Changeling Varroa

Newly-Emerged Bee With Varroa Mites (The Brown Discs)
Newly-Emerged Bee With Varroa Mites (Brown Discs)

At the Leiston and District Beekeepers’ Association AGM, some exciting new research into varroa mites was disclosed. (The L&DBKA partly sponsors an Eastern Area Research Student (EARS) project and that student is associated with this research).

These new insights into the fiendish cunning of these deadly bee parasites showed that varroa mites employ chemical camouflage to move, undetected, from the bee, on which they feed, into the brood cells, where they reproduce. Since the odour of a bee is very distinct from the odour in the brood cell, this is quite a transition.

Essentially, a varroa mite can change its chemical profile in between 3 and 9 hours when switching between bee or brood cell hosts and thus remain undetected by the bees. Even a dead varroa mite is capable of mimicking its host’s odour.

Here is the Abstract from The Journal of Chemical Ecology: Social insect colonies provide a stable and safe environment for their members. Despite colonies being heavily guarded, parasites have evolved numerous strategies to invade and inhabit these hostile places. Two such strategies are (true) chemical mimicry via biosynthesis of host odor, and chemical camouflage, in which compounds are acquired from the host. The ectoparasitic mite Varroa destructor feeds on hemolymph of its honey bee host, Apis mellifera. The mite’s odor closely resembles that of its host, which allows V. destructor to remain undetected as it lives on the adult host during its phoretic phase and while reproducing on the honeybee brood. During the mite life cycle, it switches between host adults and brood, which requires it to adjust its profile to mimic the very different odors of honey bee brood and adults. In a series of transfer experiments, using bee adults and pupae, we tested whether V. destructor changes its profile by synthesizing compounds or by using chemical camouflage. We show that V. destructor required direct access to host cuticle to mimic its odor, and that it was unable to synthesize host-specific compounds itself. The mite was able to mimic host odor, even when dead, indicating a passive physico-chemical mechanism of the parasite cuticle. The chemical profile of V. destructor was adjusted within 3 to 9 h after switching hosts, demonstrating that passive camouflage is a highly efficient, fast and flexible way for the mite to adapt to a new host profile when moving between different host life stages or colonies.

That’s just not cricket !

The Poly Hive

This is a little experiment. Penny Robertson, Secretary of my local Leiston and District Beekeeping Association in Suffolk, told me in 2014 that she was not aware of any of the LDBKA’s  >100 members using, or ever having used, a poly hive. So I installed this one last summer and this is what I saw last weekend – with the thermometer showing a chilly 4C !

With the bees flying at these low temperatures (note that 10C is generally viewed as the lowest safe temperature for bees to fly) it is possible to offer both positive and negative interpretations about Castle hive’s unusual excursions. Here’s how:

An Optimist might rejoice that the bees are so well insulated in their poly-hive that they are able to fly in unusually low temperatures. A Pessimist might respond that this could equally be a function of their breeding line, rather than their lodgings, a classic case of nature, rather than nurture. Furthermore, he might add, there is no obvious advantage to be flying in dangerously low temperatures, so perhaps something about their the poly hive is forcing them to fly. Perhaps they need water to dilute their honey stores, or the fondant and pollen feed which I can see them eating on top of the frames. Ah-ha, replies the Optimist – that suggests that they are benefitting from an early build-up of brood, which will position them well for the Spring – unlike the draughty Snape and Iken cedar hives. Then again, perhaps the bees in the traditional wooden hives are regulating their hives so that some natural condensation is retained inside for diluting their stores to make them edible for brood-raising, so they do not have to fly, counters the Pessimist. Hmmm.

So will I be enthusiastically recommending the use of polystyrene hives to the good beekeepers of the Suffolk coast in 2015 ? Too early to tell.

But while the jury’s out, here are some other considerations about using the poly hive. The Pessimist would note that, as configured, it has bottom bee-space, so the semi-rigid transparent plastic sheet supplied as the roof to seal the hive, makes it fussy to close up the hive, jiggling the sheet around to avoid squashing bees between the plastic roof and the frames. Also, the walls of the hive are too wide to attach a frame holder, which are very useful to keep a couple of frames pressed up close to the outer wall of the hive at inspection time, rather than putting them on the ground, leaning against the hive. The Optimist would strike a more positive note, pointing out that the hive floor has a nice sloped landing board, that the polystyrene body makes the hive lightweight to handle, and that all the poly infrastructure can be intermixed with wooden brood and super boxes, if required. And finally, it is easy to strap down to a paving slab to keep it from blowing away in the wild coastal winds.

So it will be a while before I can assess the outcome the first year of my Suffolk poly hive. And when I’ve made my mind up, I’ll take the Optimist and the Pessimist down to the Jolly Sailor to buy them both a pint of Adnams bitter.

Dancing In The Dark

Cuban-Dance-2

At the LDKA apiary last Saturday (no, that’s not us at the apiary in the picture – more about that later!), the highlight of “going through” the hives with our tutor Penny Robertson, was seeing two foragers performing vigorous “waggle-dances” on the brood comb. As we watched this energetic ballet, a distant memory popped into my mind…

In 1999, I went on a charity-bike ride to Cuba. One night, in the (aptly-named, in my opinion) city of Colón in Matanzas, I was walking back to the team hotel in the pitch dark, thanks to a power-cut. As I stepped slowly past the large, arched, peeling windows of a row of Spanish colonial houses, I heard a muffled footfall and caught sight of a movement in the shadows inside one of the buildings.

I halted, as much apprehensive as inquisitive, and glimpsed through the open window a sight which was quite breath-taking – a family of four, two adults and two teenagers – dancing with silken elegance in the silent shadows….as if the music of their heartbeats, the welling of an unremembered rhythm, had risen like a tide and flooded their senses – so they danced anyway, through the dark, pin-drop silence of the power-cut.

Which brings us back to the bees’ “waggle-dance”: likewise a muted cha-cha, performed at home in total obscurity and with the participation of close family. Let me describe it to you, before suggesting a link which shows the “waggle-dance” and has a David Attenborough voice-over:  the “waggle-dance” is a hushed communication, with one bee dancing, at antenna’s length, from the circle of bees around her, like a lasses-only version of the Scottish reel “Dashing White Sergeant”, but performed without the lights on ! But over to that nice Mr. Attenborough for some visuals of:

The Waggle Dance

So the purpose of the “waggle-dance” is for the dancer to communicate the direction and distance from the hive of food sources.  Just like our own dances, the “waggle-dance” is conducted on a specific patch of comb. The returning forager dances to convey information about the nectar or pollen source which they have just visited by waggling their abdomens and moving on the comb, for the benefit of a small group of available foragers, who touch her with their antennae to gather information from her movements.

Looking at a bee “waggling” on the comb, the human brain understandably attempts to assign meaning in the optical plane. Close, but no cigar! Remember, in the bee-world inside the hive, all is dark, so visual communication is null and void. The actual meaning in the “waggle-dance” display is pulsed through vibration, as the dancer grips the comb and the signals resonate to her rapt audience. With the comb hanging downwards, as it does in nature, in its “waggle-dance” the bee encodes, relative to gravity, the distance and direction of the food source. The other bees absorb this pulsating intelligence, but by the time they are ready to fly from the hive to the feeding-zone, the instructions have been miraculously de-ciphered into a flight manual based on the orientation of their hive to the sun, specifically at that time of day. Amazing and accurate.

You may be one of the few fortunate souls on god’s green earth who has not been button-holed recently by a beekeeper complaining about how depressingly poor the last couple of years have been for bees. But in any case, you are probably aware of the severe pressure on bee-populations, of the trials and tribulations of the craft of beekeeping. But please take away from this monograph that, however tough it has seemed, there are still rewarding moments to be extracted, jewels of appreciation to be mined with a hive-tool – including the simple waggle of a single bee !

ps: For those wishing to delve deeper into the mysteries of the “waggle-dance” (and why foraging bees switch off their colour vision when flying back returning to their hive) I can recommend Jürgen Tautz’s “The Buzz About Bees – Biology Of A  Superorganism”.

pps: And for those who wish to see a drone “waggle-dancing”, (clue: plenty of noise, lights, music and purely recreational) – there’s always “Dancing In The Dark” by Bruce Springsteen in 1984.

BLink: Neonics – Listen To The Fruit !

Carmen Miranda

Whenever a telephone marketer calls me, I decline to engage in conversation and ask them instead to send me the details of their offering by post. That generally does the trick, but even if they comply with my request, I can then assess their proposal at leisure in my own good time.

Similarly, as a matter of principle, I ignore any “e-petition” sent to me, including the many I have received from all sides on neonicotinoids.

When two strident voices are contradicting each other, as in the neonics debate, it can be refreshing to hear a “still, small voice of calm” from a genuinely interested party at the very centre of the debate. So I was delighted to receive via John Symes (a committee member of my beekeeping Association, the LDBKA) this well-balanced update on events as seen through the optic of fruit growers – take a bow “Eurofruit” – founded in 1973 as “the international marketing magazine for fresh produce buyers in Europe”. So this is what the remarkably sane world of fruit cultivation had to say about neonicotinoid developments to date:

http://www.fruitnet.com/eurofruit/article/158173/ec-to-ban-three-neonicotinoids

I was also transfixed and vaguely alarmed to discover from the same august publication that: “The European Commission’s decision to lower the MRL of DPA could lower topfruit exports, according to experts”. But I will leave the e-petitions on the merits or otherwise of the lowering the MRL of DPA and the impact on our topfruits to somebody else…and I will await with fortitude my next telesales cold-call.

In life, as in beekeeping, “Don’t allow yourself to be put under pressure” is a decent maxim.