The Art of the Trap-out
When it comes to removing honey bee colonies from unwanted places, the trap-out can be a useful method, but it requires time and a good understanding of the biology of the beehive to succeed.
Colonies of bees often utilise hollows in trees to establish their hives. These are the natural nesting places for Europen honey bees in regions of the world where Apis Mellifera are endemic. In areas where bees are an introduced species, they are considered feral, occupying the nesting sites of native creatures.
Even in locations where bees are native, there are often some important reasons to remove them from tree hollows. Sometimes these colonies end up close to human activity and pose a stinging risk. Feral or wild bees also pose a biosecurity risk for beekeepers as an unmanaged hive can harbour pests and diseases that can impact profoundly on the beekeeping industry.
The main choices for removing bees in this situation include cutting them out and forcing them out, but the option we will focus on here is the "trap-out" method. This technique allows bees to exit the nest but not return, and in turn, the trapped-out bees are offered an alternative home.
The art of the trap-out lies in understanding bee behaviour, failure to do so will result in wasted time and effort. The timing of specific steps in the process is crucial, and it is essential to know that there can be several factors that will impact on the success or failure of the trap-out.
Blocking All Exits
The first step in a successful trap-out is to eliminate all exit points from the hive, bar one. This task is not straight forward when dealing with trees as hollows can extend in unpredictable directions, and while the bees may be coming and going from only one specific point, there are usually other holes onto the cavity not in use.
One useful technique for discovering extra exit points is to apply some smoke to the lowest hole and look for any smoke and or bees escaping from other locations. Be aware that too much smoke inside the nest can kill bees, so it is best to use as little as possible and be patient for the results.
Once identified, all of the exits need to be blocked except for the main exit point. Steel wool is a good option for blocking holes as it can be easily pushed into tight spaces, and the bees are unable to chew through it. Silicon can also be used but is messy, takes time to dry, and some bees will get likely get stuck in it.
Expanding foam should be avoided for blocking small spaces as it can expand into the nest entrapping bees and, once dry, the bees can chew through it. For large openings, expanding foam can be useful. To prevent the bees chewing through the expanded foam once set, some aluminium insect mesh can be forced into the opening first, followed by some newspaper or other material to prevent the foam expanding into the nest itself.
The Catch-box
The catch-box is designed to entice the returning forager bees when they find themselves trapped-out with nowhere to deposit their nectar or pollen. It is not intended to attract the bees exiting the hive as they will immediately depart to forage, defecate, remove corpses or foreign objects from the hive. Therefore it is crucial for the entry of the catch-box to be as close as possible to the main entry/exit of the hive.
The catch-box is usually a 5-frame nuc box or a standard eight or ten-frame brood box and will often require the beekeeper to be a little inventive in the construction of a platform to support it. The platform should be sturdy and capable of holding the weight of a honey-laden hive. As the trap-out process can take several weeks, if there happens to be a nectar flow, the box can quickly fill with honey.
The design and positioning of the platform should also take account of when the catch-box is ultimately removed as this task is usually done after nightfall and off a ladder. The potential weight of the catch box can make this job difficult and potentially dangerous.
The Trap-out Funnel
After blocking all of the alternative hive exit points and the catch-box has been put in place, a trap-out funnel needs to be placed over the main exit. The trap-out funnel allows the foraging bees to leave the hive but fools them into thinking that they can not re-enter the hive. For this reason, the funnel needs to be constructed from an aluminium or steel mesh that the bees can see and smell through but are unable to chew through.
The bees will exit from the tip of the funnel, but on returning to the nest, they will attempt to re-enter at the base of the cone. They will be able to see and smell the hive but will be unable to get in. A funnel made of solid material will fail because the bees will quickly work out how to re-enter the hive via the exit hole in the tip of the cone.
The trap-out funnel should be at least 30cm long, which is long enough to prevent the bees from finding their way back into the hive via the hole in the top of the cone. It is vital that the exit hole in the funnel is large enough for at least two or three bees to be able to exit at once, allowing undertaker bees to remove dead bees from the hive without clogging the funnel. A clogged funnel will lead to mass fatalities.
Be aware that once the trap-out funnel is in place, a surprising number of bees already out of the hive will start to mass at its base, unable to re-enter. Therefore the catch-box should be installed before the trap-out funnel is attached.
Luring the Trapped-out Bees
With the catch-box securely in place and bees starting to accumulate at the base of the trap-out funnel, they are unlikely to immediately begin considering the catch box as a potential new home without something to attract them in. The best attractant is a frame of open and capped brood placed inside the catch box along with some frames of drawn comb.
Open brood emits an odour similar to queen substance and is highly attractive to worker bees. Once discovering the brood frame, worker bees instinctively begin to care for the unborn bees and will quickly start to orientate to the new hive box. The provision of the drawn comb will give the forager bees somewhere to store their pollen and nectar.
The temperature of the brood comb is regulated by the colony, and open brood is particularly susceptible to death if not maintained at 34 degrees Celsius. Die-off can be a problem if performing a trap-out in cool weather because it will take time for the trapped-out bees to enter the catch box and start to cover the brood comb.
One method to maintain the temperature of the brood is to add a frame already covered in nurse bees. To achieve this, the brood comb can be removed from the donor hive and placed in a nuc box several meters away and left for at least 30 minutes. Over this period any older bees will fly back to the donor hive, leaving the brood comb covered only with young nurse bees. Nurse bees are not defensive of the brood, and they will be readily accepted by the trapped-out bees; therefore, there is unlikely to be any conflict in the bringing together of bees from different colonies.
A New Queen
The trapped-out bees will, of course, be queenless as the queen from the original hive will not exit that hive for some time. The provision of open brood to attract the trapped-out bees into the catch box will also present the colony with an opportunity to create a new queen, which any queenless colony will be eager to do to ensure the continued existence of the new hive.
The absence of any queen pheromone circulating throughout the new hive will result in the bees in the catch box almost immediately realising that they are queenless and they will most likely start to build emergency queen cells within the first 24 hours. While the colony can create a new queen from larvae up to three-days-old, the best queens come from younger larvae, so it is ideal for there to be some eggs in the brood comb. Alternatively, for greater control over the genetics of the new colony, introduce a new queen or a queen cell from a known source.
If a queen or queen cell is introduced to the catch-box, it is essential to check the new hive after one week to remove any emergency queen cells. Failure to do so may result in the catch box swarming or a newly hatched queen superseding the desired queen. After a week, all eggs will have hatched and be more than three-day-old and therefore unviable for queen creation. Regardless, if possible, another check for queen cells would ideally be made at around day ten of the trap-out.
Understanding the Biological Time-frame
In addition to the timing of adding and checking on a new queen, there are other time-critical actions essential to the success of a trap-out. Understanding the life cycle and behaviour of bees will determine each step of the process.
Let us examine the perfect trap-out scenario, including what unfolds inside and outside the nest. For the first three weeks of their life cycle, bees remain inside of the hive. At around three-weeks-old, they leave the nest each day to forage. Therefore in the first two days, most of the oldest bees will become trapped-out. This results in two main implications; 1. the population of the hive rapidly decreases, and 2. nectar, pollen and other resources stop coming into the hive.
The queen and colony will quickly sense this change in hive dynamics, and the production of new bees will slow. The queen may start to slow her laying, and the colony may begin to eat the eggs to control the population balance to resources available. Within a week or so, the queen will most likely cease egg-laying altogether.
The last egg laid by the queen will take three weeks before it hatches, which is when the clock starts ticking on the trap-out. In a usual situation another three weeks after hatching that bee will be ready to leave the nest and start foraging, however, when there are no other bees bringing in resources, no nurse bee duties to be performed, the last bee to hatch will most likely head out of the hive at only about two weeks of age.
Based on these calculations, after five weeks, the hive would be stripped of its entire population, and the queen and remaining bees would have swarmed from the original hive. The trap-out funnel could then be removed, allowing the new colony, made up of the trapped-out bees, to re-enter the original hive to rob the last of the honey stores; a job they could perform within one or two days. At this juncture, the trap out would be complete.
The More Realistic Time-frame
In reality, as the trap out progresses, the process described above will almost certainly begin to derail. The more likely scenario, as the population plummets inside the original hive, is the infestation of pests and even the possibility of disease, like chalkbrood, which flourishes inside a stressed colony.
Small hive beetle is likely to have the most substantial impact as they can quickly overwhelm a beehive causing a catastrophic slime-out. A slime-out could quite quickly happen as early as a week after the beginning of a trap out, and that would result in the swarming of the original queen and remaining bees as they abscond from the hive.
As the queen exits the trap-out funnel, it would be unlikely that she would move into the catch-box as that would almost surely be a fatal move for her as it is now a completely independent colony with a new queen.
In this scenario, with the original hive abandoned, the trap-out would be complete, and the catch-box relocated.
Concluding the Process
With the colony removed, the final step in the process will depend upon the reason for removing the beehive in the first place. If the objective was to free up nesting space for native animals, then there is little to be done.
Most likely, wax moth, cockroaches and other vermin will destroy the remaining combs. However, the smell of the hive and particularly the queen pheromone will linger, and there is a high probability of the cavity attracting another swarm of bees. Therefore, if the hive removal was for safety reasons, it is crucial to fill the cavity or block the entrances to avoid reinfestation. If the cavity is filled, a new colony will not reoccupy the space.
To physically cut-out a beehive is a far more straight forward way of removing a hive and saving the bees, however, if it is not possible to expose the nest, a trap-out can be a successful alternative. The process can be time-consuming, requiring multiple tasks performed over several weeks. Often external factors will alter the predicted timeline and compel the beekeeper to respond as necessary.
As a way of acquiring a new honey-producing beehive, there are much better alternatives to a trap-out. As a way of saving a colony of bees, a trap-out is one more method a beekeeper has at their disposal.