Varna, 3 August 2026, Monday, 16:07:46

HORNETS

This is not an instruction that should be read only when an invasive hornet is seen. It is an instruction that should already be known, because knowing and applying it may save lives.

The Giant Asian Hornet — the Aerial Predator That Can Turn an Apiary into a Battlefield

Some insects impress us with their beauty, others with the complexity of their society, while still others seem almost designed to test the resilience of everything around them. The giant Asian hornet belongs to all three groups. It is a magnificently adapted predator, an important part of nature within its native range, and at the same time one of the most serious potential threats to beekeeping wherever it is introduced outside its natural environment.

Its scientific name is Vespa mandarinia. In English-language literature, the name “northern giant hornet” is increasingly used. The sensational media nickname “murder hornet” may attract attention, but it prevents people from understanding the real problem. For a beekeeper, the danger is not that one monstrous insect flies around attacking everything alive. The danger lies in the organised activity of an entire predatory colony capable of locating, marking and destroying a honey bee colony.

The Largest Hornet in the World

The giant Asian hornet is the largest known member of the true hornets. Workers are usually about 35–40 millimetres long, while large females and queens may reach approximately 45–50 millimetres. The body is massive, the head is unusually broad and yellow-orange, and the thorax is dark brown to almost black. The abdomen has clearly visible dark and yellow-orange transverse bands. It is precisely the combination of a huge head, powerful jaws and a heavy body that distinguishes it from most European wasps and hornets.

Its jaws are not used only for gripping. The hornet uses them to cut and crush its prey. The sting is mainly a defensive weapon and is used when fighting larger opponents, while during attacks on honey bees the powerful mandibles usually play the decisive role.

Despite its frightening appearance, an individual hornet does not normally seek conflict with humans. The greatest risk arises when someone approaches a nest, traps or presses the insect, or attempts to destroy the colony without professional help. Official authorities emphasise that the species does not normally attack people unless it feels threatened, but multiple stings can be particularly dangerous.

Where It Lives

The natural range of Vespa mandarinia covers large parts of South and East Asia. Modern genetic and biogeographical studies trace it from Hokkaido and other parts of Japan westwards to northern India, and from the Russian Far East southwards to parts of China and Southeast Asia. Confirmed records are known from China, India, Bhutan, Japan, Korea, Laos, Malaysia, Myanmar, Nepal, Russia, Taiwan and Thailand.

This is not a typical insect of open, treeless plains. It prefers wooded areas, low mountains, forest edges and green spaces where old roots, decaying wood and abandoned underground tunnels are available. The nest is most often located in an underground cavity, such as an abandoned rodent burrow, around rotting roots, or in low tree cavities. Aerial nests are possible, but unusual.

In 2019, the species was discovered in British Columbia, Canada, and in Washington State, USA. American authorities found and destroyed four nests in 2020 and 2021, using traps, reports from members of the public and radio telemetry transmitters attached to captured live hornets. After three years without confirmed sightings, the United States authorities declared the species eradicated from the country in December 2024.

This is a rare example of the successful eradication of an invasive insect during the earliest stage of its introduction. The success demonstrates how decisive early detection, public participation, the tracking of individual insects and the destruction of nests before the emergence of newly fertilised queens can be.

An Important Distinction: Not Every “Asian Hornet” Is a Giant Hornet

Three different species are often confused in Europe:

Vespa mandarinia is the giant Asian hornet, also known as the northern giant hornet.

Vespa velutina is the Asian yellow-legged hornet — a smaller species that is already spreading through a number of European countries and represents an immediate invasive threat to European beekeeping.

Vespa orientalis is the Oriental hornet, which occurs naturally or has long been present in parts of Southeastern Europe, including the Balkans.

Therefore, a photograph of a large hornet in Bulgaria is not proof that Vespa mandarinia has appeared. European reports and control programmes are currently focused primarily on Vespa velutina, which has already been reported in many European countries. Official European and British sources explicitly warn that the two Asian species should not be confused.

The Life of the Colony

The cycle begins in spring, when a fertilised queen emerges from winter dormancy. At first, she is alone. She finds a suitable cavity, builds the first cells, lays eggs, hunts and feeds the larvae. After approximately forty workers emerge, the queen remains inside the nest, while the workers take over construction, defence and food collection.

Adult hornets mainly require carbohydrates and visit tree sap, fruit and other sweet food sources. The larvae, however, require protein. Workers therefore hunt beetles, caterpillars, praying mantises, spiders, other wasps, hornets and honey bees. The captured insect is dismembered, and suitable parts are taken back to the nest to feed the developing offspring.

Towards the end of summer, the colony reaches its greatest strength and begins to produce males and future queens. At that time, the demand for animal protein increases, and attacks on colonies of social insects become particularly intense. This is the most dangerous period for apiaries.

After mating, the young fertilised queens leave the nest and overwinter individually in soil, decaying wood or other protected places. The old queen, workers and males die. During the following spring, every surviving queen may establish a new colony.

How an Attack on a Hive Begins

The destruction of a honey bee colony does not begin with a mass attack. A scout usually appears first. It circles the landing board, captures individual bees and evaluates the strength and accessibility of the colony.

When the hive is identified as a suitable target, the hornet may leave a chemical mark that attracts other hornets. In this way, solitary hunting develops into an organised attack. Research and official programmes describe mass attacks mainly against honey bee and wasp colonies located relatively close to the hornets’ nest.

First Stage — Hunting at the Entrance

Individual hornets position themselves around the hive and intercept returning bees. This does more than reduce the number of foraging workers. The predator’s presence may disrupt the colony’s normal activity. The bees fly less, the incoming supply of nectar and pollen declines, and the colony gradually becomes exhausted.

Second Stage — Slaughter

During a mass attack, the hornets do not immediately attempt to carry away every bee they kill. They first destroy the defenders. Using their powerful jaws, they decapitate or tear apart the workers one after another. The attack may continue until the adult population of the hive has been killed or scattered.

American authorities state that under suitable conditions an entire honey bee colony may be destroyed within hours, and in some recorded cases in approximately an hour and a half.

Third Stage — Occupation

After overcoming the adult bees, the hornets begin guarding the entrance of the conquered hive. Their real targets are the brood, larvae and pupae — concentrated protein food for their own offspring. They carry parts of the honey bee brood back to their nest until the resource is exhausted.

It is precisely this sequence that makes Vespa mandarinia such a dangerous enemy. A single hornet kills a limited number of bees. An organised group, guided by a chemical signal and supported by a large colony, can destroy the entire hive.

Why the European Honey Bee Is Particularly Vulnerable

Within the giant hornet’s natural range, some Asian honey bees have evolved alongside it and possess specialised defensive responses. The Japanese honey bee, Apis cerana japonica, may allow a scout to approach the entrance, after which hundreds of bees surround it in a dense living ball.

The bees activate their flight muscles, raising the temperature and the concentration of carbon dioxide in the centre until the hornet dies. This behaviour is known as a “hot defensive bee ball”. It has been documented experimentally and is believed to be the result of prolonged co-evolution between predator and prey.

The European honey bee, Apis mellifera, does not possess such a well-organised and reliable defence against Vespa mandarinia. Individual bees attack, sting and gather around the entrance, but this resistance is often insufficient against the hornet’s armoured body and powerful jaws. Apiaries with many hives concentrated close together therefore represent a particularly attractive and easily exploited food source.

Importance for Beekeeping

The damage is not limited to the number of bees killed. The presence of large hornets around an apiary can trigger several consecutive problems.

Colonies reduce their flight activity and collect less nectar and pollen. The queen may reduce egg laying because of food shortages. Weakened colonies become more vulnerable to robbing, disease and parasites. Preparation for winter is disrupted. During a mass attack, the losses include not only the foraging bees, but also the queen, brood, wax combs, stored honey and the colony’s entire future productivity.

The damage also has a broader agricultural effect. The loss of managed and wild pollinators means reduced pollination of fruit crops, vegetables and wild plants. The giant hornet is therefore not merely a problem for hive owners, but a potential threat to an entire ecological and agricultural system.

Control Begins with Correct Identification

The first and most important control measure is not poison, but information. In an area where the species has not been established, every credible record must be treated as the possible beginning of an invasion.

The suspicious insect should be photographed from a safe distance. It is useful to include an object in the photograph for approximate scale. The exact location, date, time, direction of flight and behaviour should be recorded. A suspected nest must not be destroyed, its entrance must not be blocked, and nobody should enter an underground cavity.

When there is genuine suspicion, the information should be forwarded to the competent plant health and food safety authorities, the local beekeeping association or a specialist entomologist. Experience from the United States shows that approximately half of the confirmed discoveries began with reports from members of the public, while all discovered nests were directly or indirectly connected with such reports.

Protecting the Apiary Itself

When the presence of a giant hornet has been confirmed, the beekeeper should work as part of a coordinated programme, not independently. Measures around the hives may reduce losses, but they do not replace locating and destroying the hornets’ nest.

Reducing and Protecting the Hive Entrance

The entrance can be narrowed or protected with a strong metal grid that allows bees to pass while preventing the large hornet from entering the hive. The construction must not create severe congestion, interfere with ventilation or injure the bees. Protective screens and anti-robbing tunnels can make direct entry more difficult for the predator.

This measure does not stop hunting in front of the hive, but it may prevent an external attack from developing into complete occupation of the honey bee nest.

Maintaining Strong Colonies

A strong colony has more guard bees, better temperature regulation and a larger reserve when losses occur. Weak colonies, nuclei and splits should be monitored particularly carefully. Unnecessary spills of honey, wax waste and exposed sweet foods around the apiary should be avoided because they attract wasps and hornets.

Temporary Relocation

When predation pressure is concentrated and the location of the attacks is known, temporarily moving the threatened colonies may save the apiary. However, this should be coordinated with the authorities when official monitoring is in progress, because moving hives and equipment may complicate the tracking of the attacking hornets.

Traps — Useful for Monitoring, but Not Harmless

Traps can reveal whether the species is present, during which periods it is active and in which direction the workers are flying. Various types of bait and traps for queens and workers were used during the American programme.

However, placing numerous random bottles filled with sweet liquid is not automatically an effective control method. Sugary and fermenting baits may kill enormous numbers of flies, butterflies, native wasps, honey bees and other beneficial insects. Official guidance for Vespa mandarinia requires traps to be as selective as possible and not to attract honey bees or other pollinators.

A trap is most useful as an early detection tool or for capturing a live specimen that specialists can mark and track. By itself, it rarely solves the problem of a large active colony.

The Most Effective Method — Finding the Nest

As long as the nest exists, it continuously produces new attackers. Killing several dozen workers around an apiary may temporarily reduce pressure, but it does not interrupt the life cycle.

During the American operation, live hornets were captured, fitted with miniature radio transmitters and released. Tracking their flight led teams to hidden nests in forests and tree cavities. Specially equipped personnel then neutralised the colony and removed the brood, queens and combs.

This is the essential difference between genuine control and the endless killing of individual insects. Control of an invasive hornet must target the reproductive centre — the nest — and must be completed before the new generation of queens emerges.

Insecticides, poisoned bait and nest treatment may be used only by competent teams, in accordance with the law and the specific circumstances. Incorrect use poses a risk to honey bees, wild pollinators, birds, water sources, domestic animals and humans. Official programmes provide for controlled treatment, physical removal of the entire nest and subsequent monitoring of the area.

What the Beekeeper Must Not Do

The beekeeper must not chase a flying hornet without a tracking plan. A suspected underground nest must not be excavated without professional help. Its entrance must not be blocked, because the insects may find another exit. Insecticides must not be sprayed randomly around the hives. Hundreds of non-selective traps that kill more beneficial insects than pests must not be installed.

Most importantly, every large hornet must not automatically be declared to be Vespa mandarinia. Panic leads to the indiscriminate destruction of native species that play their own role in nature as predators of caterpillars, flies and other insects.

The Real Lesson for Bulgaria

The giant Asian hornet should neither be transformed into a legendary monster nor underestimated. For the Bulgarian beekeeper, the native European hornet, the Oriental hornet and the possible future arrival of the yellow-legged Asian hornet, Vespa velutina, are currently of more immediate importance.

However, global trade transports containers, timber, soil, plants, machinery and goods between continents within days. One fertilised queen arriving in a suitable place may establish a new population. The case in North America demonstrated both how easily a foreign species may be introduced and how successfully it can be stopped when government authorities, scientists, beekeepers and citizens act in time.

The giant Asian hornet is a warning. The future of beekeeping will not depend only on the queen, forage, weather and the control of Varroa mites. It will also depend on our ability to recognise new biological threats before they become part of the landscape.

When the first nest is found in time, control requires effort. When the first hundred nests remain unnoticed, control may continue for decades.

Where to Report Invasive Hornets in Bulgaria

When the Asian yellow-legged hornet, Vespa velutina, the giant Asian hornet or another unusual non-native species is suspected, the first report should be made to the local Regional Inspectorate of Environment and Water, abbreviated in Bulgarian as RIEW or RIOSV.

The Ministry of Environment and Water and the regional environmental inspectorates are responsible for the early detection of invasive alien species. Vespa velutina and Vespa mandarinia are included among the invasive species monitored by the Ministry.

For Plovdiv and Plovdiv Province

RIEW — Plovdiv

• Green Line during working hours: 032 643 245

• Outside working hours: 0889 404 812 or 0882 393 749

• Email: riosv@plovdiv.riew.gov.bg

This is the most direct contact for an apiary in Plovdiv, Konush or another settlement in Plovdiv Province.

National Contact for the Ministry of Environment and Water

When it is unclear which regional inspectorate is responsible, or the local inspectorate does not respond:

• Green Line during working hours: 02 988 82 05

• Outside working hours: 0887 088 440

• Switchboard: 02 940 60 00

• Email for official registration: edno_gishe@moew.government.bg

The Ministry officially publishes the first two numbers as national Green Line telephone numbers.

Contacts for All Regional Inspectorates of Environment and Water

The first number is the Green Line during working hours, while the second is the number for reports outside working hours. The listed email addresses are the official addresses of the inspectorates.

What Exactly Should the Report Contain?

It is not enough to write only, “There is a large hornet.” Include:

• the exact location — settlement, local area and, if possible, GPS coordinates;

• date and time;

• clear photographs from above and from the side, or a short video;

• approximate size;

• number of hornets observed;

• whether they are hunting in front of the hives and the direction in which they fly away;

• a photograph of the nest taken only from a safe distance;

• the name and telephone number of the person submitting the report.

A suitable email subject line is:

“Urgent report of a suspected invasive Asian hornet — [settlement]”

A report should be submitted when an unusual species is observed or when Vespa velutina or Vespa mandarinia is suspected. The presence of a single European hornet or Oriental hornet around a hive is not proof of an invasive species.

When there is an immediate danger to people, multiple attacks, or a nest next to a home, playground or busy public place, 112 should also be called. No independent attempt should be made to remove, burn or spray the nest.

What Medicines and Equipment Should Be Kept at the Apiary for First Aid After Hornet Stings?

Apiary First-Aid Kit for Hornet Stings

The most important point is to understand that there are two different situations:

1. Local reaction — pain, redness and swelling limited to the area around the sting.

2. Anaphylaxis — a generalised, rapidly developing reaction that may stop breathing and circulation.

In cases of anaphylaxis, the life-saving medicine is adrenaline, not an antihistamine, corticosteroid or calcium.

Essential Equipment

1. Two Adrenaline Auto-Injectors

A beekeeper who has previously experienced a general allergic reaction after a sting should be examined by an allergist and should carry two prescribed adrenaline auto-injectors containing an appropriate dose.

Two are required because the first dose may not be sufficient. When there is no improvement after five minutes, the second auto-injector should be administered. The devices must be within their expiry date, and the beekeeper and people close to them should practise using a trainer auto-injector.

Important:

• Auto-injectors must not be left permanently inside a hot car or metal shed.

• They must be protected from prolonged high temperatures and freezing.

• They should be checked at least once a month.

• They must not be locked away where nobody can reach them.

• The name of the person for whom they were prescribed should be written on the box.

Prolonged storage above the recommended temperature or freezing may damage the medicine or the injection mechanism.

Adrenaline ampoules and syringes are not recommended for unsupervised use by an untrained beekeeper. It is easy to confuse the concentration, dose or method of administration. Auto-injectors are designed for use by non-medical persons.

2. Equipment for an Ordinary Local Reaction

It is sensible for the first-aid kit to contain:

• a cold compress or two instant cold packs;

• clean water, liquid soap or saline solution;

• sterile gauze;

• skin antiseptic;

• tweezers and a rigid plastic card for removing a visibly retained stinger;

• an oral antihistamine selected after advice from a doctor or pharmacist;

• 1% hydrocortisone cream for use on unbroken skin;

• paracetamol or ibuprofen for pain, provided the person has no contraindications.

In the case of a local reaction, the area should be washed and a cold compress wrapped in cloth should be applied for approximately 20 minutes. The affected limb should be kept raised whenever possible. An antihistamine may relieve itching, but it does not treat anaphylaxis.

It is also useful to keep a marker pen in the kit. The boundary of the swelling can be outlined and the time written next to it. This makes it possible to see whether the swelling is expanding rapidly.

3. Emergency Equipment

Useful items include:

• a charged mobile telephone;

• an external battery or power bank;

• a card showing the exact address and GPS coordinates of the apiary;

• a clearly written instruction: “In the event of anaphylaxis, call 112”;

• scissors;

• nitrile gloves;

• an emergency thermal blanket;

• a pocket resuscitation mask with a one-way valve;

• printed instructions for the specific auto-injector;

• a list of allergies, medicines and emergency contact telephone numbers for people who regularly work at the apiary.

At a large remote apiary, an automated external defibrillator is a valuable additional safety measure, but only when the people present know where it is and have been trained to use it.

How to Recognise Anaphylaxis

After a sting, even one of the following signs is sufficient to suspect anaphylaxis:

• swelling of the tongue or throat;

• a hoarse voice or difficulty speaking;

• difficult, noisy or wheezing breathing;

• tightness in the throat;

• persistent coughing;

• sudden dizziness, confusion or fainting;

• pale, cold and clammy skin;

• severe abdominal pain or vomiting after the sting.

Hives may be present, but they may also be absent. In allergy to insect stings, abdominal pain and vomiting may also be signs of anaphylaxis.

The Correct Sequence of Actions During Anaphylaxis

1. Administer the adrenaline auto-injector immediately into the middle of the outer thigh, following the instructions for the specific device. It can usually be administered through clothing.

2. Call 112 immediately and state clearly:
   “Anaphylaxis following a hornet sting. Adrenaline has been administered.”

3. Place the person flat on their back with their legs raised. They must not stand or walk, even if they say they are feeling better.

4. When breathing is severely difficult, they may be placed carefully in a more upright position, but with their legs extended and without any sudden standing movement.

5. If there is no improvement after five minutes, administer the second auto-injector, usually into the other thigh.

6. If the person is unconscious but breathing, place them in the recovery position.

7. If they are not breathing normally, begin chest compressions and rescue breathing, and use a defibrillator when one is available.

This is the officially recommended first-aid sequence: adrenaline, 112, correct positioning and a second dose after five minutes if symptoms persist.

What Must Not Be Regarded as a Life-Saving Medicine

The following do not replace adrenaline:

• antihistamine tablets or injections;

• Urbason, methylprednisolone or other corticosteroids;

• calcium;

• an asthma inhaler;

• a cold compress;

• vinegar, bicarbonate of soda, alcohol, ammonia or propolis.

An antihistamine may reduce itching and skin rash, but it does not open a swollen airway and does not restore falling blood pressure. Corticosteroids act too slowly to serve as first aid during rapidly developing anaphylaxis. They must not delay adrenaline administration or the call to 112.

A tourniquet must not be applied above the sting. The skin must not be cut and the venom must not be sucked out.

When Emergency Medical Help Is Required Even Without a Known Allergy

Urgent medical assessment is required in the following situations:

• a sting inside the mouth, on the tongue or in the throat;

• a sting close to the eye;

• multiple stings;

• rapidly expanding swelling;

• dizziness, vomiting or general weakness;

• a previous severe reaction;

• difficulty breathing or swallowing.

Multiple stings may cause a toxic reaction even in a person who is not allergic.

The Most Practical First-Aid Kit for a Beekeeper

The following should be kept in one clearly marked box:

Two personal adrenaline auto-injectors for every person known to be at risk, cold packs, an antihistamine, hydrocortisone cream, a painkiller, water and soap, saline solution, gauze, gloves, tweezers, a plastic card, scissors, a thermal blanket, a resuscitation mask, an anaphylaxis instruction sheet and the exact coordinates of the apiary.

Every beekeeper who has experienced swelling away from the sting site, a generalised rash, breathlessness, dizziness or faintness should be examined by an allergist. In addition to an auto-injector, venom immunotherapy may be discussed. This treats the underlying cause of the severe allergy rather than merely treating the next reaction.

What Is a Cold Pack?

A cold pack is a small sealed pouch used as a rapid cold compress following a sting, swelling, sprain or injury.

There are two types:

Instant Cold Pack

This is kept in the first-aid kit without refrigeration. When needed, the pouch is squeezed or bent firmly, causing an inner capsule to break. The pack becomes cold within a few seconds. It usually remains cold for approximately 15–30 minutes. This is the most suitable type for an apiary.

Reusable Gel Pack

This is stored in a freezer or cool box. After use, it can be chilled again. It is suitable only when reliable refrigeration is available at the apiary.

A cold pack must not be placed directly on the skin. It should be wrapped in a thin cloth or gauze and applied to the affected area for approximately 10–20 minutes. This reduces pain and local swelling.

When looking for such an item in a pharmacy or online, use the following terms:

“instant cold compress”, “instant cold pack” or “cold pack”.

It may help with a local reaction, but it does not treat anaphylaxis and does not replace an adrenaline auto-injector or a call to 112.

What Should a Beekeeper Do When a Hornet Scout Appears at or Above the Hive Entrance?

First, the word “scout” needs clarification. In the case of the giant Asian hornet, Vespa mandarinia, an individual hornet may indeed discover a honey bee colony, leave a chemical mark and subsequently attract other hornets. With Vespa velutina, a hornet observed in front of the hive is more often a hunting worker hovering in the air and intercepting returning bees.

In either case, it should not simply be watched until it flies away.

First Actions

1. The Beekeeper Must First Put on Full Protective Clothing

An attempt must not be made to catch a large hornet with bare hands or while wearing only a veil. A complete beekeeping suit, gloves, fully closed footwear and facial protection are required. Hornets can sting repeatedly, and when agitated they release alarm chemicals.

2. Photograph the Insect Before Destroying It

Several clear photographs or a short video should be taken:

• from above and from the side;

• showing the legs and abdomen;

• showing the head, if possible;

• beside the hive entrance for approximate scale.

Record the date, time, exact place and the direction in which the hornet flies away. This is particularly important when Vespa velutina is suspected, because Bulgaria is still in a position where early detection may allow the first nest to be destroyed before the species becomes established.

The Ministry of Environment and Water provides methods for reporting invasive species, including the European Commission reporting system and the Green Line of the relevant Regional Inspectorate of Environment and Water.

3. It Is Better to Capture the Hornet Than Merely to Chase It Away

An isolated hornet can be captured with an insect net and placed in a strong transparent container with a tightly closing lid. This should be attempted only when the beekeeper is properly protected and can do it without unnecessary risk.

A live captured specimen is extremely valuable. It can be identified by a specialist, and during an organised operation live hornets may be used to determine the direction of the nest. Tracking workers back to their nest is one of the most effective methods of control.

When capture is impossible, an individual attacker may be killed mechanically or with an electric insect swatter racket. However, it should not be crushed on the landing board. Crushing destroys identifying features and may leave chemical substances from the body and sting apparatus on the hive. In Vespa mandarinia, chemical marking of the honey bee nest is part of the preparation for a group attack.

Immediate Protection of the Hive Entrance

4. Narrow the Entrance, but Do Not Close It

The hive entrance should be reduced to a width that the colony can defend effectively. The hive must not be sealed completely, because this would interrupt ventilation and leave returning bees outside.

An even better measure is to install an anti-hornet entrance guard or strong grid that allows honey bees to pass but prevents the large hornet from entering the hive. The openings should be adapted to the local honey bee population and to the attacking species. Openings that are too narrow may trap drones, pollen-laden workers and dead bees.

An entrance reducer does not stop hunting outside the hive, but it prevents penetration and occupation of the honey bee nest.

5. Install a Protective “Muzzle”

This is a mesh frame or tunnel placed in front of the hive entrance. It moves the hornet’s hovering position away from the actual entrance and gives the bees several possible directions in which to enter and leave.

Mesh muzzles may reduce stress and improve flight activity when predation pressure is moderate. However, they are not impenetrable protection. During a severe attack by a large nearby Vespa velutina colony, the muzzle alone may be insufficient.

Actions to Take During the Same Day

6. Check All Hives

A single hornet may select the weakest colony, split or nucleus. The following should therefore be checked:

• weak colonies;

• hives with wide entrances;

• colonies with queen problems;

• landing boards with many dead or crawling bees;

• exposed feeders and spilled syrup.

All entrances should be adjusted according to the strength of the colonies. Exposed honey, syrup, wax waste, combs and dead bees must not be left around the apiary because they attract wasps and hornets.

7. Begin Monitoring Instead of Randomly Placing Bottle Traps

The beekeeper should record:

• how many hornets appear during a period of 10 or 30 minutes;

• which hives they visit;

• at what time of day they appear;

• the direction in which they fly after capturing a bee.

A camera aimed at the hive entrances may be helpful. If the hornets repeatedly fly away in the same direction, this is valuable evidence when searching for the nest.

Ordinary bottle traps filled with sweet fermenting liquid are not the best first measure. They may kill many non-target insects, while their protective effect on the colonies is often limited. When traps are necessary, selective traps should be used, checked frequently and positioned strategically rather than distributed throughout the entire area.

When the Situation Becomes Serious

A single native European or Oriental hornet does not necessarily mean that the colony is about to be destroyed. However, the following signs indicate organised or persistent pressure:

• the same type of hornet returns at short intervals;

• several hornets hover simultaneously in front of the hives;

• the bees gather inside and almost stop flying;

• decapitated or torn bees are found in front of the entrance;

• the attackers attempt to enter the hive;

• pressure continues for several consecutive days.

At that stage, the main objective is no longer to kill individual hornets, but to locate and destroy the nest. Official and scientific recommendations identify this as the most effective solution.

A nest high in a tree, inside a building or underground must not be attacked by the beekeeper using fire, water, a firearm or a random insecticide. Destruction requires specialised protective clothing, securing the area and appropriate equipment.

The Most Sensible Practical Sequence

When one suspicious hornet is observed, the beekeeper should:

protect themselves → photograph it → capture it if possible → reduce and protect the hive entrances → observe the direction and frequency of flights → immediately report any suspected invasive species.

The greatest mistake is to chase the hornet away and forget about it. If it is the first hunting worker from a nearby nest, it or other workers will probably return. If it is a genuine scout of a giant species, the time between the first detection and a group attack may be decisive.

What Is an Electric Insect Swatter Racket?

An electric insect swatter racket is a device resembling a small tennis racket, but its frame contains a metal mesh under electrical voltage. It is used against mosquitoes, flies, wasps and other flying insects.

When the insect touches two parts of the mesh at the same time, an electric current passes through it, stunning or killing it. The device operates with batteries or a rechargeable battery and is activated by a button on the handle.

There are several important limitations when it is used against a hornet:

• one strike may only stun the hornet rather than kill it;

• a fallen hornet may fly again or sting;

• it must not be picked up with a bare hand;

• it must not be swung among flying honey bees in front of the hive, because bees will also be killed;

• it must not be used against a nest or a group of hornets;

• it must not be used in rain, with wet hands or close to spilled alcohol, petrol or other flammable substances.

When it is used against one hornet, the beekeeper should wear protective clothing. After the hornet has been stunned, it should be covered with a jar or box without being touched. When an invasive species is suspected, it is better to preserve the specimen intact for identification than to tear it apart.

A more precise name is electric insect swatter racket or electric racket for flying insects.

What Is a Protective Mesh “Muzzle”?

The expression “protective mesh muzzle” is a literal translation of the French word muselière. In English, clearer descriptions would be:

• a mesh tunnel in front of the hive;

• a protective mesh cage;

• a mesh hive vestibule.

It is a structure made from a wooden, metal or plastic frame covered with mesh. It is attached to the front wall of the hive and extends approximately 25–35 centimetres in front of the entrance. It forms a kind of veranda or tunnel in front of the hive. One commercial model is 34 centimetres deep and uses a 6 × 6 millimetre mesh. ([icko-apiculture.com])

What It Looks Like

Several versions can be seen in the photographs:

1. The first photograph shows a simple wooden tunnel covered with curved metal mesh. This is a classic protective muzzle without a trap.

2. The second photograph shows a low transparent vestibule. The bees pass through designated openings, while the hornet is kept away from the actual entrance.

3. The third and fourth photographs show more complex models combining a protective muzzle with a hornet trap.

How It Protects the Bees

The Asian yellow-legged hornet often hovers directly in front of the hive entrance. The bees are forced to slow down and approach one narrow point, making them easy prey. Vespa velutina hunts intensively in front of hives.

The mesh muzzle changes this situation in several ways:

• it keeps the hornet away from the actual hive entrance;

• it creates a protected volume in front of the hive;

• it allows bees to leave through numerous openings instead of one point;

• it makes it more difficult for the hornet to predict where the next bee will emerge;

• it prevents the large predator from entering the hive directly;

• it reduces fear and the tendency of the bees to remain “locked” inside.

Its main purpose is not to make every bee unreachable, but to disrupt the hornet’s convenient hunting position. Research and practical programmes by ITSAP indicate that muzzles may help attacked colonies continue working and prepare better for winter. ([itsap.asso.fr])

How the Bees Pass Through

In models with small mesh openings, honey bees pass through holes approximately 5.5–6 millimetres wide, while the larger hornet cannot. Other constructions use larger mesh, but their geometry, depth and additional narrow entrance prevent easy access to the landing board. ([icko-apiculture.com])

The dimensions must not be copied blindly. Openings that are too small may obstruct:

• drones;

• bees carrying large pollen loads;

• the removal of dead bees;

• heavy flight activity during a strong nectar flow;

• ventilation during hot weather.

The structure should therefore be easy to remove and clean, and bee traffic should be observed carefully during the first few days.

It Is Not the Same as an Ordinary Entrance Grid

There is an important difference.

An entrance grid is placed almost directly over the hive entrance. Its main purpose is to prevent the hornet from entering the hive.

A mesh muzzle projects forward and creates a three-dimensional protected area. It does not merely block the entrance; it changes the way the bees take off and land.

A flat metal barrier with narrow holes is therefore not a true muzzle.

Ordinary Muzzle and Muzzle-Trap

Ordinary Protective Muzzle

This is a mesh tunnel without a trap for hornets. It is non-lethal. It does not kill the predator, but makes hunting and entry more difficult.

Its advantages are simplicity, low cost and a low risk to other insects.

Muzzle-Trap

This version has funnels, one-way openings or an upper chamber. The hornet enters the structure, moves upwards or towards the light and enters a compartment from which it has difficulty escaping.

Such a model is more complex and must be checked regularly because non-target insects may also enter. Modern commercial constructions combine a protected area in front of the landing board with a removable capture chamber.

What the Muzzle Cannot Do

The muzzle:

• does not destroy the hornets’ nest;

• does not completely stop hunting around the apiary;

• does not protect bees when they fly further away;

• does not replace locating and removing the nest;

• is not sufficient when dozens of hornets are attacking one hive.

The hornet may learn to wait outside the mesh and still capture bees. The construction is therefore a means of reducing pressure, not absolute protection.

Practical Design for a Bulgarian Beekeeper

For an ordinary hive, a wooden frame can be made with the same width as the front wall, a depth of approximately 25–35 centimetres and a height of approximately 15–20 centimetres. The sides, top and front are covered with strong galvanised or plastic mesh. The bottom may consist of the existing landing board or may also be covered with mesh.

The structure should:

• fit tightly against the hive without side gaps;

• not obstruct ventilation openings;

• not move in strong wind;

• be removable quickly for hive inspections;

• allow dead bees to be removed;

• have no sharp wire edges.

In Bulgaria, similar protection may also be tested against Oriental or European hornets, but their sizes and behaviour differ from those of Vespa velutina. French designs must therefore not automatically be regarded as fully suitable for every local species.

What Is a Selective Hornet Trap?

An ordinary plastic bottle containing beer, syrup or fermenting juice is a non-selective trap. Honey bees, bumblebees, butterflies, flies, beetles and native wasps may die inside it.

A selective trap is designed so that:

• the target hornet can enter;

• larger native species cannot pass through the entrance;

• honey bees and smaller insects have escape openings;

• the insects do not drown in the bait;

• the trap can be inspected and non-target species released.

It is important to understand that “selective” does not mean perfectly selective. During tests of different models in 2024, the best-performing trap contained only 25% Asian hornets among a total catch of 2,771 insects. Even a good trap therefore affects other species and must be checked every day.

Main Components

A good trap has five important components.

1. Calibrated Entrance

The opening is selected according to the target species and the season. For example, the VespaCatch Select system recommends different openings depending on the intended target.

The wider the entrance, the more non-target insects may enter.

2. Entrance Funnel

The entrance should not simply be a round hole. A cone or tunnel narrowing inwards is installed on the inside. The hornet enters because of the smell of the bait, but has difficulty finding the small return opening.

3. Emergency Escape Openings for Small Insects

Narrow slits approximately 5.5 millimetres wide are made in the upper or side section. Honey bees and many smaller insects can escape through them, while Vespa velutina remains inside. ITSAP describes 5.5-millimetre slits in a selective “nasse-type” trap. ([itsap.asso.fr])

4. Inaccessible Liquid Bait

Hornets should be able to smell the bait and consume a small amount, but they should not fall into the liquid. This is achieved using:

• a fine grid above the reservoir;

• cotton wicks;

• a sponge that absorbs the liquid;

• a separate lower chamber.

Honey bees and other insects are therefore not drowned. Modern designs use anti-drowning filters or cotton wicks.

5. Transparent Chamber

The trap should be transparent so that it is possible to see:

• what has been captured;

• whether live honey bees are present;

• whether a suspected invasive species has been caught;

• whether the trap is already overcrowded.

The transparent upper section also takes advantage of the hornets’ tendency to move towards light.

How to Make a Practical Selective Trap

The suggested design is intended mainly for monitoring and temporary live capture. It is not a certified commercial trap.

Required Materials

• a transparent plastic box with a lid, approximately 2–3 litres;

• two small plastic funnels;

• plastic washers with openings of 8, 9 and 10 millimetres;

• fine plastic or stainless-steel mesh;

• a small bait container;

• cotton wicks or a sponge;

• silicone sealant or hot glue;

• wire or strong cord;

• a drill and file;

• a vernier calliper for accurate measurement.

Step-by-Step Construction

1. Entrances

Make openings for the funnels in the upper half of two opposite walls. The narrow end of each funnel should point inwards.

Install a replaceable washer at the narrow end:

• 9 millimetres for spring monitoring of Vespa velutina;

• 8 millimetres for workers during summer;

• 10 millimetres for targeted capture of the Oriental hornet.

The internal tunnel may be approximately 30–50 millimetres long. It should project into the trap without touching the walls or bottom.

2. Escape Slits

Make between six and ten elongated slits in the upper section:

• width: 5.5 millimetres;

• length: approximately 15–25 millimetres;

• all edges should be smooth.

The exact width is more important than the length. Measure using a vernier calliper, because a slit 7–8 millimetres wide may allow the target hornet to escape.

3. Separating the Bait

Place a small container of bait in the lower section. Install a mesh above it that prevents insects from falling into the liquid.

Two cotton wicks may pass through the mesh. Their lower ends remain immersed in the bait, while their upper ends are accessible to the insects.

Do not place poison or insecticide in the bait. A captured hornet may be eaten by a bird or another animal, and poisoned bait may be carried outside the trap.

4. Removable Bottom

The lower chamber should open separately so that:

• the bait can be replaced;

• the trap can be cleaned;

• non-target insects can be released;

• a suspected invasive hornet can be preserved for identification.

5. Positioning the Trap

Place the trap:

• in the shade;

• to the left or right of the apiary;

• along the suspected flight path of the hornets;

• not immediately in front of the hive entrances;

• in a place inaccessible to children and animals.

BeeVital recommends a shaded location beside the apiary or on a branch along the hornets’ route, because strong heating reduces the trap’s effectiveness. (BeeVital GmbH)

What Bait Should Be Used?

The most sensible approach is to use a ready-made attractant intended for Vespa velutina and to follow the manufacturer’s instructions. Food bait itself is not completely selective. Sweet and protein foods are sought by many different insects.

For example, the instructions for VespaCatch Select specify a mixture of:

• 10 ml specialised attractant;

• 50 g sugar;

• 200 ml water.

This recipe is intended for the specific commercial attractant. It does not mean that sugar and water alone will be sufficiently selective.

How Often Should the Trap Be Checked?

The trap should be checked every day. Honey bees, butterflies, beetles and native non-target species should be released. The manufacturer of VelutinaTrap also recommends daily inspection when other species are captured.

When Vespa velutina is suspected:

1. Do not open the trap outdoors.

2. Take clear photographs.

3. Place the entire trap inside a strong bag or transparent box.

4. Submit a report to the relevant Regional Inspectorate of Environment and Water.

5. Do not damage the specimen, because it may be required for species identification.

Where Can a Trap Be Purchased?

In Bulgaria

GoldenBee, Yambol — BeeVital VelutinaTrap

The Bulgarian shop GoldenBee offers VelutinaTrap, designed for capturing Vespa velutina while allowing honey bees and other smaller insects to escape.

At the time of checking, the published details were:

• trap: EUR 49 / BGN 95.84;

• attractant: EUR 10 / BGN 19.56;

• telephone: 0884 800 886;

• email: info@goldenbee.bg;

• address: 7 Obhoden Pat Sever Street, Yambol.

It is advisable to confirm availability and the exact model in advance.

European Manufacturers and Shops

VespaCatch Select

This is a relatively compact model with:

• adjustable entrance size from 7 to 11 millimetres;

• an anti-drowning grid;

• a conical filter;

• escape openings for non-target insects.

The model is produced by Véto-pharma and is sold through European beekeeping distributors.

BeeVital VelutinaTrap

This is a larger trap with separate transparent collection chambers. During ITSAP tests in 2024, the BeeVital version without an entrance reducer demonstrated the highest selectivity among the compared traps, although it still captured many non-target insects.

GOOD4BEES V2

A compact Swiss model with:

• a separate reservoir;

• cotton wicks;

• a flexible one-way cone;

• two levels of openings allowing small insects to escape.

The manufacturer explicitly states that the model is still undergoing certification and should not automatically be regarded as proven to be completely selective. At the time of checking, the online shop did not list Bulgaria among its standard delivery destinations.

Which Option Is Most Suitable for Bulgaria?

Since Vespa velutina has not yet been officially recorded in Bulgaria, the widespread placement of bottles and traps in every apiary is not recommended. National documents describe it as a species that may be introduced through transport and cargo, but that has not yet become established in the country.

The practical choice is:

• one commercially manufactured selective live-capture trap for monitoring when there is genuine suspicion;

• or a well-made transparent trap with a 9-millimetre entrance, 5.5-millimetre emergency escape openings and inaccessible bait;

• daily inspection;

• immediate reporting of any suspicious capture.

An ordinary bottle containing drowning liquid should not be called a selective trap, regardless of how it is advertised.

What Is a Commercial Selective Live-Capture Hornet Trap?

The expression “factory-made live selective trap” is not an official technical term. A more precise description is:

a commercially manufactured selective live-capture trap for hornets.

The three words mean:

• Commercially manufactured — produced by a company rather than made at home from a bottle or box.

• Selective — the entrances and exits are sized so that the target hornet is retained, while honey bees and some smaller insects can escape.

• Live-capture — the hornet does not fall into liquid and is not immediately killed, but remains alive inside a transparent chamber.

What It Looks Like

It usually has:

1. A transparent plastic chamber.

2. One or two entrance funnels.

3. Calibrated entrance openings, for example 8, 9 or 10 millimetres depending on the target species.

4. Small emergency escape openings for honey bees and other smaller insects.

5. A bait compartment protected by mesh so that insects do not drown.

6. An opening lid or removable chamber for inspection and release.

The hornet enters through the funnel, attracted by the smell. It then flies towards the bright transparent section and has difficulty finding the narrow return opening. A honey bee, fly or another smaller insect may leave through the special side slits.

Why Is It Useful for the Hornet to Remain Alive?

A live specimen can:

• be photographed clearly and identified by a specialist;

• be handed over to the Regional Inspectorate of Environment and Water or an entomologist;

• be marked and tracked back to the nest during an official operation;

• remain intact instead of being torn apart or damaged by an electric insect swatter.

This Does Not Mean That the Trap Is Completely Harmless

No trap captures only one single species. The word “selective” means that it is less harmful to other insects, not that it is completely infallible.

The trap must therefore be checked at least once every day. Honey bees, butterflies and other non-target insects should be released. When an invasive hornet is suspected, the trap should not be opened at the apiary. The entire trap should be placed inside a strong transparent box or bag, and a report should be submitted.

In other words, it is a ready-made transparent cage with funnels, size-calibrated openings and a separate bait compartment. It captures the hornet alive while allowing smaller insects to escape.

What Is an Attractant?

An attractant is a substance or mixture whose smell draws an insect towards a trap. Hornet attractants usually contain volatile aromas produced by:

• fermentation;

• alcoholic beverages;

• fruit and sugars;

• protein-rich food during certain periods of the season.

Technically, there is a difference:

• attractant — the concentrate or active aromatic substance;

• bait — the ready-to-use liquid or food placed inside the trap.

At home, we usually prepare a bait rather than a pure specialised attractant.

Can It Be Made at Home?

Yes, but no homemade recipe attracts only hornets. Selectivity depends more on the trap’s construction — entrance size, escape openings for smaller insects and separation of the liquid behind a mesh — than on the recipe alone.

For monitoring Vespa velutina, the most sensible homemade bait is ordinary pale beer containing approximately 5% alcohol. A field study in Italy found that during spring ordinary beer was both more effective and more selective than the commercial attractant tested, although results varied according to the season and trap design.

Recipe No. 1: The Simplest Beer Bait

Required:

• 200–330 ml pale beer;

• alcohol content of approximately 4.5–5%;

• a selective trap with a separate liquid chamber.

Use:

1. Pour 150–250 ml beer into the lower compartment.

2. Cover it with mesh or use a cotton wick so that insects can smell and taste the bait without drowning.

3. Place the trap in the shade.

4. Check it every day.

5. Replace the beer every 7–15 days, or sooner if it dries out, becomes mouldy or fills with insects.

A European monitoring initiative for Vespa velutina also recommends 330 ml of pale beer containing approximately 4.7% alcohol as an inexpensive bait that is relatively unattractive to honey bees. This does not mean that a honey bee will never enter.

Recipe No. 2: Fermenting Bait

This mixture has a stronger smell but is less selective:

• 1 litre water;

• 300 g sugar;

• 10 g fresh baker’s yeast;

• 50 ml beer.

Dissolve the sugar in the water, add the beer and yeast, and leave the mixture in a loosely covered container for 12–24 hours. Place approximately 150–250 ml in the trap.

This recipe has been used during field research against Vespa velutina. However, the study found that widespread placement of such traps did not reliably reduce damage and affected non-target insects. The mixture is therefore more suitable for limited monitoring than for use in dozens of traps around an apiary.

Recipe No. 3: Using a Specialised Concentrate

This is no longer a completely homemade recipe. For VespaCatch, the manufacturer specifies:

• 10 ml concentrated attractant;

• 200 ml water;

• 50 g sugar.

The solution should be replaced when the trap becomes full or after approximately three weeks. The exact composition of the concentrate has not been published as a homemade formula and cannot be reproduced simply by mixing sugar and water. ([Veto-pharma][4])

What Must Not Be Added?

Do not add honey or syrup. They may strongly attract honey bees and increase the non-selective catch.

Do not add washing-up liquid when the trap is intended for live capture. Detergent reduces the surface tension and causes trapped insects to drown.

Do not add insecticide or poison. Poisoned bait may harm other insects, birds or animals and prevents the live hornet from being identified and tracked.

Do not place meat or fish in a general monitoring trap. They may attract native wasps, flies and other insects. Protein bait may be useful within a specific professional programme, but it is not a good universal selective bait.

Which Recipe Is Most Suitable for Bulgaria?

Since Vespa velutina has not yet been officially established in Bulgaria, the recommended option is:

200–330 ml of pale beer containing approximately 5% alcohol, placed behind a mesh or supplied through a wick inside one selective live-capture trap.

This is sufficient for monitoring when an unusual hornet has actually been observed. It is not sensible to place dozens of traps preventively in every apiary, because even the best designs capture other insects. Tests demonstrate that effectiveness and selectivity vary greatly according to the season, trap and bait.

When an unusual hornet has been captured, do not open the trap outdoors. Photograph it through the transparent wall and submit a report to the relevant Regional Inspectorate of Environment and Water.