Source: CORNELL UNIVERSITY submitted to
SUSTAINABLE SOLUTIONS TO PROBLEMS AFFECTING BEE HEALTH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0223284
Grant No.
(N/A)
Project No.
NYC-191833
Proposal No.
(N/A)
Multistate No.
NC-_OLD1173
Program Code
(N/A)
Project Start Date
Oct 1, 2010
Project End Date
Sep 30, 2013
Grant Year
(N/A)
Project Director
Seeley, TH.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
Neurobiology & Behavior
Non Technical Summary
The mite Varroa destructor poses a large threat worldwide to honeybees. If a colony of bees does not receive mite control treatments, the population of mites in it will grow rapidly and will kill the colony. The problem of Varroa is probably exacerbated by how beekeepers manage their colonies. Beekeepers crowd numerous colonies into apiaries, which facilitates the drifting of mite-infected workers between colonies, and they transfer combs of bees between colonies in an apiary, which further facilitates the spread of the mites. Thus, beekeeping practices promote the horizontal transmission (i.e. the infectious transfer among unrelated hosts) of mites between colonies. This makes it easy for virulent strains of the mite to infect all the colonies in an apiary. Moreover, over time, these practices promote the evolution of ever-more virulent strains of the mite by favoring those that strongly reproduce in one colony and then spread to other colonies. One might expect, however, that if beekeepers kept their bees in a way that hinders rather than fosters the horizontal transmission of mites between colonies, then in the short term beekeepers would limit virulent strains of Varroa mites to fewer colonies and over the long term beekeepers would favor the evolution of avirulent strains of mites. The proposed work will evaluate the effectiveness of a method of beekeeping that hinders the horizontal transmission of mites among colonies. If it proves effective, it will provide beekeepers with a means of achieving sustainable beekeeping without the use of miticides.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31230101110100%
Knowledge Area
312 - External Parasites and Pests of Animals;

Subject Of Investigation
3010 - Honey bees;

Field Of Science
1110 - Parasitology;
Goals / Objectives
To develop and recommend to beekeepers "best practices" for varroa mite control based on currently available methods and strategies for mite management. To evaluate the role and causitive mechanisms of parasitic mites and pathogens such as viruses, protozoa and bacteria in honey bee colony deaths. To determine the effects of pesticides and other environmental chemicals on honey bee colony health. To determine how environmental factors, including nutrition and management practices affect honey bee colony health. To determine the effects of interactions among various factors affecting honey bee colony health. To coordinate research and extension efforts related to bee colony health.</li> To facilitate, through research and extension activities, the development of industry-based honey bee stock selection, maintenance and production programs that demonstrably incorporate traits that confer resistance to pests, parasites and pathogens. To focus on non-Apis bees, their conservation, pathology, susceptibility to pesticides, and their contribution to crop pollination including economic value.
Project Methods
In year 1, I will set up two groups of 15 colonies. In one group (the Apiary Group), the colonies will be clustered in an apiary. In the other group (the Dispersed Group), the colonies will be dispersed. The two groups will live in the same area. They will be started using 15 pairs of artificial swarms prepared from 15 colonies that are infected with Varroa. The swarms will be headed by sister queens. Because both swarms in a pair will come from the same colony, they will have similar levels of mites. Each swarm will be installed in a 10-frame hive on combs without drone cells, to equalize opportunities for mite reproduction. Twice each summer, I will simulate the comb exchanges that beekeepers perform ; each colony in the Apiary Group will give to and receive from another colony two combs of bees. There will be no comb exchanges between the colonies in the Dispersed Group. All colonies will be managed for honey production. Once a month, I will examine each colony and will measure its size (frames of bees and brood) and its mite level (number of mites trapped on a sticky board in 48 h and number of mites on 300 worker bees). In the fall, I will measure each colony's honey production. Using a paired-comparisons statistics, I will test for differences between the two treatments in bee and brood population, mite infestation, and honey production. In year 2, I will continue the monthly measurements in the two groups of colonies. In years 3 and 4, I will repeat the entire experiment in a different location and with two new groups of colonies.

Progress 10/01/10 to 09/30/13

Outputs
Target Audience: My target audience has been small-scale and hobby beekeepers. I reach them through articles published in various beekeeping magazines (e.g. Bee Culture) and through talks given to meetings of beekeepers associations (e.g. the annual meeting of the Eastern Apicultural Society). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? It provided training in beekeeping and in research for one Cornell undergraduate student in each summer. Summer 2011: Sean Griffin Summer 2012: Carter Loftus Summer 2013: Maddie Ostwald How have the results been disseminated to communities of interest? I am currently writing the manuscript that will be the formal, scientific report of the findings. The title of this paper is "A major transition in honey humans exploit honey bees has strongly affected their disease ecology." Once I have this paper published, then I will write a report for beekeepers to be published in Bee Culture. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Over the summers of 2011, 2012, and 2013, I completed the proposed experiment. I hypothesized that the damage suffered by honey bee colonies from Varroa mites will be greater when they are crowded rather than dispersed. In particular, I hypothesized that a population explosion of mites in one colony will tend to spread among crowded colonies but not dispersed ones. To test this hypothesis, I (1) established two groups of 12 colonies, one with the hives crowded (spaced 1 m apart) and the other with the hives dispersed (30-80 m apart), (2) measured the levels of bee drift between the colonies, (3) tracked the dynamics of the Varroa mite populations in the colonies, and (4) recorded the pattern of colony mortality for the two groups. I found stark differences between the colonies in the crowded and dispersed groups. With respect to bee drift, I found that in the crowded colonies, only 52-58% of the bees entering a hive were bees reared in the hive, hence there was tremendous drifting of bees between the crowded hives. In contrast, I found that in the dispersed colonies, 99-100% of the bees entering a hive were bees reared in the hive, hence there was negligible drifting of bees between the dispersed hives. With respect to Varroa dynamics, I found that in the group of crowded colonies, colonies that had relatively few mites all summer long suddenly showed surges in their mite populations in late summer when nearby a colony (or colonies) collapsed from a population explosion of mites in it (them). But in the dispersed colonies, I found that colonies that had relatively few mites all summer long DID NOT suddenly show surges in their mite populations in late summer when a nearby colony colllapsed from a population explosion of mites in it. With respect to colony mortality, I found that 0 out of 12 colonies in the crowded group were alive after 2 years, but that 5 out of 12 colonies in the dispersed group were still alive after 2 years (a highly signficant difference: P = 0.035). (Note: none of the colonies were treated with pesticides to control the mites.) The results of this project reveal that crowding colonies in apiaries, which makes beekeeping practical, is not altogether beneficial for the bees, because it increases the risk of acquiring infections of pathogens and parasites from neighboring colonies. Small-scale beekeepers and hobbyists will benefit greatly from arranging their hives in a dispersed rather than a crowded layout.

Publications

  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Seeley, T.D. 2012. Using bait hives. Bee Culture (April) 73-75.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Seeley, T.D. 2012. Capturing swarms with bait hives. The Beekeepers Quarterly (March) 33-35.
  • Type: Journal Articles Status: Submitted Year Published: 2014 Citation: Seeley, T.D. and M.L. Smith. A major transition in how humans exploit honey bees has strong affected their disease ecology. Apidologie
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Seeley, T.D. Honey bees in the wild. Presentation at the Eastern Apicultural Society Annual Conference, Philadelphia, PA 5-9 Aug 2013
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Seeley, T.D. Honey bees in the wild. Pacific Northwest Treatment-Free Beekeeping Conference, Portland, OR, 26-29 July 2013
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Seeley, T.D. Honey bees in the wild. Presentation at the University of Georgia Beekeeping Institute, Young Harris, GA, 10-11 May 2013
  • Type: Journal Articles Status: Submitted Year Published: 2014 Citation: Seeley, T.D., D.R. Tarpy, S.R. Griffin, A. Carcione & D.A. Delaney. A survivor population of wild honeybee colonies living in eastern North America. Submitted to The Proceedings of the Royal Society of London B.


Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: I have given five talks to beekeeper associations on the theme of "Honey Bees in the Wild." These talks have featured the preliminary results from my research on colony spacing. I'm happy to report that there is great interest in this work! North Carolina Beekeepers Association, 15 Oct 2011 Marin County (California) Beekeepers Association, 6 Jan 2012 Geneva (New York) Bee Conference, 24 Mar 2012 Eastern Apicultural Society (Annual meeting, in Vermont), 8 Aug 2012 Western New York Honey Producers Association, 8 Sept 2012 PARTICIPANTS: Thomas D. Seeley, professor, Department of Entomology Cornell University. designed and led the investigation. Jon Carter Loftus, undergraduate student, College of Agriculture and Life Sciences, Cornell University. Research assistant on the investigation. This introduced him to methods of data collection, data analysis, and beekeeping. Jon Ryan, commercial beekeeper, Genoa, NY. Partnered with PD in maintaining the honey bee colonies needed for this investigation. TARGET AUDIENCES: Beekeepers worldwide, but especially in North America and Europe. The research project is the first step in a series of investigations that is examining how colonies of honey bees living in the wild, and so not being given treatments for the control of Varroa mites and their associated viruses, are able to persist. PROJECT MODIFICATIONS: No major changes.

Impacts
As I write this (13 Dec 2012), the two groups of study colonies (crowded and dispersed) have passed through their second summer, and they have showed me several things of interest. 1) I found a large difference between the two groups in the level of drifting of drones between hives. The percentages of drones in each hive that were from another hive were as follows for the two types of hives: crowded hives: 42.1%; dispersed hives: 0.2%. It is clear that the colony spacing treatment strong affects the amount of drift of bees (drones, at least) between hives. 2) I found that the populations of Varroa mites increased to much higher levels in the colonies this (the colonies' second) summer relative to last summer. More importantly, I found that the Varroa populations were consistently lower in the dispersed colonies than in the crowded colonies (in late July, the mite drop counts in 48 hours [X,SD]: 75,69 vs. 245,139, P less than 0.01. I now need to see whether this difference results in a difference in colony survivorship between the two groups. 3) In both treatment groups, 7 out of 11 colonies swarmed, and I found a huge difference in mite loads between colonies that did and did not swarm. Mites/100 adult bees: swarming colonies, 0.9, 0.4: non-swarming colonies, 6.2, 2.9, P less than 0.04. This difference was detected in late July, hence at the end of the swarming season. Interestingly, this difference between swarming and non-swarming colonies persisted into September in the dispersed colonies but not in the crowded colonies, probably because of mixing of bees and mites among colonies in the crowded group. Fascinating! It will be interesting to see how this effect of swarming on mite loads affects colony survivorship. I'm very much looking forward to following these colonies through the winter of 2012-2013. There are 8 colonies still alive in both the crowded and dispersed groups. This study is progressing nicely toward providing the beekeeping community with solid information on whether or not increasing the spacing of hives improves colony health by reducing the horizontal transmission of parasites and pathogens between colonies. The final conclusions on the outcome of the study will come in the spring or summer of 2013, when I see how the health of the remaining colonies looks after the winter of 2012-13. If I find a marked difference in colony health between the two groups, this could cause beekeepers to rethink their standard practice of keeping hives crowded together in apiaries, which is actually a very unnatural living situation for honey bees.

Publications

  • None yet. I will publish the report on this study in 2013, once I know the full outcomes of this multi-year experiment.


Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: The principal output over the first year of this project (2010-2011) has been an Activity: establishing the two groups of genetically homogeneous colonies that are infested with the mite Varroa destructor (and associated viruses). The two groups were managed in ways that either foster or hinder the transmission of mites among the colonies within a group. To foster mite transmission among colonies within one group, I set up the colonies close together (in an apiary, as is usual) and I moved combs with bees and brood among the colonies once a month (as is common). To hinder mite transmission among colonies in the other group, I spaced the colonies widely and I did not move combs between them. The set up of the two groups was accomplished in June 2011. I then monitored the colonies, through the middle of October, in terms of mite load, colony growth, weight gain, and survival. I will continue monitoring these colonies for at least another year (to October 2012, if not beyond). This will reveal whether reducing the horizontal transmission of Varroa mites among honey bee colonies is helpful for achieving sustainable beekeeping without the use of miticides. PARTICIPANTS: Thomas D. Seeley, Principal Investigator Sean R. Griffen, Undergraduate Assistant TARGET AUDIENCES: In 2011, the PI described his research on sustainable beekeeping to various groups of beekeepers, including the New York City Beekeeping Group, the Long Island Bee Club, the Worcester County [Massachusetts] Beekeepers Meeting, the Rhode Island Beekeepers Association, the Swedish Beekeepers Association, the Champlain Valley [New York and Vermont] Beekeepers Association, the Greater Cleveland Beekeepers Club, the Empire State Honey Producers Association, the York County [Pennsylvania] Beekeepers Association, and the Denver Bee Club. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The principal outcome over the past year has been a Change in Knowledge. Specifically, I have already learned that there is a huge difference between the two treatment groups (crowded colonies vs. dispersed colonies) in the level of "drifting" of drones between colonies. Within each group of study colonies, I placed two drone-source colonies that were producing drones phenotypically distinct from those from the study colonies. Then I monitored the study colonies during times of drone flight to see whether any of the phenotypically distinct drones had moved into the study colonies. The result was crystal clear: all of the study colonies that were crowded together, but none of the study colonies that were dispersed, had acquired a large number of foreign drones. Thus, it is clear that the colonies in the two treatments (crowded vs. dispersed colonies) have markedly different levels of drone drift, and thus of horizontal transmission of Varroa mites. Great! Now, I just need to see what the consequences of this difference are on colony health.

Publications

  • No publications reported this period