Tag Archives: asian hornet

2017 in retrospect

The end of the year is a good time to look back at the highs and lows of the season. What worked … what didn’t work … what on earth happened to our weather in June?

Early June 2017 ...

Early June 2017 …

June is an important month here in Fife. Early season colony buildup should be pretty much complete, most colonies will have had some sort of swarm control measures in late May, virgin queens may well be present in many hives, the OSR is over and colonies need to consolidate for the main summer flows.

But instead it just rained.

Rainfall in Fife was 225% the 40 year average, access to apiaries was problematic due to flooding and queens could only get out to mate if they were wearing ‘water wings‘.

Big mistake

Many colonies needed to be, or should have been fed, during June. Mine had reasonable levels of stores as I’d not taken much early season honey. I therefore chose not to feed them. In retrospect I think this was a big mistake.

Although not monitored carefully, I suspect brood rearing slowed, so reducing the colony size to effectively exploit the July/August flows. It was my worst summer honey crop in years.

Lesson one … If this happens next season I’ll continuously feed thin syrup to keep the queen laying strongly.

Doing the splits

Notwithstanding the incessant rain, swarm control – and the inevitable associated queen mating – went pretty well. I generally use splits of one form or another and most queens got out to mate, albeit a little slower than I’d have liked. If swarm control is needed for colonies in the bee shed we can’t do vertical splits (because of the way entrances are organised) and instead just take a nucleus colony away and let them rear a new queen.

Only ‘pretty well’ though because I suspect I lost a cast from a vertical split that went calamitously wrong. I’d left the queenless half far too strong and inadvertently also left multiple developing queen cells.


This wasn’t going to end well  🙁

I did manage to capture and hive another cast from the same colony, but the first virgin queen and well over half the workers were long gone.

So, lesson two (which I’ve been taught many times before 😥 ) is to be decisive when there are multiple queen cells in a split. Either knock them back appropriately (which I’ll explain next year) or split the box up into multiple nucs. Don’t dither. Don’t prevaricate and don’t – as I think I did this year – simply forget to check.

All the gear, some idea

I blatantly poached how to build foundationless frames with bamboo skewers from the internet. I claim zero originality here. It isn’t my idea. However, I’m pleased to say it was a great success. Simple wooden starter strips were also a roaring success. It’s very satisfying when you realise you don’t need to spend £1 per frame on foundation.

Nearly completed ...

Nearly completed …

I’ve used quite a few Abelo poly hives this season. They’re a strident colour – blue and yellow – but reasonably well made. Colonies checked this winter are doing well in them, with bees right up to the side walls on sub-zero days. This suggests to me that they are well insulated.

An Abelo/Swienty hybrid hive ...

An Abelo/Swienty hybrid hive …

There are some aspects of these hives I have yet to be fully convinced by; upper entrances, the crownboard, high condensation levels and a small Varroa tray. I’ll review them more fully when I’ve been using them for at least a full year.

Old invasives …

The bête noire of most beekeepers, the Varroa mite, has featured heavily throughout the year. In print, though thankfully not in my colonies. I’ve tried to emphasise the need to treat appropriately, using the right miticide at the right time. Since most approved (and even some unapproved 😉 ) miticides are all pretty effective, the timing of treatment is probably the most important point.

2016 temperature data and OA treatment ...

2016 temperature data and OA treatment …

In three recent posts I presented the importance of midwinter treatment, how to prepare the oxalic acid-containing miticide and how to administer it. These should probably be read in conjunction with an earlier article on when to treat, which I’ll come back to in a minute. Finally, as far as Varroa is concerned, I discussed potential ways to optimise the timing of the winter treatment by watching the weather. I suspect that most beekeepers treat too late in the winter.

If you have yet to treat this winter … get a move on!

… and new ones

The new invasive that got some coverage was, inevitably, the Asian hornet. Having first arrived in 2016 I think we’ll be subjected to annual incursions until it gets established here. Constant vigilance is going to be needed to help postpone what might be inevitable. Just because it is inevitable doesn’t mean we shouldn’t try and delay it’s permanent arrival.

Devon beekeepers got some first-hand experience of how vigilant you need to be to both spot and photograph Asian hornets in September. Martin Hocking has written about his experience in the Devon Beekeeper (pp172 and also in November’s Bee Craft)  which should be required reading for beekeepers, with a follow up article about his experience in December (see pp196). There’s an open meeting on the 20th of January at Harberton Parish Hall, TQ9 7SD where the threat posed by the Asian hornet – and how to mitigate it – will be discussed.

Although rarely mentioned this year, Small Hive Beetle now appears to be established in the Calabria region of Southern Italy. Data updated in late September and November indicates that positive wild colonies and sentinel nucleus colonies are still being found, indicating that attempts to eradicate the beetle have failed. Infested colony numbers are perhaps a bit lower than previous years, but since there’s no readily-available data on the level of surveillance, it’s not clear whether this shows that control is having an effect, or if people are just not looking as hard.


Posts have been made every Friday of the year, with a few additional ones when something important happened (Asian hornets or I was ‘advertising’ a Convention I was speaking at … OK, my talk wasn’t important, but the Welsh Beekeepers Convention was 😉 ).

Regular as clockwork ...

Regular as clockwork …

The Friday posts are intentional. It’s when most of us have time to read stuff. The regularity was not and, frankly, it’s a bit of a surprise I’ve achieved it. However, there it is. No promises it’ll continue like that. You can register to receive email notification of new posts in the right hand panel.

Visitor numbers to the site are markedly increased from last year. Page views per visit are down fractionally, but not significantly. It’s clear that more are finding the site as it becomes better indexed by the search engines, and as pages are referenced by other sites.

24 months on www.theapiarist.org ...

24 months on www.theapiarist.org …

My attempts at generating a presence on Facebook was an abject failure. I simply don’t have time to do anything other than automagically post updates from here on Facebook (as I do on Twitter, which I’m a bit more familiar and competent with … follow me on @The_Apiarist). Apologies if you tried to ‘Friend’ me (or whatever) on Facebook. I’ve cancelled all the email updates as I simply couldn’t keep up. Or, when I tried, I didn’t know how to! I belong to the pre-FB generation, or the one before that.

Beekeeping is international, with different problems – but many shared ones – globally. I’m grateful to the visitors from 161 different countries and the European Union 🙂 Less than 50% of the readers are from the UK, despite the UK-centric bias I inevitably exhibit (°C, colour, no mention of queen castles or slatted racks, precious little discussion of Langstroth hives etc.). Southern hemisphere beekeepers don’t even do things at the same time of the year, so many of the posts aren’t even topical for readers in Australia, New Zealand and South America. Whatever, I’m grateful people took the time to visit and read stuff.

And the winner is …

I don’t publish visitor numbers, but I do comment on the popularity of particular pages. For several years a post on my honey warming cabinet has been the most popular. It was originally posted ‘way back’ in 2014. Frankly, it was useful, but not particularly challenging or exciting.

But it’s all change this year. Aside from the homepage, the archive and blog pages, all of which people arrive at to to get the most recent posts, the honey warming cabinet post was a distant fourth in the 2017 rankings.

Above it were posts on vertical splits and making increase, feeding fondant and – particularly pleasingly and top this year – when to treat colonies with miticides against Varroa. I say particularly pleasingly as the When to treat? post is a serious article on an important subject, underpinned by scientific arguments. The timing of the late summer treatment is probably one of the most important events in influencing the health and overwintering success of the colony. This post was almost twice as popular as any other post this year which – because it originally appeared in early 2016 – suggests it is finally being widely cited and accessed by beekeepers.

When to treat?

When to treat? Finally getting read when it should be.

And what does the future offer?

Frankly, as I write this in mid-December with a streaming cold, a box of tissues and slathered in Vicks VapoRub (really, it’s not a pretty sight) I don’t know. I have two priorities at the moment; getting the new bee shed properly setup and (with my researcher hat and lab coat on)  starting studies of Chronic Bee Paralysis Virus. Both will get coverage here.

Bee Shed 2 ... the windows still need some work.

Bee Shed 2 … the windows still need some work …

In terms of the website I’m acutely aware there’s no proper indexing or rational list of articles on particular subjects, perhaps other than Varroa. I hope to bring some order to the chaos, allowing me to not repeat myself, to develop some themes more fully and to not repeat myself 😉 . I also know I have a load of unwritten stuff on queen rearing.

Winter time is also DIY time … dabbling with wood, perspex, Correx and Elastoplasts. Something will surely result from this, in addition to the blood loss and bad language.

If there are things you’d particularly like to read drop me a note. I’m interested in the science underlying beekeeping and have little patience with some of the dogma and That’s the way we’ve always done it stories. I’ve already written about the importance of training and the responsibilities of beekeepers. I’ve got some more on these areas planned as I think they’re too often ignored by beekeepers in the UK.

With Best Wishes for 2018. May your colonies be docile, your supers unliftable, your queens well-mated and your swarms (again) in my bait hives 😉

Happy New Year



Extrapolating Asian Hornets

Extrapolation in mathematical terms means “the extension of a graph, curve, or range of values by inferring unknown values from trends in the known data”. There’s a rather poor scientific joke which involves ‘extrapolating the line’ from a single data point.

Here’s the same joke from the incomparable xkcd.com

Extrapolating (with thanks to xkcd.com)

… which brings us neatly to the Asian hornet (Vespa velutina). This invasive species predates honey bees and other pollinators and is a threat to beekeeping for two reasons:

  • by killing honey bees (which comprise > 50% of the diet) it can destroy colonies
  • by hunting at hive entrances it prevents bees from foraging, so reducing honey yields
Vespa velutina

Vespa velutina …

As many will be aware, at those who members of a beekeeping association or internet-savvy, an Asian hornet nest was discovered in Tetbury, near Bristol, in September 2016. Although the nest was destroyed (and other nests were not found) there remains the concern that the Asian hornet may be established here. If that’s the case, or if when it arrives again, how far and how fast will it spread in the UK?

A recent publication by Matt Keeling and colleagues has attempted to to address this. You’ll appreciate the relevance of the cartoon above … August 2016, no hornet nests, September 2016, one hornet nest. How many can we expect in the future?

A long way from home

Asian hornet distribution ...

Asian hornet distribution …

Unsurprisingly (the clue is in the name) the Asian hornet comes from Asia. The native distribution includes tropical South East Asia where it exists in a number of different colour morphs or sub-species. However, it spreads – naturally on its own and with the inadvertent help of man – and is now established in Korea, Japan and North West Europe.

The Asian Hornet appeared in South West France in 2004. It was thought that overwintering queens were imported with a shipment of pottery from China (it is the V. velutina nigrithorax subspecies – see map for native distribution). Since 2004 the Asian hornet has spread widely across France, Spain, Belgium, Portugal and Italy. You can view a dynamic Google map showing location and time of detection here.

It’s a short hop across the Channel from Northern France for an insect that flies strongly and disperses widely, so there was every expectation that the Asian hornet would appear in the UK in due course. Remember that bluetongue virus of sheep was introduced to the UK in 2006 by tiny Culicoides midges wafted across the Channel on the prevailing South Easterly winds.

Brexit or not, the Asian hornet can easily get to Southern England.

Closer to home

Asian hornets were first found in Tetbury, Gloucestershire, in September 2016 and subsequently in North Somerset. A nest was found in Tetbury and destroyed. Haplotype analysis demonstrated that, unsurprisingly, the hornets were related to those in Northern France. Worryingly, this analysis also demonstrated that the hornets were related, but no closer than at the grandparent level.

This suggests one of two scenarios. Either there were two separate incursions from France by hornets that were closely related or the Asian hornet was established in the UK before 2016 and the Somerset and Gloucestershire finds represent progeny (two generations later) of this initial invasion.

There have been no further reported Asian hornet finds on the mainland (as of early August 2017 and remembering that absence of evidence doesn’t mean evidence of absence) though additional nests have been found on Jersey and it’s possible that the hornet is established in the Channel Islands.

How far, how fast?

Whether or not the Tetbury hornet incursion has been contained there remains the question about how far and fast will the Asian hornet spread in the UK.

This is the sort of thing that can be modelled by epidemiologists. Taking account of a variety of factors such as the numbers of queens produced per nest, the environmental suitability for the hornet, the dispersal distances and – importantly for a species originating in tropical regions – the latitude (and hence temperature).

Much of the real numbers for these various factors come from studies of the spread of the Asian hornet in France. For example, the mean dispersal distance of new queens is about 18 miles i.e. Tetbury to central London in about 5 generations.

Predicted spread of the Asian hornet in UK …

In the figure above A-D are the early years (<5), E and F are the predictions for 10 and 20 years hence. Remember, this is an inexact science as the predictions are being made from a very small founder population. G shows the confidence limits which, at 90% (the palest shading) are very broad.

Is Scotland safe?

As a beekeeper in Scotland the potential to spread North is a concern … those of you living further South can simply jump ahead to the conclusions.

A key feature of the prediction Keeling and colleagues made was that increasing latitudes (and possibly altitude going by the pale shading of North Wales and the Pennines, though this could also be lack of suitable nesting environments – the Asian hornet prefers oak trees apparently) will restrict breeding success and hence spread due to reduced temperatures.

They modelled this by assuming reproductive success/spread (actually queens/nest) was 100% in Andernos-les-Bains, France (where much of the data used for the modelling was derived) and 0% in the North of England. This mirrors the situation for the European hornet which is much less common in Northern England. Assuming a linear decrease in queens per nest over this distance they reproductive success in Tetbury is only 38% that in Andernos-les-Bains. 

With these assumptions, Scotland is safe. I should add that I’m talking about natural distribution and spread. A single Asian hornet was discovered at a “retail warehouse in the central belt of Scotland” in March 2017. Although there’s no further official news about this discovery it seems likely it was imported ‘on the back of a lorry’ (and the SASA/NBU people will be able to tell where from after genetic analysis) to one of the giant distribution warehouses in Motherwell or Livingston. If the assumptions made about reproductive success at increasing latitudes are correct, this type of introduction is unlikely to result in the Asian hornet getting established in Scotland.

All of the modelling discussed so far assumes no intervention by FERA or by protective and vigilant beekeepers. The impact of nest destruction will be discussed in the future … but don’t get your hopes up 😉


Asian hornet nest

Asian hornet nest …

With only one (or two?) incursions and no further reports in 2017 it’s possible that the Asian hornet is yet to become established in mainland UK. Once here – and I think it’s pretty certain it will get here and become established – the speed with which it spreads may look like the model proposed here. If the underlying assumptions on reproductive success, dispersal distance etc. are representative of the situation in the UK then – without effective intervention – we can expect it to be widespread within a couple of decades.

However, a feature of all epidemiological modelling is that they are subject to revision and reinterpretation … inevitably leading to further publications.


STOP PRESS and related …

Asian hornet isolation confirmed in Woolacombe, North Devon, late September 2017

Full analysis of 2016 isolates published in PLoS One. Budge GE, Hodgetts J, Jones EP, Ostojá-Starzewski JC, Hall J, Tomkies V, et al. (2017) The invasion, provenance and diversity of Vespa velutina Lepeletier (Hymenoptera: Vespidae) in Great Britain. PLoS ONE 12: e0185172. https://doi.org/10.1371/journal.pone.0185172

† Don’t mistake the Asian or Yellow-legged hornet (Vespa velutina) with the Asian giant hornet (Vespa bloodyenormousandterrifying). The latter has a wingspan of 7.5cm and its proper scientific name is Vespa mandarinia. A number of newspaper articles in autumn 2016 made this mistake. Many also chose to use images of the European hornet (Vespa crabro) or other large stingy-looking insects … none of which are likely to help the public correctly identify the invasive Asian hornet.

Vespa mandarinia

Vespa mandarinia …

Asian hornet in the UK

The National Bee Unit has confirmed the discovery and identification of an Asian hornet in Tetbury, Gloucestershire. The press release has further details.

Asian hornet

Asian hornet …

These hornets are smaller and darker than the European hornet. Note in particular how dark the abdomen is, with only the fourth segment predominantly yellow (in contrast with our European hornet where at least half of the abdomen is yellow). The National Bee Unit has a very useful guide to identifying the Asian hornet (Vespa velutina) and distinguishing it from the European hornet (Vespa crabro).

Inevitably there’s going to be a lot of statements about “the end of beekeeping as we know it” and speculation of the impact it will really have on our colonies. Time will tell whether it’s been identified early enough to eradicate, how it arrived in deepest Gloucestershire and where it came from.

The Asian hornet has been established and spread widely in France since inadvertent importation in 2004 from China. It was discovered in the Channel Islands earlier this summer. It’s arrival on the mainland was expected, but is nevertheless disappointing.