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Legend has it that the Asian hornet appeared in Lot-et-Garonne hidden in a shipment of Chinese pottery or hidden in Asian wood shipped by boat in 2004.
This story is uncertain and divides. What is certain is that the Asian hornet won France and adapted perfectly there.
Investigation into a formidable predator that could well unbalance the ecosystem ...
Recognize the Asian hornet
- The Asian hornetor Vespa velutina measures between 2, 5 cm and 3 cm unlike the European hornet which is much larger (4 cm).
- The Asian hornet is active from late March to December depending on the weather. He fears the cold, and the rain prevents him from flying.
- Orange head, black forehead, brown hairy thorax. Its abdomen consists of brown abdominal segments bordered by a thin yellow stripe with a single orange-yellow segment. The tips of its legs are yellow.
- It has two sets of protruding wings that allow it to "hover" without getting tired. This ingenious technique of flight is formidable for hunting.
- Its nest looks like a hot air balloon. It can reach 60 to 90 cm in height and 40 to 70 cm in diameter. Located near a permanent water point, its population can reach between 10,000 and 18,000 individuals.
Reproduction of the Asian hornet
- Fertilized by males, queens store sperm in a pocket called a "spermatheca".
- Queens lay fertilized eggs which give birth to females.
- When they run out of sperm, they lay unfertilized eggs which will become males.
Asian hornet life cycle
- In spring, the queen or female founder comes out of hibernation.
- She makes a primary nest the size of a ping-pong ball with wood that she unrolls and models with her saliva. This nest is developed in stages, as she builds the beginning of a well each day to lay an egg.
- The eggs give birth to larvae which the queen must feed with protein.
- It takes three weeks for a larva to reach its maximum size. She then weaves a cocoon around her to transform into a nymph. Three weeks later, a hornet will be born emerging from its cocoon with its mandibles.
- The first births are workers.
- Gradually, the queen delegates and supervises to devote herself only to the laying.
- At the end of summer, the queen lays the first males and future queens.
- At the start of winter, the fertilized queens leave the nest and go into hiding (pile of wood, hiding in the ground ...) until the following spring.
The essential role of workers:
Unlike the queen who lives one year, the workers have a life expectancy of 20 to 30 days, as they are exposed to a multitude of dangers. Their role is essential.
- They must hunt to feed the brood (eggs, larvae and chrysalis).
- Find water.
- Maintain, enlarge and defend the nest.
Diet of the Asian hornet:
- 80% of bees for the proteins necessary for their energy needs. In addition, caterpillars, flies, butterflies and spiders.
- Ripe fruit for a carbohydrate intake, essential for brood rearing.
The Asian hornet, a formidable predator for bees
- Thanks to its two pairs of protruding wings, the Asian hornet can stalk and reach its prey while hovering. This technique allows him to easily capture the bees that forage. If you have lavender in your garden, you can easily observe a hunting party.
- Likewise, Asian hornets take up positions in front of hives. Stressed, the bees stop feeding and the colony weakens and develops diseases. Five hornets are enough to condemn a hive. They remove the workers, then reenter the hive to eat the remaining bees and larvae. The thorax of the bees is cut to be brought back into the nest and to feed the larvae.
- By attacking bees so much, the Asian hornet unbalances the entire ecosystem. Did you know that the bee is the only insect that pollinates orchids. This is just one example that shows it is essential to our survival.
ATto notethat the Asian hornet wreaks havoc in orchards because it also feeds on ripe fruit.
Predators of the Asian hornet:
Its main predator has remained in Asia and it is to be hoped that it will never spread to France.
- This is the dreaded Vespa Mandarina hornet. This giant can be 4 cm long with a wingspan of 8 cm and he feasts on honey. He is able to eat 300 bees in an hour. Its mandibles are sharp and its venom is capable of burning human flesh. It has been shown to be fatal in many cases.
- Tits, green woodpeckers and jays eat the larvae of Asian hornets.
Asian hornet and dangers to humans
The Asian hornet does not attack humans, it is rather elusive. It represents a danger if you approach its nest. It will then attack in fierce bursts until you are removed.
- Be careful if you get bitten several times or if you are allergic to its venom (hymenoptera venom).
- His sting is painful.
- Its stinger does not drop, so it can sting as long as its venom pouch fills.
- Possibility of anaphylactic shock
The fire department should be called in case of difficulty in breathing or if you feel unwell.
- To relieve yourself, wash and disinfect, then place an ice cube at the site of the bite.
- Remove rings and bracelets if the bite was on a hand or arm.
- Take paracetamol if it is not contraindicated for you.
Removing an Asian Hornet Nest
It is very dangerous not to try to destroy an Asian hornet nest. This is one of the only reasons they get aggressive. Contact a company or the fire department, but you may be charged for their intervention if the nest does not present a direct danger.
- The capture by trapping of the queens (from February to May) is the best solution, but the failures are numerous.
- Destruction of the nest limits the spread of the species.
To meditate : "Whoever rubs himself pricks himself" Louis XI
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