It Takes a Colony: Raising Varroa in the Lab

Photo: Cameron Jack, Lecturer and Distance Education Coordinator at the University of Florida

Cameron Jack Grew up watching his grandfather work 150 hives in southern Nevada.   This was his gateway-bee experience.  Learning and watching – being taught about honey bees.  Today, Cameron is a researcher and lecturer at the University of Florida, Department of Entomology and Nematology. 

Cameron received a one-year Costco/PAm fellowship award in 2016 to conduct research at the University of Florida where he is completing his graduate work.  The subject of his research:  Varroa.  More specifically, his focus has been on breeding Varroa in vitro in the laboratory.  

Varroa control has been at the forefront of honey bee research since the mites arrived in the US in the late 1980s.  In the late 80s and early 90s, researchers recognized the benefit of having a supply of varroa mites on hand in order to conduct research about how to combat their detrimental effects. Despite many efforts, this research was abandoned due to a lack of successful outcomes, but ask any Varroa researcher, and they will tell you a major challenge it is to amass enough of these parasites for their studies, without losing the colonies that harbor them to dwindle and demise.
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Most agricultural insect pests can be cultured and bred in the laboratory, allowing scientists to access a steady supply of “test subjects” which help them develop control tools and study the insects.  But Varroa are so intrinsically linked to honey bees that when you remove the live bee colony, it is very difficult to get varroa mites to reproduce.  Currently, researchers can only get Varroa to reproduce in vitro when they have access to a live bee pupa in a capped cell.  This means that in order to have access to Varroa for research purposes currently, they must be harvested out of a honey bee colony. 

This can be problematic and often researchers are challenged with keeping a colony with high mite infestations, harvesting mites from these colonies, and trying their best to not let a research hive die at the same time.  It’s challenging, and more so in areas that experience winters where mites cannot be harvested for 6-7 months out of the year.  The process of harvesting mites for research is painstaking and costs a colony many bees, or frames of brood – not to mention that these colonies have high mite infestation levels putting additional stress on them. ​

Photo: The gel capsules method involved collecting worker bee larvae and adult Varroa females from cells that had been capped recently and placing them into gel capsules 6 mm in diameter with small holes added for ventilation.

Despite a historic lack of success by researchers, Cameron Jack is inspired by the great value in developing these tools, and is working to improve old ideas and explore new ways to rear Varroa in the lab. He describes his work as being focused not only on what might work, and what is worth developing, but also eliminating methods that do not work.  What he found is that the most promising methods include rearing Varroa on bee pupa in gelatin capsules which mimic brood cells.  Using this method also allows scientists to visually observe what is going on in the capsule.  He recounts what doesn’t work well includes putting bee pupa in a petri dish with Varroa mites, or raising Varroa in a bee larva which has been grafted into cell culture plates. 

Figure. An open gelatin capsule with immature female and male Varroa on a honey bee pupa.

Cameron has also looked at artificial diets which do not require live honey bees, but provide Varroa with what they need to reproduce successfully.  This preliminary research has helped him and his graduate advisor, Dr. Jamie Ellis, acquire post-doctoral funding to continue the research inquiry and develop artificial diets for Varroa further.  Cameron is hopeful for the future and says “We are making more progress than has been accomplished ever before.”

And to his point:  Cameron’s research is not happening in a vacuum.  He says: “A lot of people have come together in the past year or so to put their heads together.  There are USDA scientists in Beltstville, MD working on this with Dr. Steve Cook.  At The University of Maryland VanEnglesdorp lab, a student has been working partly on observing Varroa feeding, and also trying to observe reproduction in the lab.  And there are people in the industry involved – for example, Monsanto researchers are also trying to improve Varroa rearing. All of us have come together and have been working collectively in these projects trying to advance and accomplish the goal of rearing Varroa in vitro.”  Each of these pieces helps point towards solutions.

Photo: A foundress Varroa and her fully mature daughter reared in a gelatin capsule in vitro.

Having access to a better supply of Varroa would clearly be a step forward with any efforts to combat this deadly mite.  But what do “solutions” mean for beekeepers?  One example of how this technology could help immediately is related to Varroa’s ability to quickly develop resistance to chemical treatments.  In the past, when a treatment has become available it is typically widely and frequently used by beekeepers which can accelerate resistance in mites.  If researchers had more varroa mites to work with in the lab, throughputs could increase, and new treatment options could be produced faster, potentially allowing a greater diversity of effective treatments to be available.  Rotation of a larger variety of treatment products helps reduce the speed at which Varroa develop resistance.

While Cameron’s research is clearly valuable, he says that teaching was his first love and it still plays a big role in what he does.   Recently, Cameron was hired as a lecturer in the Department of Entomology at the University of Florida.  He also teaches beekeeping classes, and is developing beekeeping courses with the goal of helping more beekeepers be successful and learn the scientific background of  many management practices.  But perhaps the teaching project he is most excited about is developing a course for undergrads of all backgrounds based on honey bee research, where students will be doing real, publishable research.

Cameron says that for him, teaching and research is all tied together.  “Exposing students of all backgrounds to research, and to honey bee research in general is the goal.  Getting more new and brilliant minds into the field is going to be really important for the future. I can be a lecturer and still do research – that's how you learn more.  It’s all connected.”

I asked Cameron if he had developed any sense of empathy or fondness for the unique and specialized Varroa mite during the process of breeding them in the lab.  He told me that "The way the Asian honey bee and Varroa have evolved together is very interesting...  Their biology is fascinating; but I still take great pleasure in killing them.”

Research like this takes time and is one example of how some of the research we support today is an investment in the future.  Sometimes we find quick, easy solutions to honey bee health threats, and that is important – but we also need to be looking at the long-term, bigger picture of the future of research tools, honey bees and agriculture.   

​Cameron Jack is a Ph.D. candidate and was recently hired as a Lecturer and Distance Education Coordinator at the Entomology and Nematology Department at the University of Florida. His goal is to create an educational program that prepares students for the many challenges associated with beekeeping and to train those interested in entering the beekeeping workforce. His main interest is to serve the beekeeping industry by providing practical solutions to beekeepers seeking to improve honey bee health. Currently, his research efforts are focused on honey bee epidemiology and toxicology.

Click Here for a list of Cameron's research publications

By Sharah Yaddaw
Communications Director,
Project Apis m.