Trapping Feral Honeybee Swarms

Final Report for FNC02-397

Project Type: Farmer/Rancher
Funds awarded in 2002: $17,452.00
Projected End Date: 12/31/2004
Matching Non-Federal Funds: $23,620.00
Region: North Central
State: Missouri
Project Coordinator:
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Project Information


The three producers/beekeepers in this project are relatively small, part time beekeepers. We all qualify as “hobby level” beekeepers (1-40 hives) and possibly “sideliners” (50-199 hives), averaging ten years of experience in beekeeping. In the second year of this project, four additional participants from the Jackson Area Beekeepers Club were added during the 2004 season increasing both the number of project locations and the data collected from trapped swarms. Their operations were practically identical to our operations.

The participants in this project all depend upon income from other sources other than our honeybees. Honey produced from our hives is marketed through our own efforts and personal networks and seasonally through farmer’s markets and craft fairs. Our personal land base is small (less than ten acres) though honeybees have the potential to cover 2,560 acres per location. Most of our hives are located at our home location with some hives located on other farms in the area.

The principles of trapping feral swarms have been practiced by the participants for the last five years, but not on a disciplined regime as carried out in this SARE project, or to the level of our participation. Our SARE grant allowed us a marvelous opportunity to move the bulk of our operations into a sustainable practice of trapping feral honeybees for their expected resistance to parasitic mites and reducing our dependency upon non-renewable resources (chemical miticides), and decreasing the likelihood of chemical in wax and honey. In addition, fewer chemicals reduce the negative impact and potential side effects on the health of the honeybees and the possible danger to the beekeeper. Further, the consumer’s image of honey is major concern as well. We seek to promote the increased natural qualities of producing our honey without the dependency upon non-renewable, potentially dangerous chemicals and pharmaceuticals.

The project goal was to trap feral honeybee swarms using pheromone-based swarm traps (bait hives, catch boxes), hiving the swarm conventionally, then monitoring the mite loads to identify mite resistant colonies. Mite infested colonies would either be moved a minimum of two miles away and treated conventionally, or left untreated (and eventually to die), leaving a bee yard with resistant colonies. These colonies would then be utilized to produce resistant queens. In time, as little as one season, it would be possible to raise a naturalized, locally adapted strain of mite resistant honeybees reducing the dependency upon chemical miticides and creating a more sustainable operation.

In a nutshell, box style pheromone baited swarm traps were hung in trees and remote locations, monitored during daylight hours two or three times a week to see whether or not a swarm was caught. When a swarm took up residence, the trapper returned to the location at night. The entrance hole was plugged under the cover of darkness (when all the foraging bees come home), and the trap removed and brought to the trapper’s bee yard. The swarm traps contain full depth, brood frames on which the queen lays eggs. The frames are easily removed from the box style trap and transferred to a beehive. We used conventional, Langstroth hives built to receive these frames. The bees attached to the frames and transferred to the Langstroth hive readily take up the new location/hive as their new home and begin the process of gathering nectar and raising more brood.

In detail, several types of box style traps were utilized for this project. Waxed cardboard “nuc” boxes were preferred for their lightness of weight, but did not adequately house large swarms (bees clung to the outside making removal and transfer difficult). The waxed cardboard also proved to be susceptible to weather and did not last more than one season. Wooden “nuc” boxes were modified to hang on trees and were used more successfully, but they were quite heavy to carry up and down a ladder. Pre-formed, wood fiber swarm traps were also quite successful, providing ample room, but these are no longer available from the manufacturer. Plastic traps were attempted but were totally rejected by the honeybees. All of the boxes are available through any one of several beekeeping supply catalogs.

We purposely did not choose “cone” style traps, as they have to be emptied within 24 hours of catching a swarm to prevent the swarm from building their own honeycomb. With 100 traps to check in far flung locations, box traps gave us the greatest flexibility.

Traps were baited with nasanov based pheromone lures acquired also through beekeeping supply catalogs. The lures hung in the traps about 1 inch above the opening. Full depth brood frames were added to each box to allow the bees a place to start drawing out wax honeycomb and to ease of transfer of bees from the trap to the Langstroth hive.

Traps were hung in trees, approximately 8’ high, using large spikes, supporting branches, and secured with baling twine. Multiple locations were selected from successful trapping sties in previous years, plus permission was solicited from amicable land owners, businesses, golf courses and utility companies to participate and assist us with this project. At each location, several traps were hung to increase the availability of trapping opportunities. Depending upon the location and places to hang traps, a minimum of one trap was hung, and a maximum number hung was four traps.

When a swarm took up residence, we returned to the trap location at night, when all the foraging field bees returned home. The entry hole was plugged with a paper towel restraining all the bees inside the swarm trap.

As a swarm moves into a swarm trap, it will immediately begin drawing wax comb, and if the queen is on older queen, she will commence laying eggs as soon as comb is deep enough. New queens may take a week to ten days to start laying eggs. Once the swarm moves in, foragers will then go out and start brining in nectar and pollen. There is no urgency on the beekeeper in removing the swarm from the trap; however, delaying removal increases the likelihood of burr comb making transfer to the Langstroth hive more difficult. Most of our traps were emptied within two or three days or detecting the swarm’s presence in the trap.

Upon taking down the trap, as long as our ladder propped up against the tree, another freshly baited trap is hung in its place to catch another swarm. We learned to bring a fresh trap whenever we went out at night to take down a trapped swarm.

The bee-filled trap (with the entry hole plugged) was set in the back of a pick up truck and brought to the bee yard, set in place where we wanted the new swarm to reside, and while still dark, the plug was removed. The following day we returned and found the bees making their orienting flights to learn their new location. The swarm traps were then “smoked” to quiet the bees, opened and the frames were transferred to a conventional Langstroth hive.

As long as the queen remained on one of those frames, the rest of the bees will stay with her, even as we move the frames to a different structure, in this case, the Langstroth hive. Bees flying in the area find and follow their queen by scent. The trap was laid off to the side, about ten feet away. Residual bees flew to find their queen. The abandoned trap was loaded with new frames (the pheromone lure is still effective) and the trap is reused at another location to catch another swarm.

The Langstroth hives were set on screen bottom boards which allowed the insertion of “sticky” boards underneath the screen. Sticky boards are sheets of stiff plastic coated with liberal amounts of vegetable oil. As parasitic mites fall off the bees and down through the screen bottom, they stick to the oil. Varroa mites, visible to the unassisted eye, can be counted and a relative assessment of the colony’s mite resistance can be established.

Beekeepers from the Jackson Area Beekeepers Club were utilized for both conversational as well as consultative input. The project participants also visited with members of the Parkland Beekeepers Association for input. A presentation was made to the Parkland Beekeepers, including a segment of their class on “Beginning Beekeepers.”

In the second year of this project, four members joined the project in increase the diversity of trapped swarms. In our need to find multiple trap locations, businesses that catered to public gatherings (gold courses, churches, and parks) were solicited. They gladly agreed for us to install traps (at no charge), as they wanted honeybee swarms removed from the area reducing their liability. Likewise, a list of swarm calls from residential sites was revisited and homeowners were asked if they wanted swarm traps installed to remove unwanted swarms.

The Missouri Department of Conservation was solicited for trap locations in the Apple Creek Conservation area. AmerenUE (an electric utility/company) was solicited for trapping sites on their vacant lots that did not contain equipment. Both agreed to help us on this project.

Further, referrals were taken from calls made to the local fire departments, police departments including animal control, the Extension service, exterminators and nervous homeowners.

One of the questions this project probed was, “Are there feral swarms surviving in the wild, living unassisted by beekeepers intervention, or did the mites wipe them all out?” It is a widespread assumption that all feral colonies were wiped out since the mid 1980’s invasion of the mites.

There are also some people claiming feral swarms are making a comeback, a resilient return due to natural selection. We are of this later group.

We found feral colonies living in certain areas and absent in other areas. We caught more swarms in urban areas (mostly older, downtown areas) than agricultural areas. We found differences from one county to another county, with the greater number of swarms caught closer to the Mississippi River (Cape Girardeau, Perry and Scott counties). The number of swarms caught decreased as we monitored traps in Bollinger and Wayne counties. We have no reasonable explanation for this observation.

We found in several locations, each with four traps available to the bees, that one particular tree at the location was preferred by swarms for reasons we cannot fathom. After the trap was removed and placed in the pickup truck, a fresh new trap was hung in its place. The next swarm to come into the area looking for a residence was drawn to this same tree, even though several other traps of similar materials were available. We found this behavior an interesting observation and may offer clues to successful trapping strategies in the future.

In both years of this project, 100 traps were hung in over thirty locations, with the number of traps per location ranging from one to four. Trap locations were located a minimum of two miles apart. Some locations caught multiple swarms where other locations caught no swarms. In the first year, 2003, sixty swarms were caught. This is in line with our previous results, finding that slightly more than half of the traps set will catch swarms, even in location with multiple traps.

The second year we spread out 100 traps to forty-one locations with the inclusion of other beekeepers and moving traps from locations neglected in 2003 to fresh locations. Sixty nine swarms were trapped. We are quite pleased with the number of swarms caught, indicating an enthusiastic movement of honeybee swarms looking for nesting sites. Unfortunately, we cannot discern if these swarms were truly feral or if they swarmed from an undetected, managed colony in the area of the trap.

Year, Number of traps, Number of locations, Number of swarms
2003, 100, 30, 60
2004, 100, 41, 69

Conclusion number one: Trapping swarms is a viable means of increasing the number of colonies without incurring any cost for the bees (as in buying a package of bees in the spring).

Traps were hung in early April. Swarms caught in April and May took off and produced a crop of honey. Swarms caught in June and July needed feeding and some of the last swarms caught failed to thrive and were lost over the following winter, if they managed to make it that far. Some of the early swarms also declined, due in part to what we think was attributed to the age of the queen, but we cannot rule out the effects of mites.

By late June and early August, we also began to see abandoned colonies where the entire colony absconded and left. These were mostly the last swarms we caught. No honey stores were left behind. None, or very little brood was present, indicating the possibility that the queen was either poorly mated or still a virgin queen. We surmise these colonies were “robbed out” by adjacent colonies. The robbed hives were smaller (only one brood box) and not as strong. After the robbing episode, it is not uncommon for colonies to dwindle and drift other colonies and give up their original location. The queen is lost somewhere along the way.

In 2003, of the sixty swarms we caught, we had forty-nine colonies on August 1st to monitor for mites. Of those forty nine, thirty three were carried into the winter. The fall was extremely dry and the fall honeyflow did not materialize to our expectations. Of those thirty three hives wintered, only nine would survive. Losses seem to be attributed to starvation. While we find these losses to be discouraging and embarrassing they are a reminder that though swarms are free, they still require and will incur maintenance costs.

Year, Swarms caught, August 1st count, Number wintered
2003, 60, 49, 33
2004, 69, 60, 49

Conclusion number two: Late swarms need to be hived in a separate area, or combined with weaker colonies to prevent robbing and losses. Irrespective of the fall honey flow, these late swarms must be fed, a mistake we rectified in the 2004 season with purchases of type-55 high fructose corn syrup.

Also in August, sticky boards were inserted and mite loads were counted on the hives that still contained bees. The first year we counted mites in fourth nine hives and the second year we had sixty hives to sample. We have concluded that counting mites drops over a 24 hour period, on a weekly basis, is an extremely tedious job and requires more time than we originally anticipated. Mites were counted once each week, over a 24 hour period, for four weeks. The results were then averaged.

It was our initial thought that mite counts were fairly objective, but differences in colony strength have led us to conclude mite counts are highly subjective and relative.

In terms of mite resistance, not all swarms caught showed a resistance to the presence of mites (as evidenced on a sticky board). This took us by surprise as we presumed all feral swarms had to have some kind of resistance to disease and mites or else they would die without chemical intervention. It was our assumption that the number of varroa mites on a sticky board would be a leading indicator of their resistance. And then it is possible that some of the colonies we caught came from a susceptible, managed beehive over the hill that had been treated with miticides and were now open to mite infestation.

However, some of the mite infested feral swarms demonstrated a strong vitality, despite the presence of mites, raising the issue of mite resistance versus mite tolerance. Swarms hived earlier in the season had a greater likelihood of mite infestations than later swarms. This makes sense as earlier swarms have more brood cycles. However, not all mite infested swarms died out. Some hives seemed to do just fine with mires present.

Year, August count, <2 mites, 2-10 mites, 11-50 mites, 50+ mites, Winter survival
2003, 49, 12, 15, 12, 10, 9/33
2004, 60, 19, 11, 9, 21, ?/49

Conclusion number three: The mere presence or absence of mites does not always indicate the level of resistance. However, one may presume with strong confidence that the absence of mites is a favorable sign. What may be the real indicator of resistance/tolerance is the ability to come through a winter and survive the following spring.

And another problem we encountered but did not anticipate: what really constitutes a specific level of mite infestation? What we discovered, to our ignorance, is that mite numbers are relative to population. Finding two mites in colony housed in a single brood box should cause more alarm than finding two mites in a colony housed in two brood boxes. So our measurements are relative, but still, low numbers of mites signal an acceptable level of resistance. We found it physically impossible to begin implementing other methods of counting mites (soap wash, powdered sugar toll, etc.).

Conclusion number four: Mite counts may be over rated, they are time consuming and definitions of “economic threshold” may be entirely too subjective. Other methods of taking samples of bees and washing/straining the mites would give a more accurate picture of the percentage of mites.

It is our conclusion that some colonies are resistant to the presence of mites (low mite counts) and that some colonies are tolerant to the presence of mites (higher mite counts yet remaining strong and vital). And then there are those colonies that die from the complications that high mite loads bring.

Mites present two problems, one being they weaken a colony, but the second is that weakened colonies become susceptible to viral and bacterial diseases. Apparently some swarms tolerate the presence of mites without succumbing to the diseases. The vulnerability to the diseases is seldom known until the winter months when the stress of cool, damp weather that winter brings with it. For this reason, this project was intentionally carried over for two seasons.

Conclusion number five: There may be no real indicator of resistance without extensive and expensive professional laboratory analysis. We’re not sure if our resistance is genetic or behavioral, or both. In the end, if bees are untreated and they survive, particularly over the winter months on sufficient feed and adequate ventilation, it is our thought that natural selection could take place and move the beekeeper into sustainable practices. However, one would have to endure significant losses of hives previously protected by chemical applications.

The swarms were hived in bee yards with conventionally treated colonies that no longer received treatments, and thus were exposed to mites. Most of these untreated, established colonies died out, a tragic waste of resources but a necessary cost in moving to resistant stock.

Overall conclusions: We have colonies that show a remarkable resistance to mites and disease. The origins of these swarms definitely remain in question. While the number of swarms caught brings us great hope, the number of colonies that survived through the first winter, with a seemingly resilience to mites and disease, is not as great as we expected. We alleviated one of the aggravating factors and we hope for greater survivability. The mechanism of their resistance remains unknown and counting phoretic varroa mites gives a relative indicator of their potential resistance. Survivability, irrespective of mite counts, seems to be the one true indicator of resistance.

Discussion: A point of contention arose in our beekeeper’s club and internet discussion groups: where do feral swarms come from? Could it be, as tracking a swarm’s origin or determining the mother colony’s location is next to impossible, that some of the swarms we caught originated from treated, managed, chemically-dependent bee hives cared for by unknown and undetected beekeepers in the areas of our trapping locations?

The answer of course is yes. Swarm traps are effective for a radius of one mile. We could not account for every colony tucked away on the backside of every farm, but it is our thought that there are simply not that many hives of this category.

It is also suggested that feral swarms may live on year, but not two years, before they succumb to mites or viruses. Did we catch first year swarms? Since swarms move relatively mite free, it might be possible that a vulnerable colony, under attack from mites, sends out a mite free swarm (which we caught). The originating hive dies out, as it is susceptible to mites. The swarm establishes itself without the added stress of the mites, and then builds up in population. But as the population of the bees grows, so does the mite population. And eventually, the colony sends out a mite free swarm before the established hive crashes and dies from mite infestation.

This theory would substantiate the catching of swarms from unattended and untreated hives, but because the colony does not possess a genetic or behavioral resistance the mites, this becomes more an “escape and avoidance” method of survival. If we catch these susceptible swarms, provide ample room and decrease the swarming impulse, then we should not be surprised when these swarms die in our bee yards.

Since swarms travel relatively mite free, the presence of mites is magnified when the colony is settled and raising brood (this is where mites reproduce and multiply). Therefore, determining if a swarm is from mite resistant stock takes time. The swarm must settle and raise brood. When a swarm is trapped, and if the queen is old (hence, mated and ready to lay eggs), the earliest emergence f brood will require three weeks time, the time of gestation from egg to emerging adult. How many brood cycles before mite levels are discernable is unknown to us. However, mite levels peak in August and September and this is when we made our assessment. The real test is survivability, especially over the winter months.

We experienced a wide variety of results. Some swarms proved to be quite productive and some failed to thrive (perhaps headed by unmated, virgin queens or a very old queen that is rapidly going down hill). It must be remembered that we are looking to trap a genetic base of mite resistance and that swarms identified as resistant should be used for producing new queens. Had we known how the later, weaker swarms would be robbed out and the hive abandoned, we would have combined swarms together to make one viable colony instead of losing two weak colonies.

The earliest swarms caught (“prime” swarms) are usually headed up by older queens. Older queens are less productive than younger queens found in “after” swarms. A colony may swarm several times in the span of three or four days, and again even later in the season if conditions warrant congestion and over crowding. The age of the queen is a variable to concretely determining the vitality of the swarm.

At the conclusion of our first season, we experienced a drastic drought during August and September. The fall honey flow did not materialize and colonies went into a harsh winter with insufficient stores by honey (their food reserves). We lost many hives, many of them smaller, later swarms.

As a result, we vowed to increase the feeding of sugar syrup for the next season (an added expense) but we did not require additional second year materials supplies for the hives that died (a savings!). Therefore we had no problems of carrying out this project within our budgeted amounts.

A second, unforeseen blessing came from the hives that did survive the first winter despite being under fed. Not only did we have mite/disease resistant colonies, we also had hives unintentionally tested for winter hardiness (or a resistance to the viruses and diseases attributed to the mites). Mite levels were tested and counted through the 2004 season. Again, we found some of the hives with mites showing a marvelous vitality. Some hives held their own and perhaps really needed to be requeened.

Final advice, if asked by another producer, would be the following:
1) There are swarms to be trapped, though not in all areas. Therefore, set traps and catch the swarms that are in your area. Hive them during your first year, monitor the mite loads and feed for adequate winter stores, especially the late swarms.
2) Discern which hives have mites and which do not, and then carry all of the hives through the winter. The stress of the winter will weed out the weak colonies and lift up those colonies that are resistant and tolerant to mites and the diseases they introduce to the colony.
3) Be prepared to lose some of the colonies that are susceptible to mites
4) In the spring of the second year, from the surviving colonies, raise your own locally adapted queens and begin requeening your bee yards. Queen rearing location should not contain treated hives that would be raising susceptible drones. After the spring honey flow, take your established hives make summer splits. Feed to build up for the fall honey flow and bring them into the next spring.

Project Impacts:
Trapping feral swarms presents the beekeeper with “free” bees. If caught early enough, they may reward the beekeeper with a small honey crop that same year. This economic benefit is perhaps the most obvious advantage to this project. Every year, beekeepers spend a great deal of money buying “package” bees from southern producers. The cost for shipping, and for the bees themselves, continues to go up squeezing profits and adding additional expenses. At the present time, a three pound package of bees costs between $45 to $65 delivered, depending upon availability.

On a deeper, sustainable plane, trapping feral swarms for their genetic or behavioral resistance to mites and the diseases they carry reduces the cost of chemical antibiotics (Terramycin most notably) and miticides Apistan and Check-mite. When you measure the actual cost of the pharmaceuticals, roughly $5 to $6 per hive, and the additional labor for installation and removal, perhaps another $5 per hive, it does not seem prohibitively expensive for smaller producers.

However, we are finding mites developing resistance to these miticides and an increased need for stronger, more potent chemicals. Alternatively, we are also looking at other options (formic acid) which have their own challenges of application and safety issues. There is a rise in the less effective “soft” chemicals. Additionally, we are finding chemical residues and harmful side effects of the conventional chemicals, which to this point have not created a problem. But then, not so long ago, Alar was also seen as an innocently beneficial chemical needed to bring consumer acceptable apples to the marketplace.

We perceive that larger impact of this project to be somewhat limited to the beekeeping community. More specific, this project appeals to the smaller hobby level and sideliner beekeeper (they have the time to trap and count mites). As beekeepers numbers have decreased over the last three decades, the scope of this impact is limited. However, as most of the beekeepers preferred to quit rather than fight the mites (and be forced to purchase expensive chemical treatments), this project may entice some people to consider a return to beekeeping. In this respect, the prospects of sustainable agriculture may increase and expand the number of beekeepers thereby enlarging the impact of this project.

As consumers become more conscious of food additives, honey will be required to defend its perceived natural qualities. If chemical residues are ever found, the integrity of honey might never by recaptured.

And one must also keep in mind the importance of beekeeping and pollination relative to changes in crop or livestock production. Recent estimates conclude honeybees contribute $15 billion (that’s with a “b”) worth of produce grown in the United States. We need the bees, and we need beekeepers who can keep their bees. The more sustainable beekeeping can become, the more we can continue to provide bees that pollinate other crops to the benefit of the farmer and livestock producer.

Thus far, we have shared our findings with two bee clubs (Jackson and Parkland) and given programs in these local clubs in the late winter of 2004. One program was for beginning beekeeping and the other was for “Spring Bee Days.” With our project still in the theoretical stages at that time and lacking solid conclusions, advertising for this program was minimal. We also found trapping swarms was not something first year beekeepers were ready to attempt.

Interest in beekeeping production practices runs seasonal, with the highest interest in the springtime and late winter. With our successes coming in the latter part of our second season, we are now poised to offer a field day in Jackson on Saturday March 5th, (sufficiently early to allow participants time to prepare for swarm catching) hosted by the Jackson Area Beekeeper’s Club.

This day is already on the calendar. We hope to have fifty producers in attendance. We will use the network of Extension offices in Southeast Missouri, Southern Illinois, Western Tennessee and Northern Arkansas to advertise, plus run advertisements with the respective state beekeepers associations. We have reserved $550 in our budget for the promotion of this event.

We are also in the planning stages to offer our insights at the spring meeting of the Missouri State Beekeepers (either March 12th or 19th, likely in Cape Girardeau or Poplar Bluff).

As beekeepers are mostly part time producers and schedules are complicated by competing obligations, we will offer a printed version of the proceedings available by First Class mail. A website on the internet has been developed and will be used to advertise the field day as well as the material. This can be found at

In this next year, 2005, as we continue our practices of trapping swarms and raising queens, we hope to create a video version of our project, recreated as the season progresses showing in detail how we bait the traps, hang them in selected locations, check on them, retrieve trapped swarms and transfer the bees to the Langstroth hives, monitor mites and select hives for their mite resistance.

Funding for this video project will come from the Jackson Area Beekeepers Club and will likely include its members in the production.

For further outreach, it is also our intention to continue to refine the process and make these updates available in printed form. This booklet will also contain more pictures and details than we have posted on the website.


Participation Summary
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.