- Animals: bees
- Animal Production: livestock breeding, preventive practices
- Pest Management: genetic resistance, integrated pest management, traps
- Production Systems: holistic management
Drones: The Forgotten Bees. Exploring the use of drone comb traps to fight varroa mites and improve genetic diversity in open-mated queens.
Project leader, Ginger Davidson, was raised in rural Central Indiana not far from her family’s farm; a farm which recently received a Hoosier Homestead Award (an agricultural heritage honor given to farms owned by the same family for 100 years or more). After college, Ms. Davidson spent 20 years in the technology industry successfully managing multi-billion dollar projects for a variety of businesses. Then she returned to her rural farming roots. Owning over 115 acres, Ms. Davidson manages her farm’s major crop; fescue grass. Additionally, sheep, vegetable gardens, maple syrup evaporators, and bee hives dot the landscape. One thousand feet of Ohio River frontage provides a prime growing climate for 25 + acres of classified forest, an orchard with 90 fruit and nut trees, and a multitude of wildlife. In many ways a typical small acreage farm, it is unique in that it is also home to a federally and state approved grass runway airport known to pilots around the world. It is described as an ‘Aero, Agri, Eco Tourism Airport’ and was recently awarded an honorary distinction in tourism by the state’s Lt. Governor.
Beekeeping was added to the lifestyle in 2005 when an airport patron saw an interest and sent a ‘Beekeeping for Dummies’ book in the mail. With 2 beehives and no local mentor, the learning curve was intense. By reading, talking to other bee keepers, attending every meeting and seminar within a couple hundred miles, the apiary operation known as Geez Beez (named after its operator and a 1930’s racing plane) has expanded to 30 hives and draws patrons from all over the country who fly to the airport for honey. Additionally the river bottom, in which the apiary resides, is unique because it provides a micro-climate that brings Spring roughly two weeks ahead of the local area. This makes it a great location to raise bees and breed queens.
As for Ms. Davidson’s bee keeping background, she is a member of the Indiana Beekeeper’s Association (IBA), Indiana State Beekeeper’s Association (ISBA), and the Southern Indiana Beekeeper’s Association. She has participated in Purdue University’s Queen Rearing Short Course and now raises her own queens and sells queen cells. She was also recently selected by her local club to attend the Instrumental Insemination course taught by Purdue University. This course, developed with a grant from the Indiana State Department of Agriculture to the ISBA, was established as a means to create Indiana Queens. Additionally, she mentors two
14 year old students. One was administered through the Brent Bridwell Young Beekeeper Project via IBA.
The other is funded through her own accord. Due to her growing interest and participation in all things bees, she recently proposed and organized the first ‘Buzz About Bees’ education program for Clifty Falls State Park. It was a huge success and ended up as the largest event ever held at the park’s Nature Center.
Honey bee drones (males) are being ignored by bee keepers as they focus on mite control and queen rearing. In this project, ‘drone brood trap’ frames (DBT) will be removed from 'honey production hives’ (HPH) as a proven, non-chemical means to control mites during the spring and summer months. Instead of killing the drones like most methods suggest, capped drone frames will be moved into special ‘drone rearing colonies’ (DRC) so they can emerge as adults, saturate the local area, and potentially lead to better genetic diversity through open-mated queens.
1. Raise mature adult drones from DBT frames in DRC’s;
2. Compare DRC’s headed by mated queens versus caged, unmated (virgin) queens for sustainability;
3. Expand micro-breeder queen operation with open mated queens and drone saturation from DRC’s;
4. Utilize DBT’s to manage mite populations in HPH’s;
5. Increase honey production in HPH’s by removing DBT’s; and
6. Educate beekeepers on the importance and benefits of using DBT’s and DRC’s.
Varroa destructor mites emerged as a serious problem for beekeepers in the 1980’s. Now
roughly three decades later, they continue to threaten the survival of bee populations (managed and feral) as well as the pollination dependent crops. Mites induce stress for honey bees and are a vector for many diseases attributed to colony losses. Between 1948 and 2010, the number of producing colonies in the United States declined from 5.9 million bee hives to 2 million (USDA NASS).
Currently, all chemical miticide treatments negatively impact drone production. Initially the chemical approach was an application of moderately toxic pesticides; Apistan (fluvalinate) and Checkmite (coumaphos). Although very effective, issues surrounding their use compounded; mites developed resistance, chemical traces were found in wax, queen rearing was impacted, drones were not surviving, and those drones that did survive had reduced sperm production. Naturally occurring Thymol and Menthol also created post-treatment drawbacks with significant reductions in brood. Mite Away Quick Strips containing formic acid were recently approved and unlike other treatments can be used during honey production. Formic acid is the same naturally occurring chemical ants emit for defense. Unfortunately, colonies treated with formic acid remove drone eggs and delay production of new drones. Thus, although reported as safe, it results in half as many drones and occasionally a reduced worker brood population.
DBT’s on the other hand, are an effective non-chemical mite control method. Yet again, the drones are also destroyed. Research into the varroa mite’s reproductive cycle show female mites favor drone brood as a host for their eggs. While drones are in the capped stage of development, immature mites feed off of the drone pupae’s blood. Drones are favored because their cells remain capped an average of 2 days longer than a worker, and 6 days longer than queens. This gives the female mite, who lays singular eggs in 30 hour increments, an opportunity to lay more eggs thus increasing the mite population an average of 1 to 2 more mites per cell. With a potential of 8000 total cells on one frame of comb, 8000 to 16,000 more mites are possible in a frame of drone brood versus worker brood. Because of this biological anomaly, beekeepers have turned to natural control efforts that trap mites in drone comb. Such efforts typically involve this comb being frozen, scraped out, or shocked with electricity. Models supporting this method have predicted that reducing drone brood by 1% would reduce mite populations by as much as 25%. Once more, although very effective,
drones are sacrificed.
Some mite control methods have been implemented which do not impact drones; powered sugar dusting as a means to encourage bees to groom each other, screened bottom boards to keep fallen mites from returning to the colony, and local survivor queens genetically chosen for mite resistance are such examples. Among these, queen rearing through high-end breeders and local micro-breeders is the best natural, long-term option. This promotes bees that can deal with mites on their own accord. There is just one problem; how do we pass on all improved genetics?
Mite resistant, survivor queen programs can be found in each of the Northern States where genetic lines are being developed with both hygienic (cleaning out worker cells with mite infestations but not drone cells) and grooming behaviors (removing mites from the external surface of the bee). Oddly, with all this attention to genetics, little effort has been given to drones whose sole task is to pass on genetic material. This is easily evidenced by the amount of equipment found for sale in beekeeping catalogs for queens versus drones. Most beekeepers concentrate on keeping hives alive for honey production and perceive drones as resource consumers – they eat, mate, and die. However, efforts to control mites by killing drones or making them infertile goes against the genetic progression being made in mite-resistant bees. This oversight may very well result in more severe problems.
Unfortunately, solving this problem requires beekeepers to think differently
and change some longstanding methods.
Genetic diversity is very important to honey bees. It helps prevent infections, reduces the chance of non-viable drones being produced, and creates a hive of worker micro-colonies with diverse specialties based on the drone’s genetics. Yet for this to happen, a queen must be able to mate with drones from different colonies; the number of different drones mated with averages 13; the total sometimes reaching 26.
Drones are created when, under many varying conditions, the queen lays an unfertilized egg in a larger sized cell. Being haploid, they only bring one allele with them from their mother. If the drone’s mother (the queen) is a respected line, the male needs to be given the opportunity to mature, mate, and share his genetics (which is also the same as the queens) with other colonies as well. By killing drones or making them infertile, the potential for bees to naturally evolve to adapt to mites is also being lost.
Since mite infestations do not impact the drone’s mating competitiveness and more honey can be produced when drones are not in the hive consuming resources, DBT frames from HPH’s will be placed in separate colonies where drones can be raised to maturity and given the opportunity to mate. This will accomplish mite control and increase honey stores in HPH’s, while retaining adult drone populations. The drones chosen to be in the DRC’s will be from ‘selected’ genetic lines so that drone saturation will benefit open mated queens (feral and managed) and provide a drone bank for instrumental insemination choices.
We will start with 5 lines of bees in 20 hives – 4 hives of each line. Hives reared from the Indiana Queen (Purdue University grooming line) will be used for grafting queens (4 hives). The other 4 lines (16 hives) will be determined and installed with emphasis on hygienic behavior, honey production, over-wintering capabilities, and gentle temperament. The first year will be used to establish 16 HPH’s, draw out comb on plastic drone foundation, and become more familiar with DRC’s. The second year will allow us to compare two drone rearing methods and raise open mated queens with drone saturation from DRC’s.
Drones cannot feed themselves. Instead they rely on nurse bees (newly emerged worker bees) for that. This means that in addition to providing sugar water and pollen substitute, sufficient nurse bee populations are needed in hives intending to rear drones to maturity. In a hive headed by a mated queen, nurse bees are being created as long as the queen is laying eggs. Although this would be the preferable scenario for rearing drones, it is possible that nurse bees would see no purpose in having drones with a mated queen present and stop
feeding them. As a means of comparison, an unmated, caged queen creates the condition where nurse bees will think mating still needs to occur and therefore accept and rear the drones. However, nurse bees are not being created with this scenario. Thus for every 2 DBT frames being added to the DRC, a frame of emerging worker brood will be added from a brood donor colony. The two methods will be evaluated for empirical evidence of survivability.
Getting an accurate ratio of drones to nurse bees can be an area of concern for DRC’s. A feral colony will typically build 17% drone comb and have a 10% drone population. Each HPH will contain 2 frames of drawn out drone foundation installed initially into the hives at 2 weeks intervals resulting in 10% drone comb after the first 4 weeks. Each of the 4 DRC’s will contain 1 drone frame from each line of bees (4 drone frames = 20% drone comb). 2 DRC’s will be headed by mated queens and 2 headed by caged, virgin queens. A drone cell is capped in 10 days, ready to emerge approximately 2 weeks later, and mature enough to mate 2 weeks after that. Frames of mostly capped drone brood in the HPH will be exchanged every 2 weeks with frames in the DRC that have already emerged. The goal is to have drones emerging in the DRC and not the HPH. High mite counts are possible in DRC’s so powdered sugar dustings will be done in DRC’s only.
All hives will be maintained with standard beekeeping practices. Monthly mite counts will be made from April through September using sticky boards placed under screened bottom boards for 24 hours. Each mite will be carefully removed with small brushes and placed into an alcohol wash in a white dish where they can be easily counted. Then transferred onto a glass slide, they will be evaluated under a microscope for evidence of bee “grooming” indicated by missing parts. Monthly records will be maintained on both of these counts as well as hive population estimates, honey production, drone frame exchanges, number of capped drone cells on exchanged frames, amount of food (sugar water/honey and pollen) provided to DRC’s, and winter losses.
Mar 2013 Receive notice of grant funding from SARE
Apr 2013 Locate and determine genetic lines, order equipment, set-up a minimum of 16 HPH’s, and start drawing out plastic drone foundation
Summer 2013 Prepare DRC equipment
Mar 2014 Evaluate status of over-wintered hives
(expect 15 – 20% loss as a favorable condition as we are looking for survivor stock)
Apr 1, 2014 Install 1st frame of drawn out drone foundation in all HPH’s
Apr 15, 2014 Install 2nd frame of drawn out drone foundation in all HPH’s
Apr 30, 2014 Progress report due
May 1, 2014 Set up DRC’s; 1st move of frames into DRC’s
May 15 – Sept 2014 Exchange DRC and HPH drone frames on biweekly schedule; begin raising queens
Oct – Dec 2014 Finalize reports; create outreach video
Jan – Mar 2015 Attend meetings; write & submit articles; share video link with social media sites
Apr 2015 Count mites – including new hives from queens created previous year with DRC’s
Apr 30, 2015 Final report
Previous SARE funding has been used to raise mite-resistant bees, to make these bees generally available to beekeepers through Indiana Queens (and similar projects in neighboring states), to create and disseminate nucs of bees bred from Indiana Queens to beekeepers in the state, to teach beekeepers how to raise queens, and how to artificially inseminate queens. Having participated in all these projects, the project leader feels one very important aspect has been overlooked; DRONES; THE FORGOTTEN BEE. Although SARE has funded projects which used drone brood trapping for mite control and pesticide reduction, this project will greatly expand on those efforts by rescuing drones for improved genetic diversity.
Develop informational YOU TUBE video describing the project, problems, solutions,
methods, and results with photos and video taken throughout the project. List link to video in an article submitted to both state beekeeper associations for inclusion in newsletters (1000+ beekeepers). Share video link on beekeeping FACEBOOK pages (state, local, and national). Share information at local club meetings (over 75 members) and publish information with links to video on club’s website (1000’s of hits monthly).
A database will be kept and reviewed for impacts on mites and grooming behaviors in
HPH’s, DRC’s, and new open mated queens. If a viable, easy method for sustaining DRC’s can be found, it may greatly change the way beekeepers operate and potentially result in bees being able to evolve and pass on traits needed to survive without beekeeper intervention. Overall, hives that produce more honey with fewer chemicals provide an economic reward for beekeepers and a better product for consumers. Increasing genetic
diversity with drone saturation benefits the species resulting in ongoing pollination and better food for the world. All in all, it provides a positive influence toward improving the sustainability of honey bees in Indiana.