Blog – bees, beekeeping & other sticky subjects
Early signs of varroa
Turlough, Vita Bee Health’s Guest Blogger, writes:
On the first day this year that the bees were flying freely, I decided that it was time to do a varroa mite test. Two (centrally placed) colonies in an apiary of four had varroa screens and suddenly, after Christmas, the varroa drop on those trays looked ominously high. I didn’t expect to see any varroa but over a period of two weeks the weekly fall was in tens!
The reason for this unprecedented early season high drop rate is mysterious. The colonies appeared healthy and showed very little sign of varroa all last season. When treated with Apiguard in late summer, the varroa drop was surprisingly small. My best guess is that there was a late season invasion from bees fleeing one or more varroa-infested feral colonies in the area. Another apiary two miles away and treated in exactly the same way shows no such alarming signs of varroa.
Action was clearly needed. Three weeks ago, one colony was treated with Apistan, the other (a stroppy bunch that were due for uniting with a nicer colony later in the spring) was left untreated for the time being.
The test for the presence of the mite with Sweinty’s varroa tester is simple. Approximately 200 bees are collected in a special container (see photo). Using a CO2 ‘gun’, the container is filled with CO2 gas which stuns but does not kill the bees. It also seems to stun the varroa mites. While the bees are comatose, the container is shaken moderately and varroa clinging to the bees should fall through a metal mesh to be collected and counted in the bottom lid. When the bees are exposed to fresh air again, they revive and can be left on top of the frames to make their way back down into their hive again (see photos).
Today, the CO2 varroa tester results were illuminating.
The two colonies without varroa trays showed one varroa mite each. I have seen no figures of what is acceptable but this was not alarming.
The colony recently treated with Apistan showed one varroa mite, indicating that the treatment had been working well.
The untreated colony showed a drop of five varroa mites!
The untreated colony result was rather alarming — but expected. According to the suppliers of the tester, a drop of more than 15 mites in summer would indicate that the bees should be treated immediately. In a winter-sized colony in February just as breeding of both bees and varroa has begun, the figure seems alarmingly high. Apistan was immediately inserted in this colony.
In the USA, a widely accepted metric is that a drop of three or more varroa mites from 100 bees in an alcohol wash indicates that a colony is doomed. With my bees, that drop of five mites from about 200 bees suggests that the colony is teetering on the brink.
This apiary will be under very special observation this season.
Bee Gym update
Stuart Roweth, inventor of the Bee Gym, writes:
Trials have shown that adding a Bee Gym increases varroa mite-drop in the hive. The Bee Gym is a patented device to assist and improve grooming behaviour in honeybees to help them to control varroa mite populations.
The challenge for me as the inventor and developer has been to develop the Bee Gym methodology through experimentation and to increase its effect.
In 2018 the key questions seemed to be.
- Where is the best place for the Bee Gym?
- Which parts of the Bee Gym frame are most frequently visited?
- Does adding more Bee Gyms increase the effect?
Where is the best location for Bee Gym?
As the bees groom themselves and dislodge a varroa mite, it seems to make sense to place the frame as near to the mesh floor as possible, so that the mite falls out of the hive.
However, a counter-argument is that since the bees spend so much more of their time on the brood frames, especially in winter, why not place the Bee Gym on top of the brood frames where it’s warmer and more likely to be visited? Unfortunately, this means that mites knocked off one bee are free to jump onto another.
In March 2018, I inserted a Bee Gym on top of the brood frames in an untreated double nucleus hive (Hive PB1). Nothing much happened initially, but I noticed that after three months the mite fall was down to 0 or 1 per day. That in itself is not that remarkable as the colony might not be representative.
Closer inspection showed there was plenty of brood and eight months later this colony showed no significant varroa build-up, even though mites have been present throughout the season at low levels.
This was exciting because they are the kind of results I’ve been looking for during the six years of the Bee Gym project. On a personal level, it’s fantastic to see such healthy bees that seem to be sorting out their own parasites. They are the first to fly on mild days and always in greater numbers than the other hives.
I started looking at the condition of the Varroa mites that had come through onto the sticky board in Hive PB1. More than 50% had been damaged. Using a low-power microscope, you can see the damage: the mites have missing or severed limbs, damage which is known to be inflicted by bees. Observations like these might help answer the question of what happens once the mites are groomed off.
Which parts of the Bee Gym frame are most frequently visited?
Key to the Bee Gym design are the shaped pieces (flippers) attached to the plastic frame and the ways bees interact with them. Therefore, my next experiments tried to ascertain which of the flipper designs was the most effective.
Although Hive PB1 was a 12-frame colony, it was arranged as six frames on top of six in a polystyrene nucleus. I started thinking that its success might be due to the tall thin shape of the hive. One Bee Gym is just enough to cover the area on top of six brood frames.
Does adding more Bee Gyms increase the effect?
I have given many talks on the Bee Gym and a question that often comes up is: why not use more than one Bee Gym?
My thinking had been that there seems to be a voluntary element to the bees using the Bee Gym, so why would you need more than one if the bees are going to make their own way to the Gym?
I experimented with various configurations of Bee Gyms over the next few months. The results led me to try placing two or more Bee Gyms into a shallow eke (shallow upward hive extension) on top of the brood frames in the four strongest hives in the apiary. This has produced some very interesting results. (Since the Bee Gyms need a gap of only 16 mm, an alternative to an eke is to place the Bee Gyms on top of a framed queen excluder [bottom space hive] or under a framed queen excluder [top space hive]).
Although there were plenty of varroa mites around, none of these hives had the kind of build-up in mite-drop levels I’m used to seeing in untreated hives throughout previous autumn periods.
The hives are doing well and the coming spring will confirm whether or not these bees are controlling their own mite levels and whether low levels can be sustained during the 2019 season.
Aims and purpose of the Bee Gym Project
- Year-round varroa protection to produce healthy bees
- Chemical-free varroa control to create sustainable colonie
- Simple solution for beekeepers
Preparing healthy bees for world’s biggest managed pollination
The world’s largest managed pollination event is beginning. Demand for bees to pollinate California’s almond orchards is high and shows no signs of lessening. The area of almond orchards is growing but the availability of bees is declining because of bee disease.
Almonds are big business and the statistics are impressive. California produces about 80% of the world’s commercial almond crop. The 2018 harvest was forecast to be 2.3 billion pounds (more than 1 billion kgs) in weight and it grows year on year. Pollination costs are $400 per acre ($162 per hectare), although the beekeeper is likely to receive up to $200 per colony.
Bees are trucked in from many states to start their annual pollination tour of the country and the economic incentive to have bees ready for this early spring pollination is very high.
A curious way of overwintering bees is developing in California taking ideas from Idaho where bees have been stored over winter in cool, but not freezing, potato sheds.
Idaho produces lots of potatoes and much was stored in large excavated caverns below ground until sold. Since the Idaho winter temperatures can plummet to 20 F, anywhere a constant temperature in the low 40s F can be maintained is valuable. In the winter beekeepers stored their colonies in unused below ground space. Today, huge insulated storage buildings above ground that are temperature- and humidity- controlled have been built
At temperatures in the low 40s F, bees will not attempt to fly, therefore conserve energy and food stores, are less stressed and will have a better chance of emerging healthy and ready for spring pollination
In Bakersfield, California, near the almond orchards, they are learning from Idaho with new-style potato-shed overwintering, but beekeepers there are trying to cope with quite a different climate. Central Valley winter temperatures can fluctuate considerably (but mostly above freezing), so potato-shed style overwintering can lessen unproductive activity in winter warmth and help prepare the bees for the almond orchard pollination in February. There can be as many as 40,000 colonies stored in a temperature-controlled shed. Rental is about $20 per colony.
One bee farmer is renting out 15,000 colonies this year. It’s big business and healthy bees are key.
SHB – Why do bees lock ‘em up?
Some of the reactions of honey bee workers to the small hive beetle (SHB – Aethina tumida) are very curious. SHB is a serious pest of honey bees and, where the beetle is present, Apis mellifera beekeepers are having to learn how to help their bees cope with it.
Native to sub-Saharan Africa, SHB was first seen in North America in 1996, Australia in 2002, and in Europe – southern Italy – in 2015. Once established in an area, SHB has proved impossible to eradicate.
SHB invades colonies creating a disgusting mess of fermented honey, eggs and larvae. They roam the hive and the females will lay their eggs in cracks and crevices.
Jerry Hayes, of Vita Bee Health North America, has dealt with many SHB pest alerts and says the beetles are expert at selecting weak hives. “They seem to detect honey bee stress pheromones from miles away. They are a secondary predator taking advantage of honey bee colonies that have declining populations and are losing the ability to police themselves. Why are the colonies the weakening? It’s usually down poor varroa management. And the beetles keep attacking the weakest colonies”
Beekeepers can place a Beetle Blaster trap between frames in a brood box to act as a sentinel or as longer-term protection.
In sub-Saharan Africa, the African bee, Apis scutellata, will often simply abscond and start a new nest elsewhere leaving behind the horrible mess created by the pest. The western honey bee, Apis mellifera, is less likely to abscond.
If the bees don’t abscond, what then? Some curious habits have been observed. Workers have been seen feeding SHB – perhaps fooled by some pheromone emitted by SHB.
A more effective honey bee response has been to chase the beetles around the nest to herd them into corners where the beetles are then imprisoned behind a wall of propolis. But here is the very curious part: the bees don’t just leave them there to die; they often make small windows in the propolis jail walls through which they feed the beetles! The beetles cannot escape but they are fed. SHB seem to be able to trick some workers (but not all) into feeding them. No-one quite understands why.
Meantime, stingless bees (Trigona carbonaria) are more ruthless in their treatment of SHB. They coat invading beetles with a lethal mix of resin wax and mud. No further treatment is required!
See also: Robin Moritz and Robin Crewe, The Dark Side of the Hive, OUP, 2018.
Unexpected threat left by Hurricane Michael
Jerry Hayes of Vita Bee Health has stepped up to help beekeepers in the Florida Panhandle following the third most intense Atlantic hurricane ever. In October, an estimated 3000 honey bee colonies suffered the brunt of Hurricane Michael when it made landfall in the Florida Panhandle and blew its way north through the Carolinas. The main damage took a surprising form.
Although one commercial beekeeper reported losing 200 colonies mainly because the roofs came off in the hurricane leaving the colonies exposed to robbing, the danger for most beekeepers’ colonies was to be in the weeks following the hurricane.
Tony Hogg, president of the Florida Beekeepers Association, explained that physical damage was not the main problem. Many hives survived, but the damage to pollen and nectar sources was huge.
Assessing the situation and knowing the area well from his time as Florida’s chief apiary inspector, Jerry Hayes, Vita’s vice president in North America, said, “I quickly realised that the most effective way of helping beekeepers and bees to recover from the damage – and the potential colony losses to come – was to provide a range of feed products. Local forage had been decimated and will take months to recover. Meanwhile the bees will be without food – not just nectar, but even more importantly pollen to help the colonies build up and recover. By the beginning of December, I had arranged the distribution of sufficient VitaFeed Power, Vita BeeFood and VitaFeed Nutri to feed 1000 colonies.”
Grateful for the contribution, Tony Hogg told Jerry Hayes, “I would like to thank you and Vita Bee Health for your contribution to the recovery effort. It has been a challenge for all to make it come together but a worthwhile challenge. The contributions have made an impact as folks are getting bees back into shape.”