Small, Pesky, and Rather Clever
The Small Hive Beetle, commonly referred to as SHB, is recognized by many beekeepers as a serious threat. It was introduced into the US, via Florida, in the 1990’s from South Africa. While originally limited to certain states in the US, it has now spread to many others.
SHB is a brown or black beetle and its larvae can grow to around 11 mm. Adults can live up to six months, with females laying up to 2,000 eggs in their lifetime. The larvae, as we will see, are the main source of damage due to their appetite for everything in the hive.
Impact on Bee Colonies
Finding a beetle or two in your beehive isn’t particularly unusual. Indeed, most types of beetles will come and go in small numbers, without any issues.
The Small Hive Beetle is different.
Consider these facts:
- Its larvae eat wax
- And pollen
- And honey
- And brood
- And eggs
Within a beehive that is pretty much everything so that’s pretty bad for the bees. But it doesn’t stop there.
SHB larvae feast on the contents of the hive for up to 16 days, as they mature. Then they will leave the hive to pupate, often in the soil right under the hive.
So even when the larvae have left the hive, they are still a problem waiting to happen. Why? Because when the adult beetle emerges from the soil after about 4 weeks, it heads for the nearest hive. And that hive is right above! There they lay eggs and the cycle continues.
Here’s another less-than-appealing thing to consider. The beetles defecate in honey! If that’s not bad enough – for obvious reasons related to what you might like to serve on your toast – it also causes honey in the hive to ferment, after which it will ooze out of the comb.
SHB = bad news!
An Extraordinary Interaction with Bees
Stronger colonies often defend themselves successfully against SHB, as we will see. However, there is a real threat with weaker colonies, which may eventually just leave the hive. The number of beetles can rise quickly, reaching as many as 10,000.
There can be a fascinating dynamic between bees and SHB. The beetles search for cracks and crevices in the hive. Since the beetles are too tough to attack directly or to sting, bees often respond by trapping the beetles in confinement areas they build with propolis. The bees then “stand guard”, making sure the beetles can’t escape. Amazingly, beetles can be held captive this way for months.
But that’s not the end of the story. When confined in this way, the beetles have another fascinating trick up their sleeves.
Studies have indicated that the beetles can reach out of their confinement area and “tickle” the bee. This is a re-enactment of what bees do naturally when they use this technique to “beg” for food from other bees. This behavior by beetles has been seen to work, and a guard bee can release a drop of honey for the beetle to eat. Here’s an extraordinary video showing this (see around the 35-second mark).
Vulnerable Situations
In general, bees can cope with the population of SHB on their own and assign workers to take care of the issue, using the bee prisons mentioned above. However, the smaller the colony the less likely they are to have sufficient numbers to defend against SHB.
An example of this is after a package of bees or a nuc has been installed. Another is after a swarm occurs. In all these cases, the number of bees may not be sufficient to withstand the beetles, allowing their numbers to reach a critical point, from which they can overwhelm the hive.
Adding too much space – by adding additional honey boxes – is also a potential problem. In this situation the beetles have the opportunity to find locations well away from the active colony, expanding their numbers without attention from bees.
Detecting Small Hive Beetle
In small numbers, SHB may not be easy to detect. Aside from relatively few to spot, they are quick to move and dislike light. There is a reasonable chance that they have hurried out of eyesight when you gracefully and calmly open your hive (as you should, of course!).
One way to check for SHB during an inspection is as follows:
- Place the top cover upside down on the ground, in direct sunlight
- Place the uppermost box on the top cover while you conduct the rest of your inspection
- After a while, quickly lift the box from the top cover. If SHB are in evidence they will have moved to the dark areas at the bottom of the box and onto the top cover
Another sign of SHB is the presence of comb that is slimy, or honey fermenting and oozing from cells. Once this spreads it becomes the most obvious way to identify SHB, such as the mess in the hive, as illustrated in this video.
Dealing with Small Hive Beetle
Prevention
As with everything in beekeeping, prevention is better than cure. The importance of a strong, healthy colony can’t be overstated.
Hives in bright sunlight are less likely to attract SHB. Ensuring there is not too much space in the hive is also important, so don’t add boxes before the bees are ready to fill with honey. Also, avoid the use of worn, warped or cracked hive components, which offer SHB the cracks and crevices they need.
Invective Nematodes
The tendency for larvae to fall under the hive is something the beekeeper can use to his/her advantage. The larvae will normally pupate in the soil, as we have seen. You can stop this cycle in its tracks by “booby-trapping” the soil with invective nematodes (Steinernematidae & Heterorhabditidae genera).
When the larvae burrow into the soil, the nematodes burrow into the larvae and vomit stomach bacteria into the larvae’s body cavity (delightful thought, eh?). These bacteria will turn the insides of the larvae into an icky rotten goo in just two days. The nematodes eat the goo and lay eggs.
The cycle begins again and very quickly (the nematode cycle, from infecting the larvae to new nematodes emerging, takes only 48 hours) the small hive beetles are no longer a problem.
Mechanical Traps
For use in the hive, various mechanical traps are available. They are often designed to result in the drowning of the beetles. Some of the more popular ones are called the Hood, West, Freeman, and Sony-Mel traps and the creatively named AJ’s Beetle Eater.
As an example, here is a video that illustrates how to install the Freeman trap.
Chemically
For those so inclined, chemical treatments are an option. The use of chemical treatments in beehives is strictly regulated and, in many states, CheckMite+ is the only approved chemical. The active ingredient in CheckMite+ is an organophosphate called coumaphos. Because this is toxic to both bees and humans, CheckMite+ should be used with great care.
More Resources
Here is a video that shows the larvae of SHB.
