By Ginger Davidson
Recently, I was selected and funded for a small research grant project to look at using drone frame trapping to control mites while raising those drones to maturity for mating purposes. Why in the world would you want to do this? Through a serious of small articles, you can follow my logic as we look at the importance of drones and why I think they are often overlooked and forgotten in the grand scheme of the bee world.
It is my belief that there is not just one but several stress factors impacting bees: nutrition, pesticides, genetics, mites, and disease. Most of these factors are not only inter-related but human created, controlled, and fixable if we choose to find a balance point to do so; except mites. The spread of mites could be attributed to humans but we are probably not going to be able to eradicate them. For a long term solution, humans might be able to help the bees speed up the process of dealing with them and that is where we start. So, let’s look at mites as they relate to this project.
When a mite bites a bee, they make a wound that is relatively speaking the size of an open sore on the back of a beekeepers hand. Can you imagine having a sore on the back of your hand, going into a restaurant where the waitress that serves you food has a similar lesion and has been in contact for the past month with others that have the same type of sores? We would demand health officials to take action and terminate this unsafe practice. This type of comparison, although rather disgusting to think about makes it easy to see how the bee’s social lifestyle spreads disease quickly within a hive. So when they say the mite is a vector for disease, it all starts to make sense.
Looking at the life cycle and reproductive cycle of a mite, helps to further understand why mites are such a threat and problem to our honey bees. The small, blind female mite uses odor to invade a cell 0-18 hours prior to it being capped. She lays singular eggs in 30 hour increments under capped brood cells where the mites feed off of the blood of the growing bee pupae. Since a drone cell is capped an average of 2 days longer than a worker, the drone cells are therefore preferred by mites and can contain an average of 1 to 2 more mite daughter eggs per cell as compared to worker brood. With approximately 7,000 to 8,000 cells on both sides of a deep frame, this means that a complete frame of drone brood has the potential to produce 16,000 more mites than a frame of worker brood. A feral colony of bees will build about 17% drone comb which equates to 3.4 frames in a standard, Langstroth, 10 frame, double deep hive. Therefore, theoretically speaking, there is the potential for 54,400 more mites in drone brood. That is just the above and beyond number and we haven't even addressed the potential for worker brood. Wow! We all know that every hive performs differently and none according to ‘the book’ but it quickly illustrates how a colony of 50,000 bees can become infected with mites.
Knowing about the mite’s inclination toward drone brood, led to the creation of a non-chemical method of mite control called drone frame trapping. Research at Dyce Laboratory for Honey Bee Studies at Cornell University (and other studies as well) has shown that the periodic removal of drone brood from a colony allows a beekeeper to skip the usual spring treatment, keep mite levels low throughout the summer and prevent fall collapse. Pierco makes green plastic drone frames and some beekeepers allow bees to make their own drone cells. Meticulous maintenance practices are required to remove the capped drone frames before they start emerging otherwise you will be raising mites instead of bees. Typically, the frames are scraped off, frozen or fed to the chickens and there are even devices to electrocute the brood in the frames. All of these effectively remove the mites in the drone cells but also kill the drones before they reach maturity.
By killing so many drones, I have to wonder if we are losing our ability for the bees to adapt on their own to mites. This is one of the many facets leading to this project. Can I minimize mite infestation from my production hives using drone frame traps yet keep the drones alive in a drone rearing hive?