BBKA ASIAN CONFERENCE 6TH MARCH 2021

Summary Notes of Morning Sessions

SESSION ONE: THE BIOLOGY OF THE ASIAN HORNET BY PROFESSOR STEPHEN MARTIN

Key: AH = Asian Hornet/s

The biology of AH and the honey bee is very diferent. In AH, new queens are mated in the autumn as the colony is dying out, then go into hibernation. In spring, the queens emerge, feed on pollen and tree resin and build a starter nest out of paper. Over the next month the nest will slowly enlarge. After a couple of months there’s a small group of ofspring. The queen now stays in the nest laying eggs, while the workers do the rest. Nest grows and will be at its maximum in the autumn. Nest usually dies out with the frst frosts. As the colony dwindles it produces a batch of hundreds to thousands virgin queens and males. They mate, the males die, and the mated queens overwinter. AH don’t store honey and are carnivorous. They are at their most vulnerable in March and hibernate in places that are dry and cold eg under roof of beehive, old caravans, out- buildings, under tarpaulins. The queen folds her wings under the abdomen. Once she breaks that position she can’t re-enter hibernation.

When new queen emerges in April, her frst job is to fnd food, as she has no fat body now so food is vital. She builds an ‘embryo’ (very small) nest. Can fnd these in bird boxes, cavities etc. Lays about half a dozen cells which are very vulnerable to predators like ants. Nest size goes from golf ball to tennis ball. Once it reaches small football size, the colony relocates the nest. About 100+ workers at this stage. Embryo nest is outgrowing the space it was started in, so nest relocates. Scouts choose new location, usually high up in trees. They run two nests for a time (new nest and embryo nest) then queen moves to the new nest. AH is only one of three hornet species that can relocate nest. New nest can really expand in size. They don’t always move, depends where frst nest was started. They like clear and easy access to nests, so high in trees or even clif faces.

Key time for colony is July, August and September, when there’s rapid expansion. This is when majority of nests have been spotted as they are large and obvious. Cross-section of nest will reveal about 7-8,000 cells arranged in concentric circles. Late September time, frst frosts, colonies disappear. But can linger on in nests if there is food, so if access to honey bees then nests can be prolonged. Nests can expand to 2m+ tall. Some photos where colony had access to extra food the nest was almost size of adult human. Predating honey bees prolongs size of nest. Comparing the diferent sexes of the AH: queen, worker and male all look similar and same size, so not easy to distinguish. Males have slightly longer antennae and marginally squared of abdomen. If open up and fnd white fat bodies, these are the new queens.

AH arrived in Korea in 2003, and spread well. 100,000 nests recorded, 15,000 injuries and 10 deaths/yr, mainly urban areas. AH will concede food to larger , so may explain its move into urban areas. Another problem, in Japan, noticed there is cross-breeding of native hornet queens with AH males. Tactic to get rid of other species. No native hornet sperm found in AH queens.

AH afects pollination of wild plants as it is removing the pollinators. It has natural predators but they don’t impact much.

Moku (RNA) virus detected in AH from Jersey, France and Belgium. Very common in European yellow-jackets, sometimes seen in honey bees.

AH v good at preying on honey bees, which account for 38% of AH food, with 20% social wasps, 30% fies. Needs 11kg of per AH nest. (asian honey bee) has tactics to deal with AH eg use waves or ball hornet. European honey bee not yet adapted to AH.

Giant Asian Hornet (media termed “murder hornet”) established in forests around Vancouver. Huge hornet which does mass attacks on honey bee colonies to get brood and honey. Takes heads of. Apis cerana uses dung on entrance against mass attacks. Hornets don’t like it and leave alone. If beekeeper reduces entrance, hornets will just chew their way in. But bees are clever, will also ball hornet and heat it to death. Will take some time for mellifera to learn this. Global suitability mapping for Giant Asian Hornet includes Europe, it would do well in the UK.

Q&A key points:

Tree resin provides source of carbohydrate. Temp inside nest ~32c. AH gives of solution, can use to heat muscles to maintain temp. Ants don’t pose a threat as AH uses ant repellant so ant can’t leave a trail for other ants to follow. As long as AH has sufcient food it will survive. Their ‘northern limit’ is increasing. Native hornet is now in Yorkshire. When AH queen emerges in spring, v placid at this time. Easy to bag up. She defends embryo nest against other queens; queen fghting over usurping, so some natural regulation of population this way. Eg in NZ, paid children to collect single wasp queens in spring, then had the best year for wasps ever! Probably due to lack of usurpation queen deaths.

Just a matter of time until AH established in UK, then we will have lost control of it. Each nest needs 11kg of food, and it will go for easiest food source. Apis cerana is not easy, but mellifera is. It’s another invasive threat, minor compared to climate change and pesticides, but another stressor.

Mating occurs outside nest probably above forest canopy, queens don’t return. Queens get fat bodies, mate, leave, hibernate. To avoid in-breeding, males diferentiate using pheromones so don’t unite with queens from own nest. Also emerge a few days apart so reduces chances of in breeding. Drones die after mating.

2020 a quiet year, maybe due to COVID, less travel. Most brought over in caravans etc.

AH travels shortest distance for food, laziest option. Once fnd hive of bees, like an open supermarket.

Should really call AH the yellow-legged hornet, to distinguish from giant Asian hornet.

AH tends to hunt early mornings and late evenings when prey is torpid. Will take prey from spider’s nests.

In Europe AH got access to European honey bees so can produce more queens than in Asia.

AH is a multiple-mated species (mates with several males) so good variety of genes. Honey bees can do a recalibration ie shufe their genes to get rid of in-breeding. Colonies in France probably only came from 1-2 AH queens. So have genetic mechanisms for getting round these problems.

Best way to interrupt life-cycle of AH - destroying the nests. No point trying to collect queens as about 99% die anyway, natural selection. Once nests are relocated and become established, they become visible - this is the time to remove them. If you remove 95% of all nests, only reduce AH population by 50% as they can bounce back. Very hard to locate nests.

SESSION TWO: THE FRENCH EXPERIENCE BY ANDREW DURHAM, CAMBRIDGE BKA

The best hope of stopping the AH is the Asian Hornet Team.

Situation in France: they have the equivalent of our BBKA, BKA’s, NBU and individual beekeepers.

AH nest densities vary tremendously across France. What factors afect numbers? Cote D’Or - AH been there about 10 years. It disappeared, then reappeared in 2016. Similar to Pas de Calais. The primary spread of AH has been along the major rivers. In more mountainous areas eg Massif Central, very small established numbers. There is an association with rivers and canals. AH likes to nest near water and urban areas. Urban reporting bias, rural nests under-reported?

In 2018, early warm spring, lovely warm summer - AH nests quadrupled. Where get early warm spring then frosts, reduces nests. Weather is major factor in year-on-year numbers. AH follows scent to fnd its prey; honey, pollen, nasonov glands. As areas are warming up, so nest numbers increase. AH is adaptable and climate is changing to its advantage. Physical geography afects spread; high ground, fewer nests.

AH efect on French beekeepers: education on AH is vital for beekeepers. Reported that colonies declined by 20-30%. In 2017, French senate committee concluded biggest threats to honey bees were: pathogens and pesticides, loss of forage, climate change and pests (including AH). Top pest is varroa. All efects cumulative. Winter mortality rates for 2017/18 - 30% loss nationally. Some areas over 40%. Near Paris 49%. Four main reasons for mortality: weather; agriculture; beekeeping practices; varroa. AH didn’t get a mention but could be straw that breaks the camel’s back.

Honey production fgures for France: 1995 - 35,000 tonnes, 2015 - 17,000, 2017 - 20,000, 2018 - 28,000.

For a good 15 years now, forage in France is over by July, whereas before it went on for another few weeks. Due to climate change.

Initial response in France to AH: no strategy as belief that no risk to public health. Beekeepers’ reports of colony losses dismissed as anecdotal. Also belief that AH would become self-limiting. AH has had quite an impact in France eg on wine-production, hedge-cutting, farmers. In recent years AH nests have come down from the trees to lower down, almost 70% are now below 5m. Average nest has ~1,200 workers, largest nests >2,000. Nests now found behind shutters, meter cupboards, wood piles, roofs, buildings. People are stung without provocation. AH can spit a painful venom into eyes (freman fell of ladder after being spat at). Within 5m of nest any disturbance can provoke mass attack.

Due to lack government action, French public started their own campaign against AH, eg fring paintballs of pesticides into nests. In Spain nests are blown up. Costs 200-300 euros to get nests destroyed, so nests go unreported, and AH allowed to spread. At end of 2012, French government changed its position and reclassifed AH as category 2 pest and therefore the responsibility of beekeepers. In Lorien region, free of charge destruction of nests, Best they can do to stabilise the situation. Conclusion: don’t wait to see how hard AH will get as you can’t go back. Need collective action to control or slow down proliferation of AH. More info available through BBKA speaker list.

SESSION THREE: SITUATION IN UK BY NIGEL SEMMENCE, NBU

Yellow-legged Asian hornet update: Native to Asia, came into France 2004 at rate of about 80km/yr, but there are ‘hops’. SW France estimates of >10 nests/km sq.

Very visible when you get AH nest near your colonies, will see ~3-10 hornets hawking bees.

Defra has rolling newspaper corrections to correct photos of AH. NNSS: quite small but big impact. Includes BWARS. NBU: 50 bee inspectors, 8 regional bee inspectors.

NBU leafets and new info coming about making AH monitoring traps more easily, will be two videos. They do talks for BKA’s and also have info leafets for Association AH teams. New for 2021: breakdown of sightings and nests. Beebase has AH page, and info on AHAT (AH action teams) format. If see AH embryo nests, can bag up at night and destroy (freezer). AH build up nests by adding layers to outside and chewing away inner layers. On small nests entrance is at bottom, on larger nests entrance is on the side. Nests aren’t always in trees, can be in bird boxes etc. Native hornet (V. Crabro) nest is very diferent; open at bottom where debris drops out.

What can beekeepers do?

• Set up AHAT’s (Asian Hornet Action Teams) • Use ID guide and poster from Beebase • Buy AH in acrylic from Thornes Key thing: educate members and the public. Be aware.

DO NOT approach nests, report it!

NBU uses AHAT’s to follow up local leads.

Spend time looking for hornets in your apiary. Use monitoring rather than killing traps (Vita Pharma trap has been improved). If suspected sighting in apiary, record on Beebase. Report any suspect sighting, with photo. Can catch AH in net then put in freezer. BBKA has an AH tab, using postcode.

How should report?

1. Use AH app - best method to prevent mis-identifcation. 2. Online NNSS. 3. Alert email (although discourage this as v time-consuming).

CEH involved - they developed the App.

Beecraft article August 2020 on AH.

In 2020 there were 9,592 reported sightings, of which two confrmed. Much confusion with other species; , giant wood wasp, hornet mimic hover fy, wasps. NBU has special licence to deal with AH, using FiconD until Sept 2021, then will switch to another insecticide. Not all nests high up, the one in Gosport was in apple tree 20ft up. Bee inspectors are key workers under Covid. NBU has improved guidance, simplifed making monitoring traps and bait stations. AH Track and Trace App coming out shortly. Speeds up identifying AH for bee inspectors.

Conclusion: for all years in UK, 21 confrmed sightings; 10 nests destroyed, which came from 8 queens. Nests were from ground level to 20ft high. All nests been small, about 30cm across. DNA showed all had come from European incursions. They had not yet produced queens but some had produced males. No evidence of an established population yet in UK. So still in eradication phase for 2021.

Key points: AH can occur anywhere in UK. Unobtrusive in environment, likes urban or semi-urban environments. Nests have to build up in size to be visible. Most fying hornets seen foraging within 1km of nest. Use fsh for bait. Be aware of primary and secondary nests. AH likes feeding on fallen fruit and on the insects there. Don’t yet have Giant AH here. AH interact with European hornets at feed stations, found European hornet nest within 10m of AH nest. Do not release any AH you have captured, to track it. Only NBU can do this.

SHORT VIDEO SHOWING AH HAWKING BEEHIVE

The more AH predating, the fewer honey bees can forage, so foraging and therefore food income drops signifcantly. The more AH there are predating at hive entrance, the more workers required to defend the hive, means more foragers caught by AH at blocked entrance. AH only try and catch bees coming back to the nest, so returning bees try to come back fast into entrance.