Blog – bees, beekeeping & other sticky subjects
Pollen-rich diets help combat varroa
We have known that honey bees use plant resins with antibiotic properties to control pathogens in the colony, but a multi-national team of researchers has just shown that pollen-rich foods help too.
In investigating this “social immunity”, they tested to see if pollen is beneficial for honey bees infested with the parasitic mite Varroa destructor which is associated with deformed wing virus (DMV).
First, they studied the effects of pollen on the survival of infested bees in the laboratory and in the field. They observed that a pollen-rich diet can compensate the negative effects of mites. They went on to identify the beneficial pollen compounds.
Under lab conditions, pollen did not have much effect on bees without varroa, but it did lengthen the lives of those infested by the mite. In the field, although the sample size was small, the effect was more dramatic with all of the control colonies dying out while two pollen-fed colonies survived.
The researchers think that it is the lipidic compounds of pollen that have a positive effect – but they don’t rule out other compounds. They even think that bees may be deliberately selective in their foraging to get the right balance of macronutrients.
The full research report published in Nature online can be read here.
The research gives further support to the field trials showing the beneficial effects of VitaFeed Nutri pollen supplement.
Asian hornet predictions in the UK
With the ability to spread at the rate of 70-80 km per year, what are the prospects if the Asian hornet (Vespa velutina) takes hold in the UK?
The first Asian hornet nest was discovered and destroyed in the UK last year, so researchers have tried to predict its spread in Britain if it can establish itself. Their work is inevitably hypothetical, but it has been based on the eight-year experience of events since the arrival of the hornet in France.
Prevention of the spread of the Asia hornet is a pressing concern because in France its diet consists about 50% of Apis mellifera, with other valuable pollinators contributing to the rest.
The researchers set about creating a mathematical model to try to predict the track of the potential invasion. They made some assumptions: the average distance for a queen to fly to set up a new nest is 28 km, but fortunately it is not expected to do well as it travels north and they have tentatively expected it not to establish itself at all in northern England. They have even managed to factor in eradication attempts.
After 10 years, the invasion could be widespread with more than 50,000 nests with as many as five nests in each km2 in certain areas. After 2o years, an area’s carrying capacity is expected to have been reached.
Uncontrolled expansion will be disastrous say the researchers, so detection and eradication is vital. They think that limited local searching would result in a a finite – and often short – time until control efforts fail. New incursions are likely to increase over time as the hornet becomes further established in mainland Europe.
In France, only 48% of nests have been detected and this is not enough to control an invasion, say the researchers. Nonetheless, valuable lessons can be learned from the French experience.
The year 2017 is thought to be critical to the immediate future – if more nests are found, the prospects are not good, but if none are discovered this will be reassuring giving the possibility that the south of England is not a conducive environment for the hornet.
The full paper can be read here.
Meantime, Vita suggests putting its Apishield Asian hornet traps in place to monitor – and to protect.
IMYB DCA Hunt
Did the International Meeting of Young Beekeepers find a drone congregation area (DCA)?
Video coming soon.
Woodborough Hill, sometimes known as Treasure Island, in the Vale of Pewsey is a mysterious place! Twenty-five years ago, a group of midnight UFO spotters were terrified when they reported a craft “80-100 feet (30m) wide”. They flashed at it – it flashed back! Two years later, another group heard what they interpreted as the sound of a ghostly hunt – hunting horn sounds and all!
Well, they did indeed find a DCA. It was still at first and the queen pheromone lure on the end of a fishing rod was attracting nothing. But then a breeze sprang up – and the noise of drones was clearly to be heard, though nothing could be seen!
With eyes looking skyward, they appeared – not huge numbers, but very convincing.
The drones even chased small objects thinking they were queens on the wing.
Keep watching this url for more photos and the video currently being edited!
What Rev Gilbert White heard?
UPDATE: This story and audio featured on Paddy O’Connell’s Slow Radio feature on BBC Radio 4 on 25 June 2017. You can listen here, starting at 41 mins 8 sec in.
On 28 June 1792 – 225 years ago – the Rev Gilbert White, a pioneering English naturalist living in Selborne, Hampshire, England, heard a mysterious sound which he documented:
Humming in the Air
There is a natural occurrence to be met with upon the highest part of our down in hot summer days, which always amuses me much, without giving me any satisfaction with respect to the cause of it; and that is a loud audible humming of bees in the air, though not one insect is to be seen. This sound is to be heard distinctly the whole common through, from the Moneydells, to Mr White’s avenue-gate. Any person would suppose that a large swarm of bees was in motion, & playing about over his head. This noise was heard last week on June 28th.
From The Natural History of Selborne by Rev Gilbert White.
Gilbert White did not know what it was, but we now realise that it was almost certainly the sound of a drone congregation area (DCA) – where male honeybees go to mate on the wing with queens. No-one can satisfactorily define the characteristics of these special areas, but they can persist year after year – and seemingly century after century.
Today, 225 years later, Sheep Down on Selborne Common is still a drone congregation area.
This week, armed with a queen pheromone lure, we recorded the sound that Gilbert White might have heard:
And below is a video of drones flashing about Sheep Down in search of queens (unfortunately interrupted by the audio of a passing airplane!). Those little flashing specks are drones caught in the late afternoon sun.
Without the queen pheromone lure, it’s unlikely that you’ll hear the sound so clearly today unless there are queens in the vicinity. How, then, did Gilbert White hear it so well? Perhaps there were many more honey bees in his day? There are many orchards in the area, so, with orchards, you should find pollinating bees. Perhaps, like us, he heard it on a very fine day.
Looking back through what sparse weather records exist, it doesn’t seem to have been a good summer, but that 28 June 1792 might have been an unusually good day.
1792: “A wet summer (in London).”
24 June: “Thunder, & hail. A sad midsumr day.”
21 June: “Longest day: a cold, harsh solstice!”
May & June: “cold and dry”.
July “wet and cold”
28 June 1792: “Glow-worms abound on Baker’s hill (Selborne).”
Glow worms: “muggy nights from June to August usually see more activity than cool ones”.
So, perhaps it was a rather special day when lots of cooped-up drones and queens came out to play!
For more about DCAs on this blog, start here.
Vita’s Guest Beekeeper Blogger
Varroa in the UK: 25 years on
In April 1992, the varroa mite was discovered in the UK for the first time. By May 1992, the talk of varroa was on every beekeeper’s lips.
Dr Max Watkins, now Technical Director of Vita (Europe) Ltd, but then working as technical and commercial manager with Sandoz, recalls:
‘The news travelled rapidly that varroa had been seen in Devon. It had been spreading across Europe where Sandoz was supplying the acaracide, Apistan, but I hadn’t been expecting varroa quite so soon in the UK. However, I knew that the first identification of the mite was bound to lag its actual arrival by quite some time.’
Dr Watkin’s suspicions were soon confirmed when, a little later that fateful spring, a semi-professional beekeeper in the Home Counties contacted him about suspicious mites in his colonies.
‘I visited the beekeeper and sure enough it was varroa – lots of them, even though the bees didn’t look to be visibly suffering. In desperation, he had unsuccessfully tried a home-made miticide, but when he used Apistan the mite population very quickly came under control. He was very impressed!’
‘At that time, Apistan was not yet officially approved for use in the UK and we did our best to accelerate the registration. The pan-European approval procedures were not then in place and registration did not happen until 1997, partly because part-way through the legislation changed!
‘However, we managed to have approval just in time for the autumn 1997 National Honey Show. There was a lot of interest! Vita (Europe) Ltd had just started up in earnest after the management buy-out from Sandoz and we were already working on Apiguard.
‘Unfortunately, in the mid-1990s, a lot of old-school beekeepers didn’t want to admit that varroa was a real problem. Sadly, they were wrong and many of those older beekeepers lost their bees and ceased beekeeping. Since then, beekeepers have become far more vigilant about the general health of their honey bees.’