Observations pertaining to Colony Collapse Disorder
As someone that has had a hand in bee keeping for the past forty years I wanted to share my observations on CCD and my hypothesis for causality. Currently I am living on the island of Bermuda and find it provides a unique opportunity to observe the evolution of CCD. Bermuda is small and isolated and is currently a closed eco system where honeybees are concerned (total restriction to any importation of honeybees). Unfortunately, the ban on importing honeybees into the island was put into effect after 2006, so CCD was inadvertently introduced to the island’s honeybee population. The result was a loss of up to 50% of the honeybee colonies on the island. CCD continued to have a devastating effect on the honeybee population until 2014. Since then, honeybee population has risen sharply.
As noted by a number of research groups investigating CCD, there are no absolute common factors shared by all cases of CCD. The fact that a hive appears healthy one week and has gone into collapse the next almost suggests an external variable that is not yet known to us. The fact that the onset of CCD can take place at any time during a given queen bee’s lifecycle suggests that the disorder is not the result of genetic defect but rather external causality. I would like to challenge this assumption.
As I mentioned, I am currently living in Bermuda where many of the chemicals/pesticides used in the agriculture industry in the USA and Canada are not used. And certainly, there are areas in the US, Canada and the world at large where chemical usage varies from region to region. (This is not to say that we should ignore this issue. The world’s eco system cannot sustain this type of abuse indefinitely. Opposition to many fertilizers, pesticides and chemicals must be maintained.) However, as there is no absolute commonality regarding chemical causality, there are only two other possibilities: a bio pathogen/disease or genetic disorder.
My observations lead me to consider the latter (genetic disorder) as being the most viable. This next observation is common among long term bee keepers but I feel is critical to the subject of CCD. Bee colonies can have varying temperaments and these can change from month to month or even week to week. One week I go to check on a hive and it has a very mild temperament and two weeks later I go to the same hive and the bees are much more aggressive. This phenomenon also works in reverse and with no commonality to time of the season. Why?
Drones are the logical reason. When the queen mates she takes in genetic material from a number of drones. These drones can come from numerous hives with varying temperaments. After mating with a new queen, their genetic material is stored in the spermatheca. The sperm is stored in layers and used in succession; it is not a mixed slurry of genetic material but is relatively waxy and dry and segmented into distinct layers.
So, as the queen runs out of one drone’s genetic material she begins to use that of another drone. This would explain the sudden change in temperament: the first batch of sperm coming from a drone born of a colony with a mild disposition and the second from a drone with a more aggressive temperament. In my observation of CCD, the time frame for this change is similar (approximately two weeks). (During the first week, it is hard to recognize any change as there are still thousands of bees in the hive and activity is visible. The second week brings the sudden and obvious depletion of worker bees in the hive.)
It is also important to note that during CCD, the bees are leaving the hive as if it’s business as usual. They do not suddenly swarm out of the hive and are gone. They leave the hive to forage and simply do not return. This continues to occur for a few weeks until the hive is depleted of workers. Remember, bees only live a few weeks during the honey flow so it would take only a week or two to critically cripple the hive and three to four weeks to render it without any workers. Only the youngest of bees would remain to work with the brood and queen, as is their nature. There is only one rational reason for the worker bees not returning. They got lost. A piece of genetic information (genetic memory) is missing or has been damaged. They act like normal bees and go out foraging but are unable to find their way back. This is not to say that genetic memory is the only symptom of the genetic disorder but it is the most obvious.
I would hypothesize that the CCD phenomenon is being spread through the drones and does not become evident or have effect until there is a succession or transition of genetic material being used within the queen to fertilize eggs.
I would also hypothesize (through logical deduction) that the defect is recessive within the queen but dominant within the drone. This makes sense because the drone only gets its DNA from the queen and only gets one set of chromosomes (13). If she happens to pass on this recessive CCD gene it then become dominant in the drone as there is no other DNA to keep it in its recessive order.
As the drone DNA is used to determine the sex of the bee and if the drone has been given this recessive CCD gene from its queen, all eggs fertilized with this drone’s DNA will produce worker bees with this recessive DNA, as it is the only DNA available in their development. (We would also have to assume the genetic memory for navigation is passed to the worker bees from the drone DNA and not the queen’s DNA.) Again, it would only become evident that this CCD DNA is present after the queen has used up the sperm of one of her other mates and begins using the DNA of the defective drone. She would lay up to 1,500 eggs a day and as the older bees died out the younger CCD worker bees would fill the hive until they matured and it was time for them to go out and forage. This would deplete the hive of worker bees rapidly (ten to fourteen days). It would also explain the hive being left full of stores, brood and the younger worker bees. It would only take a day or two for this hive to be discovered by other bees and robbed to the point of collapse.
I understand that there has been a sharp decline in the number of colonies lost to CCD in Australia and New Zealand. The fact that the varroa mite is absent from their honeybee populations should not bear great significance as Bermuda does have the varroa mite but has also seen the same reduction in losses due to CCD.
There have been a number of beekeepers that have reported the occurrence of CCD to be greater in some areas than in others. The hypothesis that defective drone DNA is the cause of CCD also fits this phenomenon. Drones rarely deviate from the Drone Congregation area that is closest to their colony. Therefore, CCD drones will only affect a localized area. Swarms will tend to travel a little farther afield, causing their drones to interact with new Drone Congregation areas but not to the extent that beekeepers have when they transport hives greater distances for crop pollination.
So what can be done to stop this?
If the above hypothesis is correct, then we do know a few useful things that might help produce a solution.
1. If the queen has the recessive gene, it is only transferred 50% of the time and only when producing drones.
2. Any colony that falls victim to CCD dies out quickly. This limits the number of defective drones that are available to mate.
This means there is limited opportunity to spread the defective DNA.
It is also possible that any queen genetics that are resistant to the CCD DNA will survive.
3. In larger, uncontrolled areas such as the USA and Canada, I believe this genetic flaw will need to be resolved through breeding programs that will produce new healthy DNA within the queen bees. One very positive observation is what is happening with CCD here in Bermuda. As mentioned, Bermuda has a closed, controlled eco system. The occurrence of CCD has dropped off to insignificant numbers. Where the island lost 40% to 50% of its colonies during the 2006 to 2014 period, there has been a significant increase in numbers of honeybee colonies and only slight losses due to CCD between 2014 and 2017. This indicates a correction within nature to overcome the genetic disorder. These statistics do not take into account colony losses due to other causes: disease, mites, poor breeding, wax moth, exposure to pesticides/chemicals and any combination of the aforementioned.
I have put together a chart to map the CCD DNA transfer from queen to drone to worker bee. Feel free to contact me if you are interested or if you wish clarification on any of the above.
I hope you have found these observations informative. As I mentioned, the solution to this issue is beyond me but I hope my hypothesis of the problem will help others find solutions.
All observations written in this thread should be considered ‘Open Source’ and free for anyone to use.
Thank you for taking the time to review the above.