Asian Hornets

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http://wild-life-in-france.blogspot.com/2013/10/asian-hornet-nest-in-stone-barn-wall.html
Asian Hornet nest in a stone barn wall.

Just when I thought things would go quiet on the "bee and wasp" front I received a phone call first thing this morning from a lady with an Asian Hornet nest in a cavity in a stone barn wall.

Due to the awful weather in most of France for the first 6 months of 2013 all "wasp" family species have had a bad year with a reduced number of successful colonies and a late start for those that finally got going.

This one had grown rapidly in the last 5 or 6 weeks, outgrown whatever space they had inside the wall leading to a requirement to expand the nest outside of the wall. Still very active, continuing to grow and at head height from the ground the nest was becoming a danger to the householder, her dogs and horses. Of course this is also one of those cases with an introduced species where destruction is a necessity especially if there is a likelihood of next years Queens being killed and reducing the number of colonies next year.Always sad to have to destroy such a beautiful creation and kill the occupants.

Information about the Asian Hornet can be found at Asian Hornet in France

Asian Hornets

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http://www.nonnativespecies.org/factsheet/factsheet.cfm?speciesId=3826
Asian Hornet, Vespa velutina

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Overview

Slightly smaller than native hornets; queens up to 30mm, workers up to 25mm.  Distinctive: thorax velvety black/dark brown; abdominal segments brown with fine yellow band, only the fourth segment almost entirely yellow-orange. Legs brown with yellow ends; head black with orange-yellow face.

Presence of Asian hornet was first confirmed in UK in September 2016 and there has also been isolated records in 2017, 2018 and 2019, all nests have been eradicated to date.

Habitat summary: Vespa velutina, Asian Hornet

Mainly in areas with deciduous trees where nests are built; sometimes in or around buildings where these provide suitable nest sites.

Overview table

Environment:Terrestrial
Species status:Non-Native
Native range:China, Indian Subcontinent, Indo-China, Malesia
Functional type:Predator
Status in England:Non-Native
Status in Scotland:Non-Native
Status in Wales:Non-Native
Location of first record:Tetbury, Gloucestershire
Date of first record:20

Origin

The area bordered by Northern India and China, as well as the Indo-Chinese peninsula and Indonesian archipelago. Individuals of the sub-species nigrithorax, introduced into France, are presumed to be from China. The climate of their native range in continental Asia is similar to that of Southern Europe.

First Record

Tetbury, Gloucestershire in September 2016.

Pathway and Method

Unknown.

Species Status

First recorded in France in 2005 and thought to have arrived in a container of pottery from China before 2004 through the port of Bordeaux. It has since spread rapidly throughout neighbouring départements. Breeding was also confirmed in northern Spain in 2010 and Belgium in 2011. Recorded from the Channel Isles in the summer 2016. First record in GB was received in September 2016.

Dispersal Mechanisms

Local dispersal by flight (which can lead to long-distance (national-scale) dispersal in a few years); long-distance dispersal is also human-assisted e.g. accidental with imports.

Reproduction

The egg-laying period is variable as the activity of fertile females depends on temperature and adequate feeding of the queen. Therefore, although queens may start laying some eggs in February, founding of nests may be later. In sub-tropical Asia colonies are not perennial; new queens over-winter alone or in small groups in cavities. In France it is unlikely that nests will contain living colonies during the winter; queens that have successfully over-wintered leave their shelters in spring to found a nest elsewhere. However, during the warm, damp winter of 2006/7, while single over-wintering queens were found in cavities in France, the nests remained occupied by workers until at least December. One queen creates only one colony per year.

Known Predators/Herbivores

In Aquitaine, France during the pre-winter decline of the colony, green woodpeckers, jays and tits were seen pillaging nests and eating the remaining larvae. It is unclear what, if any, other predators target Asian hornets.

Resistant Stages

Active nests can be difficult to find, despite their often large size, as they can remain hidden until autumnal leaf fall.

Habitat Occupied in GB

In France, this species nests in tall trees in urban and rural areas, avoiding conifer stands. Nests have also been found in garages, sheds, under decking, and rarely in holes in walls or in the ground.

Isolated records from Gloucestershire (2016) and Somerset (2016), Devon (2017), Lancashire (2018), Cornwall (2018), Hull (2018), Hampshire (2018), Surrey(2018), Kent(2018) and Hampshire (2019).

Environmental Impact

Predator of social wasps and other bees, including honeybees, and also consumes a wide variety of other insect and spider prey. So far, predation of honeybees in France appears limited to adults rather than the juveniles. Observers in France noted that the hornet hovers over the entrance to a beehive at a distance of 30–40 cm, then tries to catch foragers, primarily those returning with nectar or pollen. The hornets charge them from below and force them to the ground before paralysing and carrying them away. Each hornet only consumes a portion of the prey itself, the remainder being pulped for use as larval food. The hornets make numerous attempts to access beehives, especially late in the season (September to December) when the production of new queens makes high demands on hornet workers.

In Kashmir and China, Asian hornets are considered a major predator of honeybees with reports that it can destroy up to 30% of a colony of the Asian honey bee Apis cerana, although specific details are difficult to find. Hornet workers attack honeybee guards one by one before robbing their brood nest to feed their own larvae.

Later in the season they are particularly attracted to ripe fruit. Overall, their diet depends on what is locally available, the state of the colony’s development and competition from other predators. As for honeybees, hornets require sugars (energy for the adults) and proteins (nourishment of the brood).

Health and Scoial Impact

Social impact through damage to honeybee colonies.

Potential health impact through stings; although painful, Asian hornets are not considered especially aggressive, although care needs to be taken to avoid close proximity to nests which may be more problematic if nests are in or around buildings. Multiple stings may cause more serious health problems such as severe isolated arterial hypotension and ongoing neuralgia in the region of the stings.

Economic Impact

Losses of commercial (large- or small-scale) honeybee products. Possible costs due to replacement of damaged colonies. Costs, including time, associated with searching for, and destroying, queens and nests.

Identification

Roberts, S., Rome, Q. & Villemant, C. (2010) Information Sheet 12: Asian Hornet (Vespa velutina).

Biology, ecology, spread, vectors

Lombardero, X. (2010) La llegada del avispón asiático pone en alerta a los apicultores gallegos. La Voz de Galicia28112010 [accessed 20042011].

Management and impact

de Haro, L., Labadie, M., Chanseau, P., Cabot, C., Blanc-Brisset, I. & Penouil, F. (2010) Medical consequences of the Asian black hornet (Vespa velutina) invasion in Southwestern France. Toxicon 55:650-652

General

http://www.nationalbeeunit.com/index.cfm?sectionid=117

Mollet, T. & de la Torre, C. (2006) Vespa velutina – The Asian Hornet. Bulletin Technique Apicole, 33(4), 203–208. Available online in a translation by P. Todd for the Sept 2007 edition of Bee Craft [accessed 20042011].

Roberts, S., Rome, Q. & Villemant, C. (2010) Information Sheet 12: Asian Hornet (Vespa velutina).

Gallery: Asian Hornet



Asian Hornets

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http://www.planetepassion.eu/wildlife-in-france/asian-hornet_vespa-velutina-nigrithorax_frelon%20asiatique_france.html
Asian Hornet - Vespa velutina nigrithorax - Frelon asiatique - France

First observed in 2005 the Asian Hornet is thought to have arrived in France from China in 2004, in a container of pottery passing through the port of Bordeaux. Since that date its spread throughout the neighboring regions has been rapid and often, in the initial stages, follows rivers and other watercourses. In fact it will never be found far from a source of water even if that is only a small pond. As of 2011 there are reports of them being observed in Belgium and they are to be found in strong pockets in the north of France, the expansion is relentless.

Photo Above - Asian Hornet Queen attracted by honey in early April following hibernation. 

The nest is built using “paper mâché” made from chewed tree and plant material. It is composed of several wafers of cells surrounded by a double skinned envelope of broad reinforced paper scales, striated with beige and brown. Unlike the European Hornet where the entrance is on or near the bottom, the entrances are on the sides, (see photo). Another difference is that the European hornet makes its nest in cavities, whereas the Asian Hornet makes a suspended nest, usually in a tree but sometimes in a large open roof space. This is easy to see; it is spherical or oval and can be as much as 1 metre in height, 80cm in diameter and generally between 4 and 15 metres from the ground. It is rare for it to use a hollow in a tree or cavity although it can happen. Unfortunately the nest is sometimes hidden by the trees foliage and as its comings and goings are more discrete than the European hornet their presence isn’t always noticed until the leaves begin to fall in early autumn. 

Photos above: Queen Asian Hornet constructing her initial nest. 

Although the European Hornet will attack and kill the odd honey bee in small numbers as a food source for their larvae it does not present a problem, however the situation is far worse with the Asian Hornet and can possibly lead to the destruction of the entire colony. The Asian Hornets will station themselves hovering at about 30cm from the entrance to the honey bee colony where they pounce on returning bees, often those that are carrying pollen, fall to the ground with them or fly a short distance to land on something and cut off the head with their mandibles. Here they remove the wings and legs before making a little “meat ball” that they transport back to their nest to feed their own larvae. Having found a colony, often a bee hive, they will sometimes arrive in numbers to take an easy food source one after another. The consequences for the bee colony could be catastrophic if the flow of pollen into the hive is severely disrupted. Over time it could result in the death of some or all of the larvae and the queen could either stop or reduce her egg production. This will lead to the decline of the colony, aging bees will die with few or no replacements to take their place. At best the colony will be vulnerable to disease due to the dead larvae and the overall weakness of the colony could lead to robbing. The colony will have a much reduced hope of over wintering. However there is increasing evidence that they are taking other insects as a source of protein to feed their larvae and even behaving more like the European Hornets and native wasps in taking meat including carrion. 

Photo immediately below of Asian Hornets on a dead Blackbird and beneath that on a dead mouse.

Above: Asian Hornet killing a honey bee

Photos above: Asian hornets nest suspended in a tree showing the entrance slits. 

Photo above shows Asian Hornets and Honey bees feeding together on wax and honey in late October. At this time the Asian hornets will not kill the bees because they have stopped producing eggs and there are no larvae to feed, although they will rob weak bee colonies of their honey stores if given the opportunity although Hornet protection grills can be fitted to hives if required or the hive entrance reduced by other means. 

Photo above: Asian Hornets feeding on honey and wax. 

Photo: Asian Hornets nest inside a stone wall in France.

See.  http://wild-life-in-france.blogspot.fr/2013/10/asian-hornet-nest-in-stone-barn-wall.html

Photo. Asian Hornets nest in an empty bee hive, Vienne, France

See ASIAN HORNETS NEST IN AN EMPTY HIVE

Scale of risks for honey bees: 

It's increasingly unclear just what the scale of threat is to Honey bees and it's possibly been overstated. There is no question about the fact that they do prey on bees at the colony entrance but it's likely that there would need to be a very large Asian Hornet colony in very close proximity to a bee colony to cause serious harm especially if there were a number of bee colonies together spreading the load. It could be that the risk is greater in the south of France with a longer season for the Hornet colony to get started and grow in size.

Photo below is an Asian Horents nest in my apiary 2014, not visible until the leaves fell in November. 

See.  ASIAN HORNET NEST IN MY APIARY

Risk to humans from this species is minimal except when and if they consider their nest to be under threat, otherwise they are more timid than the European Hornet and their sting is no worse than that from an ordinary wasp.

They are only out during daylight hours unlike the European Hornet that will also fly at night.

As with all the social wasps (common Wasps, Hornets and Polistes), the colonies of the Asian Hornet live only one year and it is only fertilised queens survive the winter in hibernation.

Solutions:

Small nests with only a queen at the beginning of the season, (as in the photos at the top), can be destroyed using a powerful aerosol wasp spray with caution. 

Larger nests should be destroyed as a matter of urgency by a competent person that is equipped for the job.  As the destruction of their nests and the laws surrounding it is a constantly changing situation you should check with your Mairie but the current situation is that there is a legal obligation on the property owner to have nests destroyed. 

In early spring try to kill as many Queens as possible. They will be easily lured to the scent of honey and I find swatting them with a plastic tennis racket is the easiest method. 

Please don't use traps as they will also attract and kill our native species of Hornet and Social Wasps which are already suffering enough and in decline.

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