my work on this project with the vanEngelsdorp Bee Lab!
References
Cassier, P., & Lensky, Y. (1995). Ultrastructure of the wax gland complex and secretion of
beeswax in the worker honey bee Apis mellifera L. Apidologie, 26, 17-17.
Goetze, G., & Bessling, B. K. (1959). Die wirkung verschiedener fütterung der honigbiene auf
wachserzeugung und bautätigkeit. Z Bienenforsch, 4, 202-209.
Hepburn, H. R., Bernard, R. T. F., Davidson, B. C., Muller, W. J., Lloyd, P., Kurstjens, S. P., &
Vincent, S. L. (1991). Synthesis and secretion of beeswax in honeybees. Apidologie,
22(1), 21-36.
Hepburn, H. R., Pirk, C. W., & Duangphakdee, O. (2014). Honeybee nests: composition,
structure, function. Berlin, Heidelberg: Springer-Verlag.
Pratt, S. (2004). Collective control of the timing and type of comb construction by honey bees
(Apis mellifera). Apidologie, 35(2), 193-205.
Winston, M. L. (1987). The biology of the honey bee. Harvard University Press.
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