Evaluating two-colony hives for increased productivity and varroa mite control

Final Report for ONE05-034

Project Type: Partnership
Funds awarded in 2005: $9,744.00
Projected End Date: 12/31/2007
Region: Northeast
State: Pennsylvania
Project Leader:
Maryann Frazier
Penn State University
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Project Information

Summary:

Note to the reader: graphs and figures referenced in the text can be requested from Northeast SARE. Send e-mail to nesare@uvm.edu and request final report materials for ONE05-034.

Beekeeping in the Northeast United States and in other northern climates is, at present, only a marginally sustainable form of agriculture. Using a prior SARE Farmer Grant, Mike Johnston has designed and conducted preliminary testing of a two-colony hive that has shown promise of improved overwintering, honey production and possibly nucleus colony (aka nucs – units used for starting new colonies or replacing dead colonies in spring) production.

We tested this hive system in three locations in the Northeast and compared this hive type against the standard Langstroth hive for improved overwintering, survival, honey production and bee (nuc) production. The results from the three different locations yielded dramatically different results.

In general, the two-colony hives did not outperform the standard hives in this limited one-year test. From previous studies and reports, including work conducted by Mike Johnston, the two-colony system may be more productive when, in spring, the overwintered clusters are used to repopulate standard hives and then they themselves are restarted headed by new queens. Earlier studies found that under these circumstances the two-colony hives could produce more bees and even more honey. But the two-colony hives were not more profitable than standard hives when they were overwintered and maintained as production colonies in the manner used in this experiment.

Project Objectives:

The overall objective of this project was to compare the performance of two-colony hives against traditional ten-frame hives.

The following were used to evaluate the two different hives types over a period of a year and a half:

• Varroa mite levels*

• Honey production

• Overwintering survival

• ability to produce bee (nucs)

*During the course of the project we did decide to treat the colonies with formic acid to control varroa mites. We concluded that this was an additional variable that could interfere with our ability to evaluate the production performance of these two systems. Mike Johnston opted not to treat his colonies.

Cooperators

Click linked name(s) to expand
  • Craig Cella
  • Mike Johnson
  • Robert McMillin

Research

Materials and methods:

On June 20, 2005, 20 two-colony hives with bees and 20 five-frame nucleus colonies with bees were purchased from Mike Johnston and brought to Penn State University. Ten of each were placed on hive stands in the Wiley University Apiary. The bees and frames from the ten nucs were transferred to standard hives and located together in the lower half of the apiary, the ten two-colony hives were placed together in the upper half of the apiary. The two areas are separated by a tree line.

On June 23, 2005 Bob McMillian picked up his ten two-colony hives and ten nucleus colonies. They were transported to his home in western PA where he placed in one apiary but divided into the two groups by hive type. Mike Johnston also set up an apiary at his home location with ten of each of the two hive types for comparison. The apiaries were established in the following locations:

Morrisville, NY;

State College (Central), PA; (Figures 1 & 2)

Wampom (Western), PA.

Each apiary contained 20 colonies, ten in standard Langstroth hives (control) and ten in two-colony hives (treatment).

Because the bees were slow to build up and the honey flows in the Northeast were light in the summer and fall of 2005, our goal was to get all of these colonies built up and prepared to overwinter successfully. Little to no honey was removed from the colonies in 2005. Going into the winter all hives had laying queens and adequate honey for overwintering.

Overwintering survival was assessed in May by counting the number of treatment and control colonies that survive the winter. All colonies were prepared for winter in the manner that the beekeeper prepares his/her other production colonies.

Nuc productivity: In the spring of 2006 all colonies were assessed for strength and the potential for nuc production. The colonies were pushed to produce as many nucs as possible without jeopardizing the survival of the parent colony. All of the beekeepers in the project are experienced nuc producers and are capable of making this assessment. The average number of nucs per colony for the control and treatment groups are compared.

Honey production was measured as the pounds of honey removed from each colony. The supers from each colony were removed, weighed and the weight recorded. The supers were then be weighed after extracting, the difference in the supers before and after extracting will be recorded as the production. Honey was removed in late summer of 2005 and 2006 at the time the beekeeper was removing honey from his/her other managed colonies.

Varroa mite levels was assessed in all colonies at least three times (spring, summer and fall) of 2005 and three times (spring, summer and fall) of 2006. Varroa mite levels were also be assessed in all nucs produced from these colonies at least three times in 2006. The technique for assessing varroa mite levels was the standard “powdered sugar roll,” conducted by the local apiary inspector. The PA and NY apiary inspectors are highly experienced in conducting the sugar roll. At the State College apiary we also attempted to assess mite levels using a modified sticky board that provides a daily natural mite drop.

Research results and discussion:

The results from the three different locations yielded dramatically different results. Several reasons likely contributed to the differences. There was significant variation in the nectar flows at the three different locations. While the Morrisville area of NY experienced exceptionally good nectar flows, those in Central and Western PA were normal to below average. In addition, Mike Johnston has had many years of experience with the two-colony hives, while working with these types of colonies was a first for McMillin, Frazier and Cella.

Figure 3. Comparison of standard Langstroth and 2-colonies hives; Johnston Apiary.

Figure 4. Comparison of standard Langstroth and 2-colonies hives; McMillin Apiray.

Figure 5. Comparison of standard Langstroth and 2-colonies hives; Penn State, Wiley Apiary.

Overwintering
The standard and two-colonly hive performed about the same overwintering. The McMillin and PSU apiaries both lost a small number of colonies from both groups but the losses were minor (Figures 4 and 5). Mike Johnston agreed to provide all of the bees and queens needed for this project. Conditions were less than ideal for bee production in the Northeast during the summer of 2005. Due to the strain on his colonies of producing the bees for the project under less than ideal conditions, both the traditional and two-colony hives went into the winter weak and he lost the most hives in both groups. He actually overwintered 14 standard hives, with 11 surviving. Of the 11.5, two-colony hives that went into winter, eight survive. This does represent 16 clusters of bees however, since we were comparing the overall performance of the traditional hives verses the two-colony hive, our comparisons are made on a per unit (hive) basis.

Nuc productivity
The McMillin apiary did not produce excess bees and brood from either the traditional or two-colony hives. The PSU apiary produced 20 frames of brood and bee from the traditional hives, or slightly more than the 17 frames produced from the two-colony hives (Figure 5). The Johnston apiary however, produced far more frames of bees and brood (52) from the 11 standard hives than the two-colony hives, which produced only eight (Figure 3). This was due in part to the poor overwintering, particularly of the two-colony hives. The colonies built up well but the traditional colonies built up faster and thus produced more excess bees and brood.

Honey Production
The comparison of honey production between in the two different systems at the three different locations can be seen in Figures 2, 3 and 5. While the two different systems produced about the same amount of honey in the PSU apiary, the two-colony hives produced only about a third as much honey as the standard hives in the McMillin apiary (these totals include honey produced in the fall of ’05 in addition to the honey produced in ’06), but the two-colony hives produced nearly twice as much in the Johnson apiary. This was most likely due to several factors. The two-coloney hives are very prone to swarming. The Johnston two-colony hives were slow to build up. This was evident in that they did not produce many extra frames of bees and brood. These colonies most likely did not swarm as much as those in the McMillin and PSU apiaries. When those in the Johnston apiary did swarm they were replace. In the McMillin apiary colonies that swarmed were not replaced.

Varroa mite levels
During the course of the project we did decide to treat the colonies with formic acid to control varroa mites. We concluded that this was an additional variable that could interfere with our ability to evaluate the production performance of these two systems. Mike Johnston opted not to treat his colonies.

Conclusion
All cooperators agreed that managing the two-colony hives as overwintered units was difficult. If they overwiner well, they built up quickly and were prone to swarming. Re-queening one side of the two-colony hive was somewhat difficult. Because the workers mingled in the shared supers, they had access to the pheromones of the one queen present in the queen-right side of the two-colony hive. This made them less willing to accept a new queen if one half became queenless, which sometimes happens after swarming. Additional care needed to be taken when inspecting the colonies to be sure brood boxes were not reversed. If so, this would result in two queens in one unit and no queen in the other.

The construction of the two-colony hives could be improved if the internal divider that separates the two colonies could be made removable. If one of the two colonies dies, the beekeeper could then remove the divider and allow the colony to expand into entire hive. It would also be useful if the bottom boards were not permanently attached to the brood box. Reversing brood boxes is a useful management technique that is not possible in this situation.

In general, the two-colony hives did not outperform the standard hives in this limited one-year test. From previous studies and reports, including work conducted by Mike Johnston, the two-colony system may be more productive if the overwintered clusters are used to repopulate standard hives in spring and then reestablished with a few frames of brood and a new queen or queen cell. Earlier studies found that under these circumstances the two-colony hives could produce more bees and even more honey. But the two-colony hives were not more profitable than standard hives when they were overwinters and maintained as production colonies in the manner used in this experiment.

Research conclusions:

Based on the findings of this limited one-year experiment and the earlier work with this type of system, we believe that there are applications for two-colony hives, especially in the production of bees that can be used for the replacement of dead-outs from winter losses or in the sale of bees to other beekeepers who have lost colonies for want to increase their colony numbers. Due to the high levels of losses being experienced by beekeepers in recent years, replacement bees are becoming increasingly valuable and are in high demand. Any system or approach that helps increase the availability of honey bee colonies to beekeepers in the Northeast will be very valuable.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

The results from this study were presented at the Pennsylvania State Beekeepers meeting and at the Eastern Apiculture Society in Delaware. A publication will also be prepared for one of the major beekeeping journals.

An additional project to test the two-colony hives system in spring only for bee (nuc) and honey production would be advisable.

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

An additional project to test the two-colony hives system in spring only for bee (nuc) and honey production would be advisable.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.