Small Hive Beetle FAQ
As of 2017 NB is unfortunately no longer free of small hive beetle (SHB). All beekeepers should be on the lookout for this pest. Read up on the SHB so you know how to recognise them and what to do.
What is a SHB and why are they a problem?
Small hive beetles (SHB) are just what their name says - small beetles that like to live in beehives. If they kept to themselves they would not be a problem, but unfortunately they don't - they can pose a serious threat to honey bee colonies. The larvae of the SHB eat honey bee brood, pollen and bee bread stores, as well as wax and honey. They can reproduce rapidly, and in large numbers can devastate a of honey bee colony. Honey bees have a limited ability to control SHB. When SHB infestations grow beyond a certain point the bees may abscond or abandon the hive.
Where do they come from?
SHB (scientific name Aethina tumida), are native to sub-Saharan Africa. In their native range they are considered a minor pest of honey bee colonies, probably as the bees used in many managed colonies in Africa (Apis mellifera scutellata) are adapted to the SHB and have evolved behaviours that allow them to co-exist. It is also possible that the SHB in its natural range is restricted by other environmental factors and pathogens. Like many species of plants and animals, when SHB are introduced to locations where they are not native, they may take advantage of new and sometimes unforeseen sources of food or habitat, and be more successful than in their native range, as their natural predators are absent.
In the past 20 or so years, SHB have been spread to numerous parts of the world where they are not native, including locations in Europe, North and South America, and Australia. They have been spread in shipments of bees, as well as by other unknown means. In several cases they were first seen in port cities which suggests they entered by ship, possibly in shipments of goods such as fruit.
Are SHB in Canada?
Yes, since 2002 SHB have shown up in parts of Alberta, Manitoba, Ontario and Quebec. In 2017 SHB were also found in New Brunswick.
What is the SHB life cycle?
In areas where SHB are established they emerge from the ground, where the larvae pupate in small cells constructed in the soil. Adult beetles are good fliers, and like many insects, are very sensitive to chemical odours in the air. After emergence they seek out honey bee colonies (probably by homing in on odour signals). Although the bees recognise the beetles as intruders, they have great difficulty in either killing or evicting them. The SHB can withdraw its head and legs in the manner of a turtle. It has a smooth convex back that the bees cannot sting or bite through. When in its defensive posture there is little the bees can do to harm a SHB.
The bees will herd or corral SHB to corners or narrow crevices and attempt to keep them there. Sometimes they will partially propolise them into 'beetle prisons'. Despite this imprisonment the SHB survive by tricking the bees into feeding them by stimulating the bees' mandibles with their antennae. They can survive in this manner for at least 6 months. The SHB continuously look for opportunities to break out and lay eggs. Eggs can be laid in cracks, and can also be 'injected' beneath cell cappings by the long ovipositor of the SHB and laid directly in brood cells. These eggs are hidden and are not cleaned out by house bees. A single female SHB can lay from 1000-2000 eggs. When the eggs hatch after 3-5 days the SHB larvae proceed to eat their way through developing bee brood. They may spend from 15-30 days feeding, burrowing horizontally and affecting multiple cells of brood and stores. As they do this they spread a type of yeast that causes the honey to ferment into a slimy mess.
Mature larvae do not appear to be efficiently removed from the colony by the bees. They eventually crawl out of the hive and burrow into the surrounding soil where they pupate and begin the cycle over again. One life cycle usually takes about 6 weeks. Almost anywhere bees are kept has a long enough summer to allow the SHB to complete several breeding cycles.
While strong colonies seem able to keep the beetles somewhat under control, weak colonies can be quickly overwhelmed by SHB reproduction and the impacts of the feeding larvae. Such colonies then collapse and/or abscond.
SHB can persist in cold climates by living within bee colonies. Unfortunately, our cold winters will not kill them.
What do I do if I find SHB in one of my hives?
If possible collect the beetle(s) or larvae for positive identification. Preserve them in a vial or small jar of rubbing alcohol, windshield washer fluid, methyl hydrate or white vinegar. Beetles can also be killed by freezing them in a sealed ziploc bag. Do not send live beetles by mail. Report suspected SHB finds to the provincial apiarist and your local beekeeping organisation.
NB Provincial Apiarist:
Integrated Pest Management Specialist (Entomologist) and Provincial Apiarist / Crop Sector Development /
New Brunswick Department of Agriculture, Aquaculture and Fisheries / Hugh John Flemming Complex / 1350 Regent Street / P.O. Box 6000 / Fredericton, NB, E3C 2G6
Tel. (506) 453-3477
Fax (506) 453-7978
What controls are there for SHB?
There is no quick fix solution to eradicate SHB once they are established. However there are a number of measures that can be taken that may help reduce the impacts.
Keep your colonies strong. Combine weak colonies. Strong colonies can prevent runaway infestations.
Site hives in full sunshine. This helps the bees keep active longer each day and puts the SHB at a disadvantage.
Take extra care if feeding pollen patties. SHB are strongly attracted to these and may feed and reproduce in them.
Extract honey supers immediately on removal from the hive. If SHB are suspected, freeze the frames for 48h before or after extraction. Maintain all bee equipment storage areas free of old combs or debris. SHB will invade and reproduce very rapidly in unoccupied frames of honey.
Monitor your colonies carefully or SHB during normal inspections. Look for running beetles on the top frames when first opening the hive. Check brood areas for SHB larval infestation. Minimise colony disturbance during inspections.
If you find SHB, consider installing some beetle traps. There are various on the market or you can make your own, many ideas for trap designs may be found on line (see references below). Various kinds of duster cloths (such as Swiffers) have been found effective at trapping SHB, which have hooks on their feet. They become entangled and trapped in the duster sheets and can then be removed and killed.
Some beekeepers report success with metal baffles installed between the base of the bottom hive body and the hive base, coated with a water-repelling coating (trade name “Never Wet”). Beetles cannot get a grip on the metal and fail to enter the hive. Information on making these is available on youtube.
To date there are no effective chemical controls for SHB that are not either hazardous to honey bees or accumulative in beeswax. One possible exception is soil-dwelling nematodes that feed on insect larvae. These can be watered into the soil beneath hives where they may destroy any pupating SHB larvae. Experience with this approach is limited in Canada so far.
What is happening in other countries where SHB has been introduced?
First reports of SHB in the USA came from Florida and South Carolina in 1996-1998. Since then SHB has spread steadily and is now found in more than 35 states, including Hawaii. Northern states where SHB is found include Minnesota, Maine and Michigan. Since its initial arrival SHB has been extensively spread by migratory beekeeping operations.
SHB was first seen in New South Wales in 2002 and has since spread to many other populated areas of the country, including the states of Queensland, Victoria, and South Australia.
The first detection of SHB in Europe was in Portugal in 2004 in a shipment of bees from the USA. The bees were rapidly traced and all affected colonies destroyed. This prompt action paid off. SHB has not been observed since in Portugal, and is considered eradicated there.
After that, SHB was absent in Europe until 2014 when it was detected in southern Italy. Extensive control measures have been put in place in an attempt to prevent further spread and if possible eradicate the SHB. This includes the establishment of protection (20km) and surveillance zones (100km). Hives within 20 km of infected colonies in the protection zone are destroyed, as well as infected hives in the surveillance zone. The movement of hives is prohibited in the protection zone.
The EU has mandated that no hive products be exported from the affected region. These actions have had some success, and after initially spreading to the island of Sicily, SHB has since been eradicated there. Despite this, the SHB remains established in southern Italy and it is uncertain whether efforts to eradicate it will succeed. However it is worth noting that despite its existence for three years in a mild climate zone, the SHB has spread a shorter distance in Italy than it has in NB in a single season.
What is the outlook for SHB in New Brunswick?
Details of the spread of SHB in NB may be found on the GNB web site here.
In June 2017 the SHB was found in one location in northeastern NB. By September 2017 it had spread approximately 200 km to 11 communities in northern, eastern, central and southeastern NB.
In the absence of stringent control zones or concerted efforts to eradicate the SHB it is likely to keep spreading. Apiaries close to colonies that are seasonally migrated to locations where SHB has already been found are at greatest risk of early infection. Migratory beekeeping is thought to have been largely responsible for the spread of SHB in the USA and the same will undoubtedly apply in NB.
It is not possible to say at this stage how serious a pest SHB may prove to be in New Brunswick. Although the SHB may overwinter in honey bee colonies, it appears to pose the most serious threat in warm climates, where it may complete more life cycles per year, freely pupate and survive in the soil, as well as subsist on fruit in areas where there are few bee colonies.
References and further reading/watching
A good general factsheet on the SHB with high quality images, from Jamie Ellis' lab at the U of Florida.
Mar 2015 article in Bee Culture by Master Beekeeper Charles Linder. Presents a beekeeper's perspective on dealing with SHB in Illinois.
Very good thorough information on SHB from Jon Zawislak, University of Arkansas, Division of Agriculture. Has a very good graphic on the SHB life cycle as well as advice on control measures.
A very nice, clearly written and presented summary of SHB ecology by Oregon State University.
Thorough reference article by Dr Michael Hood, Clemson University, South Carolina. Lots of detail on control methods.
Presentation on measures taken to control SHB in Italy.
Detailed technical document on all aspects of SHB behaviour and control measures. Produced in the context of the situation in Italy, but also of general interest and containing a lot of information.
In-depth video presentation on SHB by Dr Jamie Ellis, University of Florida, one of the most knowledgeable authorities on SHB.
Image of SHB back and front
By James D. Ellis, University of Florida © Bugwood.org, CC BY 3.0 us, https://commons.wikimedia.org/w/index.php?curid=8634681
SHB larva head close up with black background: Sam Droege, USGS Bee Monitoring and Inventory Lab, Beltsville MD
SHB larvae on comb
By James D. Ellis, University of Florida © Bugwood.org, CC BY 3.0 us, https://commons.wikimedia.org/w/index.php?curid=8634554
SHB and bees on comb face
By James D. Ellis, University of Florida © Bugwood.org, CC BY 3.0 us, https://commons.wikimedia.org/w/index.php?curid=8634531
SHB with bees, closer image
Larvae tight in cells
By Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services - This image is Image Number 1265060 at Insect Images, a source for entomological images operated by The Bugwood Network at the University of Georgia and the USDA Forest Service., Public Domain, https://commons.wikimedia.org/w/index.php?curid=8634482
Prepared January 2018 by Rob Hughes, CBA Board member.
Left: Spot the beetles?
Right: Closer in - there they are. SHB are significantly smaller than bees.